Electronics Basics Transformers

Electronics Basics

[ index ][ back ][ site search ] [ acronyms ] [ discussion ] [ mail to a friend ] [ post message ]

Component information

Index General Resistors Tubes Integrated circuits Capacitors Coils Transformers Magnetic materials Special electromagnetic components Sensors Relays RF components Solenoids Switches Diodes Thyristor and TRIAC Transistors FETs IGBTs Optoelectronics Crystals and crystal oscillators Fuses and similar protection devices Batteries Lamps Misc

General

fileC|0004Electronics20Basics20-20transformershtm (1 of 38) [200803 152200]

Electronics Basics

Few designers spend time pondering the traits of resistors capacitors or other simple passive components Determine the necessary nominal value tolerance and temperature coefficient for each instance in your circuit and youre pretty much done Consider the nonelectrical variables like package and pricing and youre a certifiable good corporate citizen

When it comes to the active components there are also many other things to consider

Component Handling Precautions - one should take reasonable care in handling all components especially nowadays when so many are of small size but certain components can be damaged by high voltage static charges

Electronic component v-i curve photos - transistors FETs photocell transformer capacitor How to read a semiconductor data sheet - Never design with typical specifications unless you are in the

habit of designing with meaningless data The front page of a data sheet for semiconductors and most other products contains the wishes and hopes of marketing Sadly wishes and hopes are not design parameters So the front page of a data sheet contains no useful information unless the marketers run out of lies

Resistor colour codes and capacitor values

Component markings explained A rudimentary resistor identifier - Select colors matching those of the resistor and get the value of the

resistor needs a browser which supports JavaScript Capacitor color codes - in Finnish Resistor color codes - text only version also available in Finnish Resistor Color Codes Semiconductor Classification - Semiconductor devices are classified by the manufacturer using a unique

part numbering system Semiconductor markings explained - what European and Japanise semicondictor component codes mean

also available in Finnish Surface Mount (SMD) TransistorsDiode FAQ The SMD Codebook - To identify a particular SMD device first identify the package style and note the ID

code printed on the device Now look up the code in the alphanumeric listing Transistor Info - transistor markings described Transistor marking codes

ResistorsResistors are electronic components used extensively on the circuit boards of electronic equipment Resistors are usually used to limit current attenuate signals dissipate power (heating) or to terminate signal lines Resistors are usually color coded with stripes to reveal their resistance value (in ohms) as well as their manufacturing tolerance

Most importans characteristics of resistor are the resistance tolerance of resistance and the power handling capacity Resistors are generally available from the fractions of ohms up to several megaohms (higher value special components are also available) Most small general purpose resistors have power handling capacity of around 025W Most resistors used to be this type and most electronics designs expect this kind of resistor unless the power rating is mentiones In typical circuits you can nowadays see resistors with power handling of 0125W up 1W Also special power resistors are available generally with power rating from few watt up to 50-100W Higherst power power resistors are generally built to metal case which is designed to be connected to a heatsink

Electronics Basics

The resistors are manufactured with some tolerance For example a typical resistor can have a 5 tolerance which means that the resistance value can be 5 higher or 5 lower than what the color code indicated There are special accurate resistors also available for example resistors with 1 or better accuracy

There are many differetn resistor types which are characterized by the material they are made of and how they are constructed Here are some details of different resistor types

Carbon film resistor cheap general purpose resistor works quite well also on high frequencies resistance is somewhat dependent on the voltage over resistor (does not generally have effect in pratice)

Composite resistor Usually some medium power resistors are built in this way Has low inductance large capacitance poor temperature stability noisy and not very good long time stability Composite resistor can handle well short overload surges

Metal film resistor good temperature stability good long time stability cannot handle overloads well Metal oxide resistor mostly similar features as metal film resistor but better surge handling capcity higer

temperature rating them metal film resistor low voltage dependity low noise better for RF than wire wound resistor but usually worse temperature stability

Thick film resistor Similar properties as metal fim resistor but can handle surges better cna withstand high temperatures

Thin film resistor good long time stability good temperature statiblity good voltage dependity rating low noise not good for RF low surge handling capacity

Wire wound resistor used mainly for high power resistors can be made ccurate for measuring circuits high inductance because consists of wound wire

In some applications resistors are used like a fuse (for example in some power supplies and telecom applications) In those applications the resistor burns up when it is overloaded In this type of application non-flammable resistor are used to avoid the flames and risk of fire If the application calls for non-flammable resistor (usually has white case) do not replace it with any other type Sometimes special resistors designed to be used as fuses are called fusible resistors

4 Band Resistor Color Codes Calculate Resistor Values from Color Codes Construction of low resistance shunts - how to make very low resistance resistors for measuring purposes

from normal wire Glossary of Potentiometer Industry Terms How to read resistor color codes Resistor Color Codes Resistor Color Codes Calculator Resistor Color Codes Table Resistor packs eliminate temperature drift - you can use a resistor pack to implement a 5-to-1 voltage

divider and an op-amp gain-setting network of shy4 (b) which exhibit low temperature drifts Resistor Selector - program finds resistor values for simple resistor circuits from given initial conditions

can find suitable resistors in E6 E12 E24 E48 and E96 standard values RMA Resistor and Flexible Resistor Color Codes Standard EIA Decade Resistor Values Table - The Electronic Industries Association (EIA) and other

authorities specify standard values for resistors sometimes referred to as the preferred value system The EIA E series specify the preferred values for various tolerances The number following the E specifies the number of logarithmic steps per decade

The Secret Life of Pots - As electronics tinkerers we all use potentiometers or pots for short We count on them to control all our musical gear and quite often get frustrated by their limitations As in all relationships a little understanding goes a long way Lets take a look at how pots work so we can use them better

Universal compensator neutralizes temperature coefficient - universal thermal-compensation module in Fig 1 can neutralize the temperature coefficient of both signs within a 06degC range universal thermal-compensation module can neutralize the temperature coefficient of both signs within about 06degC range

Electronics Basics

Tubes Audio Valves - link collection on electron tubes made for audio applications and related components

includes links to manufacturers delalersampdistributors datashees and more Basics of vacuum tubes in english How Tubes Work Mikes Electric Stuff - information on old tubes and related components Roumlhrentabellen Electron Tubes and Valves - electron tube data collection

Integrated circuitsIntegrated circuits are miniaturized electronic devices in which a number of active and passive circuit elements are located on or within a continuous body of material to perform the function of a complete circuit Integrated circuits have a distinctive physical circuit layout which is first produced in the form of a large scale drawing and later reduced and reproduced in a solid medium by high precision electro chemical processes The term integrated circuit is often used interchangeably with such terms as microchip silicon chip semiconductor chip and micro-electronic device

General

Components from Bebek catalogue - tietoa komponenteista jotka esiintyvaumlt Bebek Electronic Oyn asiakaslehdessauml

What Causes Semiconductor Devices to Fail

Power supply ICs

Voltage regulators (stabilizers) 78xx a 79xx by ST - warning about some possible problem if the regulator load is too low

Popular general purpose ICs

Standard logic ICs

4000B Series CMOS Functional Diagrams 4000 series CMOS logic IC pinouts 7400 series TTL logic IC pinouts 74xx54xx Family TTL Circuits - nice drawings of the most commonly used chips from 74xx series Specifications for various 74xx Chips Understanding Buffered and Unbuffered CD4xxxB Series Device Characteristics - Many CMOS

suppliers have concentrated on promoting buffered B-series products with applications literature focusing on the attributes and use of the buffered types This practice has left an imbalance in the understanding and application of both buffered and unbuffered gates In some instances customers are not using unbuffered products when they are the best choice for the intended application This application report offers clarification of the relative merits of the buffered and unbuffered CMOS devices

Electronics Basics

Operational amplifiers

The operational amplifier is the work horse of the analog world It is found in applications ranging from cellular phones to laptop computers to smoke detectors

Operational amplifiers are the child of the analogue signal processing age Ironically perhaps todays emphasis on digital systems shifts such computational duties from continuous-time to clocked-circuit operation but systems engineers require more op amps than ever before to bridge the analogue-to-digital divide

Two main factors now challenge semiconductor-device and end-user equipment designers alike the trend toward single-supply operation and the explosive growth in mobile devices Each of these factors adds its own requirements but both share the ever-lower power-consumption requirements that contemporary designs demand Single-supply operation now dominates op-amp applications for several reasons First its convenient you no longer have to design and accommodate multiple power supplies Just lowering the supply voltage from the traditional plusmn15V to say 5V helps you to conserve energy and minimise power dissipation

Certain applications such as audio demand low-noise performance The amplifier itself generates internal or amplifier noise The designer must account for the effects of amplifier noise because the wrong instrumentation amplifier can make amplifier noise dominant The most important parameter in low-noise design is the source impedance Low source impedance dictates selection of a low-voltage-noise amplifier High source impedance dictates that you select a low-current-noise amplifier And medium source impedance means that the amplifier selection is a compromise between voltage- and current-noise performance JFET is usually a better choice than CMOS for low-noise performance in the 20-Hz to 20-kHz frequency range

AC-Coupled Amplifier Requires No DC Bias - Recent improvements in op amp technology allow AC-coupled inputs without the need for bias resistors

Are Op Amps Really Linear - everybody knows that op amps are the most linear building blocks in the analog repertoire but every real amplifier has a bit of nonlinearity

A single-formula approach for designing positive summing amplifiers - This circuit-theory approach on op-amp design and analysis has two benefits You can use it on all op-amp designs without learning special formulas or cases article in pdf format

A Tutorial on Applying Op Amps to RF Applications Audio and Op amps circuits - Schematics of simple circuits Basic Active Filter Circuit Blocks - filters based on operational amplifiers capacitors and resistors Demystifying single-supply op-amp design - Battery-powered op-amp applications such as those

found in automotive and marine equipment have only a single available power source It may seem like a simple task to modify your op-amp design to work from a single voltage power supply but the change in performance will surprise you Single-supply applications have inherent problems that dual-supply op-amp circuits often overcome

Designing With Opamps - Audio design has for many years relied on a very small number of opamp types The TL072 and the 5532 numbers that will be immediately familiar to anyone involved in audio electronics have dominated the small-signal scene for many years There are however other opamps some of which can be very useful and a selected range is covered here

Design Trade-Offs for Single-Supply Op Amps - The trend toward low-voltage single-supply systems is fueled by designers attempts to balance the often contradictory goals of lower product size and cost vs longer battery life and better system performance This trend may be good for consumers but it complicates the task of choosing an appropriate op amp for a given application

Designing with op amps Single-formula technique keeps it simple - simple single-op-amp design technique uses one formula for both positive and negative gains

Dont let noise ruin instrumentation-amplifier performance - You cant afford noise in your circuit designs and certain applications such as audio demand low-noise performance You can minimize

Electronics Basics

external noise by considering noise during the board-layout stage For example you must make power and ground impedances small enough to minimize the effect of current spikes Using shielded interconnections and Faraday shields minimizing noise sources and liberally dosing the pc board with good decoupling capacitors are additional methods for eliminating external noise The amplifier itself generates internal or amplifier noise The designer must account for the effects of amplifier noise because the wrong instrumentation amplifier can make amplifier noise dominant

Dual op amp doubles output current - standard linear output current for high-speed op amps is approximately 30 to 40 mA this circuit doubles it using two operational amplifiers connected together

Dual-polarity amplifier has digital control - can amplify a signal either in an inverting or a noninverting mode

Feedback network silences op-amp resistor noise - information how to avoid noise on opamp feedback resistor network

High Performance Audio Op-Amp Quick Reference - most important technical data of some high performance operational amplifiers for audio use pdf file

Improved amplifier drives differential-input ADCs - ADCs with differential inputs are becoming increasingly popular This popularity isnt surprising because differential inputs in the ADC offer several advantages good common-mode noise rejection a doubling of the available dynamic range without doubling the supply voltage and cancellation of even-order harmonics that accrue with a single-ended input This document shows shows two easy ways to create a differential-input differential-output instrumentation amplifier

Internal Structure of Op-amps and Audio Power Amps Next generation op amps - achieving low power and high performance has been a daunting task Noise-figure curves ease the selection of low-noise op amps - evaluating plots of noise figure vs

source resistance makes it easy to select a low-noise amplifier for a given source resistance Noise and Operational Amplifier Circuits - application note in pdf format Op amp Myths - operational amplifier has become the quintessential icon of analog electronics and

there are many myths on them within electronics designers contrary to the prevailing dc-oriented view of these components the ac gain dominates the behavior of a classical op-amp

Op amps take the next step - Operational amplifiers are the universal building blocks for signal-conditioning duties And thanks to the proliferation of ADCs theyre now more popular than ever But contemporary design stresses low-voltage low-power operation that complicates traditional op-amp circuits First know your op amp

Operational Amplifiers - introduction to operational amplifiers Piecewise linear amplifier eschews diodes - common implementation of a piecewise linear amplifier

uses diodes in the feedback loop of an op amp but this circuit uses different method for that Portable analog design needs rail-to-rail op amps - Rail-to-rail op amps are mandatory in portable

designs because only they satisfy the design criteria of low noise high dynamic range signal sensing at the input rails and rail-to-rail output-voltage swing

Positive Feedback Terminates Cables - positive feedback along with a series output resistor can provide a controlled output impedance from an op-amp circuit with lower losses than would result from using an actual resistor

Simple techniques help high-frequency op amps drive reactive loads - modern high-frequency amplifiers are a cranky group that lose performance when driving capacitive and reactive loads but fortunately there is simple tricks to pacify poorly loaded amplifiers

Single stage gives logarithmic gain steps - by placing a variable component in the positive feedback loop of an op amp you can vary the gain of the stage logarithmically with respect to a linear resistance or conductance

Some Tips on Stabilizing Op-Amps - 4 page booklet in pdf format Spicing Up The Op-Amp - opamp design information Systematic approach makes op-amp circuits resist radiated noise The 5532 Opamp - The 5534 is a low-noise low distortion bipolar opamp This article gives in

introduction to it Two op amps make fast full-wave rectifier Understanding operational amplifier specifications - application note from Texas Instruments

Electronics Basics

Unique compensation technique tames high-bandwidth voltage-feedback op amps - unique and previously overlooked method allows a decompensated voltage-feedback op amp to achieve low-gain operation with high dc accuracy high slew rate and low harmonic distortion

Voltage follower with 1G ohm input resistance - This circuit uses an LM11 to form a voltage follower with 1G ohm input resistance built using standard resistor values

Wisely using rail-to-rail op amps - Low-voltage and portable applications require rail-to-rail-IO op amps to obtain dynamic range and maximum output-signal swing These op amps accept input voltages within 200 mV of both supply rails and their output voltage swings within 50 mV of the supply rails Rail-to-rail-IO op amps introduce unique errors and understanding these errors helps to minimize them and optimize performance

Other amplifier ICs

A Contumacious View of Current Feedback - IC amplifier performance is constantly under pressure new ideas for topologies come along from time to time

Class D Audio Power Amplifier ICs - Class-D topology makes use of a pulse-width modulation (PWM) scheme

Class D amplifiers provide high efficiency for audio systems - advances in MOSFET technology and integrated half- and full-bridge predrivers now make class D amplifiers a practical alternative to linear amplifiers in many applications

Composite amp provides high gain and bandwidth Differential-to-single-ended converter circuit - ouples the output drive and slew rate of a current-

feedback amplifier with the low-noise and low-offset characteristics of a voltage-feedback operational amplifier

Gain-Amps are worlds smallest and simplest op amps Internal Structure of Op-amps and Audio Power Amps Pushing the Limits of Audio Power Amplifiers

Comparators

Comparators compare two voltage levels and provideo digital 10 output depending on the input voltage levels Comparators have an op-amp front end and a digital back end that operates like a gate The comparator output stage may be an open collector transistor so it often connects to the logic supply through a pullup resistor Regardless of the input voltage the output voltage is saturated at either power-supply rail because the analog front end amplifies input voltages with an almost infinite gain

Adding hysteresis to comparators - Comparators have very high open-loop gain and without some type of positive feedback they have no noise immunity This column adds hysteresis to comparators to eliminate multiple switching on the output

Designing with comparators

Other analogue ICs

Analog ICs for 3V Systems - Single 3V operation is available for many op amps comparators and microprocessor supervisors and for some RS-232 interface ICs

How did analog ICs get that good - building blocks available on a typical IC fabrication process are really not very good in absolute terms because the key transistor parameters such as transconductance input threshold voltage and output impedance vary by at least plus or minus 20 and are not as good as can be produced in discrete form but with correct desing it is possible to make very high performance analogue ICs

Reinventing The Role Of AnalogMixed-Signal - not long ago analog and mixed-signal functionality

Electronics Basics

were treated as though they were an afterthought in the system design process but now markets move towards mixed-signal technology which combines analog and digital functionality

Selecting the Right CMOS Analog Switch - First developed about 25 years ago integrated analog switches often form the interface between analog signals and a digital controller This tutorial presents the theoretical basis for analog switches and describes some common applications for standard types

Analogue to digital converters

Blindingly fast ADCs - To get meaningful information not just data you need to know how your converter is looking at your signal

Delta-sigma analog-to-analog converter solves tough design problems Digital-servo and linear-regression methods test high-resolution ADCs EDN Hands-On Project Demystifying ADCs - esting demonstrates that high-speed AD converters

dont always perform up to spec Its Video Its PC Graphics No Its Digital TV - Know Your Video Format to Select the Right ADC

- PC and TV applications are converging requiring one box (set-top box TV set) to process signals that were originally used in different environments

Pay Attention To The Clock And Output Bus To Improve High-Speed ADC Designs To build data-acquisition systems that run from 5 or 33V know your ICs Twin DACs produce true bipolar operation

Digital to analogue converters

Take the rough edges out of video-filter design - Incorrectly processed image-frequency information can distort displays generated from digital-video sources Oversampling and well-implemented video-DAC-output filters can save the day but improperly designed filters can make matters worse Before you design your next digital-video system take some time to investigate video-reconstruction-filter design and trade-offs in oversampling

Voltage references

A quick guide to voltage references - A review of reference topologies and a quick look at the various ways that manufacturers specify references will help you pick the best part for your next design

Selecting Voltage References - Voltage references are simple devices but making the right choice for a given application can be a chore if you dont take an orderly approach This article simplifies the task with a review of the available reference types and a discussion of the specifications manufacturers use to describe them

Analogue signal swithcing and multiplexing ICs

How to Select the Right CMOS Analog Switch

CapacitorsA capacitor is simply two charged plates placed close together with a dielectric (non-conducting) material sandwiched between the plates When a charge is applied to one plate it repels charges on the opposite plate

Electronics Basics

until an equilibrium is established For direct current the capacitor charges up with a time constant that depends on the capacitance value and the impedance through which the current flows into the capacitor Once the capacitor is fully charged no more current flows This means that the capacitor is an effective block for direct current For alternating current (like audio signals) the response is more complicated The charge that develops on the capacitor depends on how fast the current is changing It takes time for the charge to build up and that time results in a frequency dependent delay (or phase shift) in the output signal

Capacitor device is often used to store charge in an electrical circuit A capacitor functions much like a battery but charges and discharges much more efficiently A basic capacitor is made up of two conductors separated by an insulator or dielectric The dielectric can be made of paper plastic mica ceramic glass a vacuum or nearly any other nonconductive material

Capacitor electron storing ability (called capacitance) is measured in Farads One Farad is actually a huge amount of charge (6280000000000000000 electrons to be exact) so we usually rate capacitors in microfarads (uF = 0000001F) and picofarads (pF = 0000000000001F ) Capacitors are also graded by their breakdown (ie smoke) voltage

There are very many different capacitors You have to realize that not all capacitors are equal A 1uF ceramic definitely is NOT the same thing as a 1uF tantalum You choose the device according to the application

Two parasitic effects of capactitors are effective series resistance (ESR) and series inductance High ESR will cause power loss in higher-frequency applications (caps will get hot) especially in switching power supplies High ESR also limits the effective filtering (your power supplies end up with more ripple) Except for very high frequency (multi-megahertz)applications a high inductance isnt quite so critical

The rated DC voltage is also very important Usually it is a good idea to select capacitors rated at least 15 times or twice the maximum voltage you think theyll ever see Temperature ratings also exist

The most common types are ones built using standard capacitor plates + insulator and then there are electrolytic capacitors Typical capacitors consists of some form of metal plates and suitable insulation material in between those plates This insulation can be some form of plastic paper mica ceramic material glass or air (some physical separation between layers) Those metal plates used in capacitors are usually thin metal foils This type of capacitors have usually very good propertied otherwise but the available capacitance is usually quite small (usually goes from pF to few microfarads) This kind of capacitors can take easily DC at both polaritied and AC without problems This typie of capacitors are availablewith various voltage ratings from few tens of volts up to few kilovolts as ready made components For special application same technique can be used for very high voltage capacitors

Here is overview of most common capacitor types

Ceramic Fairly cheap but not available in really high capacitances - 2uF-10uF are about the max for any practical devices Extremely low ESR Surface mount devices have essentially no series inductance and are commonly used to bypass high-frequency noise away from digital ICs Not polarized

Electrolytic Cheapest capactitance per dollar but high ESR Mostly used for bulk power supply Typical values 1uF-5000+uF Polarized Fairly durable but will literally explode if reverse-biased Tolerances of +-10 and +-20 are not uncommon

Tantalum The cadallac of capacitors Very low ESR (not as low as ceramic though) very high capacitance values available but expensive (10x electrolytic) Usually used where one might use electrolytics Polarized

Polyester Kinda expensive not very high capacitance values ESR not too bad Polyester capacitors have very very stable temperature characteristics (capacitance change is very small as temperature changes) Used where stable capacitance is important like oscillators and timers NOT polarized

Theres others of course such as X caps made to connect directly across mains AC power supplies that literally heal themselves after an overvoltage There are also so called Y capacitors which are used in mains filters

Electronics Basics

where they are connected between ground and live+neutral connectors Y-capacitors have special safety regulations related to them

Electrolytic capacitors are constructed using a metal electrodes put into some form of electrolytic liquid This kind of capacitor can give high capacitances (from microfarads to tens of thousands of microfarads) The typical voltage rating of electrolytic capacitor varies from few volts to few hundred volts The biggest disadvantage if electrolytic capacitors is that they are polarity sensitive you are only allowed to charge them only on one way The capacitors have the positive negative terminals marked The capacitor must be put in the right way to the circuit (putting it wrong way will cause serious damage to the capacitor)

For power supply smoothing capacitor applications where large capacitances are needed aluminium electrolytic capacitors are the most common choise

For power signal wire and power plane decoupling in digital electronics ceramic and tantalum capacitors are considered as the best solutions For RF applications ceramic capacitors are common Ceramics do not suit for all applications because most of ceramics have strange effects like changing capacitance with bias voltage

In audio applications type of insulation material does make a difference For audio applications IIRC ceramic paper mica electrolytic and tantalum are all considered inferior by high-end hifi people The plastic-film kind (especially polystyrene) are the preferred dielectric in very high quality audio applications

Nowadays a lot of talked about capacitor feature is ESR ESR is an abbreviation for Equivalent Series Resistance the characteristic representing the sum of resistive (ohmic) losses within a capacitor The ESR rating of a capacitor is a rating of quality A theoretically perfect capacitor would be loss less and have an ESR of zero (=no in-phase AC resistance) ESR is the sum of in-phase AC resistance It includes resistance of the dielectric plate material electrolytic solution and terminal leads at a particular frequency ESR acts like a resistor in series with a capacitor (thus the name Equivalent Series Resistance) This resister can cause circuits to fail that look just fine on paper and is often the failure mode of capacitors While ESR is undesirable all capacitors exhibit it to some degree

Materials and construction techniques used to produce the capacitor all contribute to the components ESR value ESR is a frequency dependent characteristic so comparison between component types should be referenced to same frequency Industry standard reference for ESR is 100kHz at +25degC Power dissipation within the capacitor and the effectiveness of the capacitors noise suppression characteristics will be related directly to the ESR value

Another important thing to keep in mind is ESL ESL (Equivalent Series Inductance) is pretty much caused by the inductance of the electrodes and leads The ESL of a capacitor sets the limiting factor of how well (or fast) a capacitor can de-couple noise off a power buss The ESL of a capacitor also sets the resonate-point of a capacitor Because the inductance appears in series with the capacitor they form a tank circuit which is tuned to some frequency

General

Ancient material yields latest passives - Ceramics meets modern materials science (and art too) to produce high-value stable nearly invisible capacitors

Capacitor - This is a short introduction to capacitors Capacitor ESR Ratings - The ESR rating of a capacitor is a rating of quality A theoretically perfect

capacitor would be loss less and have an ESR of zero It would have no in-phase AC resistance We live in the real world and all capacitors have some amount of ESR To understand why let us review what a capacitor is and what they are made of and how we rate them

Capacitors Technical Parameters - Can you help me make sense of some of the capacitor specifications I see in data sheets For example ESR ripple current DF and so on

Capacitor Terminology

Electronics Basics

CapSite 2002 Introduction To Capacitors - capacitor FAQ site information on nonideal characteristics of capacitors including ESR aging drift dissapation etc

CV Values Soar ESR Plummets - The development curve is flattening off in conventional tantalum electrolytic capacitors so alternative technologies are in demand The magic words enchanting designers now are niobium polymer and multianode technologies - innovations that promise the highest volumetric capacitance and lowest equivalent series resistance

Glossary of Capacitor Terms FaradNet - A Worldwide Capacitor Resource Covering all Aspects of Capacitor Technology How to read Capacitor Codes - Large capacitor have the value printed plainly on them such as

10uF (Ten Micro Farads) but smaller disk types along with plastic film types often have just 2 or three numbers on them

Supercaps for supercaches - Supercapacitors ultracapacitors electrochemical capacitors double-layer capacitors all alternative names for devices finding an ever-widening range of applications

The ABCs of integrated Ls and Cs - RF circuits need low-loss and high-Q passives for integration Understand capacitor soakage to optimize analog systems - Dielectric absorption can cause subtle

errors in analog applications

Electrolytic capacitors

Name electrolytic capacitor refers to capacitors where the dielectric is formed by an electrolytic process Wet electrolytic capacitors have an actual moist electrolyte while dry or solid electrolytic capacitors dont Most electrolytic capacitors have dielectric that is made up of a thin layer of oxide formed on a aluminum or tantalum foil conductor

Aluminium electrolytic is the term used by capacitor manufacturers for electrolytic capacitors constructed with aluminium electrodes This is the most commonly used type and most often then people talke about electrolytics they mean aluminium electrolytic capacitors

Tantalum electrolytic is the term used by capacitor manufacturers for electrolytic capacitors constructed with tantalum electrodes

The largest advantage of electrolytic capacitor is that they can fit large ampunts of electricity (large capacitance) to a very small size component

Electrolytic capacitors have several undesirable properties They are inherently polar devices meaning that the anode of the capacitor must be more positive than the cathode (There are also special true bipolar electrolytic capacitors available) Most electrolytic capacitors can withstand small and brief amounts of reverse voltages but this is not recommended The main concern is internal heat and gas generation You need to pay attention to correctly hooking a polarized capacitor like electrolytics If you push a polarized capacitor hard enough it is possible to begin electrolyzing the moist electrolyte Modern electrolytic capacitors usually have a pressure relief vent to prevent catastrophic failure of the aluminum can Be warned that large value capacitors may explode if abused very badly

Leakage currents are higher ESRs are higher and operating voltages and failure rates are higher than non-electrolytic capacitors Electrolytic capacitors have low self-resonance frequencies and are unsuitable for high frequency work Electrolytic capacitor tolerances are normally high The one factor that outweighs all these undesirable properties is the very high volumetric density that electrolytic capacitors exhibit This means that you get lots of capacity in small size package

Several metals such as tantalum aluminum niobium zirconium and zinc can be coated with an oxide film by electrochemical means These metal oxides are remarkable dielectrics under the proper conditions However the metal-metal oxide interface is rectifying That is in one direction it is a good insulator and in the other direction it is a conductor This is why capacitors are polar Non-polar electrolytic capacitors

Electronics Basics

are made by using two oxidized films back-to-back

Please note that with electrolytic capacitors the operation voltage can have effect on the capacitance Some electrolytic capacitors can show reduced capacitance values when operated very much below their designed operating DC voltage

Electrolytic Capacitors - What is an electrolytic capacitor Electrolytic Capacitors - Electrolytic capacitors are major components of any power converter in use

today Proper understanding of their characteristics allows designers to better utilize them while optimizing their designs This design note will shed some light on the main features of electrolytic capacitors

Guidelines For Using Aluminum Electrolytic Capacitors - When using Aluminum Electrolytic Capacitors please observe the following points to ensure optimum capacitor performance and long life

Series Connection of Electrolytics - When connecting electrolytics in series choose capacitors of the same voltage and capacitance rating and parallel the capacitors with an inter-connected resistance voltage divider in order to insure equal distribution of voltage between the capacitors

Capacitor markings

There is difference how different capacitors can be marked Large capacitor have usually the value printed plainly on them such as 10 uF (Ten Micro Farads) Many mall disk types along with plastic film types often have just 2 or three numbers on them First most will have three numbers but sometimes there are just two numbers These are read as Pico-Farads An example 47 printed on a small disk can be assumed to be 47 Pico-Farads (or 47 puff as some like to say)

Here is short introduction to markings you might see on circuit digrams

1 F = 1 Farad 1 mF = 1 milli Farad = 11000th of Farad or 001 Farads 1 uF = 1 micro Farad = 11000000 of Farad or 0000 001 Farads (10-6 ) 1 nF = 1 nano Farad = 11000000000 of Farad or 0000 000 001 Farads (10-9) 1 pF = 1 pico = 11000000000000 of Farad or 0000 000 000 001 Farads (10-12)

Sometimes you might see combination markings like 1n5 where decimal dot is marked with letter Here 1n5 means 15 nF In the same way 2p2 means 22 pF This is a common practice by some manufactures and the reason for this is quite simple By putting the letter in place of the Tiny Decimal Point it eliminates the chance of missing it on a poorly photo-copied or printed copy of a schematic

Capacitor color codes How to read Capacitor Codes - how to read number codes on small plastic film capacitors

Capacitor technical details

Capacitors and ESR Effective Series Resistance Ceramic capacitors in dcdc-input filters OK but watch out for those transients - Designers now

have new reasons to use ceramic rather than tantalum capacitors But be careful Considerations for a High Performance Capacitor Capacitors in Real-World Applications Electrolytic Capacitors - Theory Construction Characteristics and Application Evox Vifa Tech Notes - lots of details on capacitors Picking capacitors - capacitor testing article from Audio Magazine February and March 1980 Ultracapacitors deliver jolts of power - Ultracapacitors capable of storing vast amounts of

Electronics Basics

electrostatic energy can supplement or even supplant batteries in many applications Understanding the Parasitic Effects In Capacitors

CoilsAn typical inductor is simply a coil of wire which can be wrapped around either air or metal cores As current flows into an inductor a magnetic field is created around the coil When the current stops the magnetic field collapses generating an induced current flow in the coil Low frequency currents flow easily into the inductor but as the alternating current frequency increases the impedance of the inductor increases The inductor introduces a phase shift to AC signal going through it Inductors allow direct current to flow but as the frequency of oscillation increases so does the inductorrsquos impedance

A coil (of any sort) is an inductor Inductors behave to electricity as mass does to a mechanical system Inductors resist change in current flow just as masses resists change in physical movement Stand in front of a moving car and try to stop it its mass keeps it going

In the same way if you suddenly try to stop the current flowing in an inductor - the inductor will resist the change in current The same way the mass of the car resisted the mechanical stopping so will the inductance of the coil resist the stopping of the electrical movement - the current flow

An inductor is an energy storage device It can be as simple as a single loop of wire or consist of many turns of wire wound around a special core Energy is stored in the form of a magnetic field in or around the inductor By placing multiple turns of wire around a loop we concentrate the magnetic field into a smaller space where it can be more useful When you apply a voltage across an inductor a current starts to flow It does not instantly rise to some level but rather increases gradually over time The relationship of voltage to current vs time gives rise to a property called inductance The higher the inductance the longer it takes for a given voltage to produce a given current

Whenever there is a moving or changing magnetic field in the presence of an inductor that change attempts to generate a current in the inductor An externally applied current produces an increasing magnetic field which in turn produces a current opposing that applied externally hence the inability to create an instantaneous current change in an inductor This property makes inductors useful as filters in power supplies

All inductive devices operating in dc circuitry which are switched on and off should have a diode or other suitable protection component connected across their coils to catch the inductive fly back

Most simple coils are air-core coils They consists just winded copper wire Air-core coils can produce stable inductance over wide range of DC bias currents and work up to very high frequencies The biggest downside od air-core coils is that very many turns are needed to produce large inductances Other downside is that they produce somewhat large magnetic fields around them

Larger inductance coils can be produced by usign suitable magnetic material core With this approach large inductances are possible Many types of cores are commonly used in inductors magnetic material in coil core tends to concentrate the inductorrsquos magnetic field inside the core and increases the effective inductance While a magnetic core can provide greater inductance in a given volume there are also drawbacks A magnetic core can contain only a limited magnetic field The limitations of the cored coils are the usually limited operating frequency range and possibility of core saturation because of excessive AC current or large DC current All those characteristics depend on core material characteristics ans coil design and coil core type Toroid inductors minimize the magnetic field around the coil

General

Electronics Basics

Basic Inductor Theory - An inductor is an energy storage device It can be as simple as a single loop of wire or consist of many turns of wire wound around a special core Energy is stored in the form of a magnetic field in or around the inductor

Ferrites for RFI - ferrite toroidal cores as well as beads can be very useful in attenuation of unwanted RF signals

Frequently Asked Questions About Magnetic Materials And Their Answers - It is recognized that courses in magnetic materials and their applications are limited in university offerings Engineers who are getting into designs that require knowledge in this area often have questions about the science of magnetic materials and the variety of materials and geometries that are available MAGNETICS has compiled this document for the benefit of those seeking answers to some of the most commonly-asked questions

Inductive flyback catching diodes - All inductive devices operating in dc circuitry which are switched on and off (whether by a contact or by electronic circuitry) should have a diode connected across their coils to catch the inductive fly back

Introduction to Inductance The ABCs of integrated Ls and Cs - RF circuits need low-loss and high-Q passives for integration

Coil making and design

Air Core Inductor Calculator - If you are building your own cross-over network youll find that the inductors used most frequently for high powered systems are simply large coils of wire You might be able to save some money by winding your own This program calculates you how to build air core coils needed in audio systems (in millihenries range)

Coils - how to calculate coil inductance CWS ByteMark products and how to use them - This page has tips and data on various ferrite

materials Some of the products also known with Amidon name Designing air core inductors Design Formulas - for magnetic components Designing Extended-Range Toroidal Inductors - how to design coils for tens of MHz frequency range Eight Magnetic Axioms - Careful consideration of these axioms will clearly show the causes of

leakage and fringing flux Formulas For Magnetic Circuits - Electromagnetic Relationships and Formulas Impedance Properties for Select Materials - Information on characteristics of one turn verrite core

coils Inductance Calculation Techniques Approximations and Handbook Methods Iron Powder Cores from Amidon - information on products and equations for calcuating the turns

needed for coils Power considerations - how large a core is needed to handle a certain amount of power Practical Construction Tips For Coils Using Iron Powder Cores RF-inductor modeling for the 21st century - The familiar three-element model of an inductor has

some serious shortcomings even at frequencies well below the inductorrsquos self-resonant frequency A more useful model correctly predicts an inductorrsquos behavior over a range of frequencies

Software from Magnetics - some design software The 7-Henry Inductor - measured value of a large iron-core inductor can vary from its nominal

value for several reasons Toroid Calculation - This page explains how to calculate toroid coils

Toroid coil winding

Some useful hints concerning toroid winding Toroid Winding for the Dexterously Challanged

Electronics Basics

TransformersTransformer is an integral component of the power supply that pulls power from the wall outlet and transforms it or makes it into power that can be used by the electronic device The transformer outputs its power as alternating current as it receives power from the wall outlet In power supply application this output is sent to the rectifiers in a power supply that change the alternating current to direct current

A transformer transfers AC signals only by means of a magnetic field at low loss A transformer consists of two separate coils which have overlapping magnetic fields so that current flowing in one circuit is coupled to the other Often transformers consist of an iron core with two or more coils which couple magneti-cally Transformers are used to get voltage gain (at the expense of current reduction) and to step down power line voltages for power supplies Transformers are also used to match impedances between devices and to provide ground isolation

A typical transformer is layer wound on transformer core (usually so called E core) A layer-wound coil consists of single layers of wire separated by layers of insulation Here the insulation serves a dual purpose it is a support platform for the wire and electrical isolation from other transformer parts made of conductive materials (ie core other windings)

Nowadays also so called planar transformers have became popular in many pulse transformer and switched hode power supply applications Those planar transformers use typically a low-profile E-core ferrite core which mounts on the board and lets you use board tracks for windings of magnetic components such as transformers and output chokes in power supplies and chargers This kind of planr transformers are typically designed to operate at around 200 kHz to 15 MHz frequency

Transformers are not ideal devices Transformer have losses (typically 5-20 depending on design) when they operate Those losses heat up the transformer Lets pick up a normal mains power transformer as an example There are two kinds of major losses copper losses and iron losses Copper losses are the losses which are caused by the wire resistances in the transformer primary and secondary Copper losses are related to wire resistance (wire thickness) and the current trough the wire The losses increase to the square of the current travelling through transformer Iron losses are generated in the transformer core material (iron in mains transformer) due magnetic reluctance induced current circulating in the core and magnetic leakage Iron losses on transformer core are proportional to the voltage fed to the transformer primary (quare to voltage) The operating frequency does not effect the copper losses but it has effect on iron losses (higher frequency gives higher losses) Generally iron losses dominate the losses when transformer is not loaded and copper losses dominate the transformer losses when the transformer is heavily loaded

In high frequency transformers the effects descrbed above are the same In addition to effects above you need to take into account the skin effect in the wires and the capacitive losses in the winding

General

Basic Transformer Theory - This is a very short introduction to transformer theory Glossary of transformer terms Isolated Transformer vs Auto Transformer - There have been many questions about which is

better and why The easy answer is it depends on the application but lets look at a few details Piirilevymuuntajat - This document has some example pictures how you can mount a circuit board

transformer to a circuit board The text of this document is Finnish The Basics of Calculating Transformer Currents Trasnformer Hum - Very few systems are dead quiet There are usually always a few hum related

problems If your system has a bit of hum is it the transformer or not And what you can do about it

Electronics Basics

Transformer Polarization - performance characteristics of any ferromagnetic transformer will be dependent od its previous magnetic history pdf file

Transformers - basic definitions and information on specifications Varnish The Invisible Insulator

Transformer design

Transformer design needs knowledge and testing Magnetics parts are frequently misunderstood and almost always made out to be much more difficult than they really are Good magnetics design does NOT need a lot of complex analysis The problem is that there are so many variables to deal with and so many small details to know Like many other aspects of power electronics these details are seldom written down in an accessible form

Design Parameters for Low-Distortion and Power Transformers using EPCOS TTPR Cores - application note about ferrite core transformer design from Epcos in pdf format

How RF Transformers Work Leakage Inductance vs Winding Splits - information on providing specific amount of leakage

inductance into tranformer using windong splits pdf format Myths amp Misconceptions About Transformer and Inductor Design Output Transformer Design and Winding Program Quickly Calculates Transformer Design Parameters - a handy C program that provides

quick calculations for almost any type of transformer design parameters on-the-fly Ring Cores - application note about ferrite core transformer design from Epcos in pdf format Roll Your Own Power-Transformers - 20 page booklet on building power transformers The Transformer Book - A good book with lots of transformer design information Transformer calculation program - Transformer Calculation is program for calculating number of

coils and wire thickness at mains transformer If you have some experience in assembling transformers then this program is for you

Transformer testing and measuring

Determining Output Transformer Impedance - When replacing the audio output transformer on a radio the replacement should match the impedance of the original as close as possible If the wrong transformer is used the results can be low output and loss of tone quality

Dielectric Strength - information on Hi Pot testing of transformers pdf file Reverse Engineering an Output Transformer - Nondestructively - What simple tests can be done to

capture the specs of a vintage output transformer You may not be able to fully blueprint the iron through any simple calculation but you might be able to then provide some spec to produce another

Rhombus Industries Application Notes and General Information - information on tranformers and transfromer testing

Monitoring The Primary Current - Two methods to monitor the transformer primary current are described in this document

Transformer impedance measurements Transformer Insertion Loss and Frequency Response Measurements - pdf file Transformer Resistance and Inductance Measurements - pdf file

Transformer modeling

Model a nonideal transformer in Spice - how to model transformers in circuit simulation programs

Electronics Basics

Pulse Transformer Equivalent Circuit - pdf file Transformer Modeling Tips - technical note in pdf format from Midcom

Audio transformers

A transformer is an electrical device that allows an AC input signal (like audio) to produce a related AC output signal without the input and output being physically connected together This is accomplished by having two (or more) coils of insulated wire wound around a magnetic metal core

Audio transformers are used in many audio applications where signal needs to be converted (balanced-unbalanced converting) isolated (audio isolation transformers) or impedance needs to be converted (impedance conversion transformers tube amplifier output transformers) Audio transformers can

Step up (increase) or step down (decrease) a signal voltage Increase or decrease the impedance of a circuit Convert a circuit from unbalanced to balanced and vice versa Block DC current in a circuit while allowing AC current to flow Electrically isolate one audio device from another Convert an unbalanced signal to balanced signal and vice versa Block Radio Frequency Interference (RFI) in some applications

Unity 11 transformer often called an isolation transformer has the same number of windings on each coil As the impedance is identical for the primary and secondary the signal level does not change A unity transformer allows an audio signal to pass unmodified from the primary to the secondary while blocking DC voltage and radio frequency interference (RFI) Also since the primary and secondary are insulated from each other a unity transformer will electrically isolate different pieces of equipment This can solve hum problems by isolating (lifting) the grounds of different devices Other unity transformer applications include providing multiple outputs from a single mic input by using multiple secondary windings and changing balanced signals to unbalanced signals or vice-versa

In a step-up step-down transformer the primary and secondary have a different number of windings thus they have different impedances Different impedances cause the signal level to change as it goes through the transformer If the secondary has a higher impedance (more windings) than the primary the signal level at the secondary will be a higher voltage than at the primary Many microphones have step up or impedance matching transformers at their output

In audio application the transformers are generally divided to two different groups output transformers and input transformers Most simply stated output transformers are used at the low impedance or driven end of a balanced line and input transformers are used at the high impedance or receiving end The technical requirements and as a result the designs and physical constructions of the two transformer types are very different

An OUTPUT transformer is driven by an amplifier and typically loaded by several thousand pF of cable capacitance plus the 20 koh of a bridging line receiver An output transformer must have a low output impedance especially at high frequencies This requires low DC resistance windings and very tight magnetic coupling since the sum of the winding resistances and the leakage inductance resulting from imperfect coupling are effectively placed in series between amplifier and load To maintain the impedance balance of the output line the transformer must also have balanced output capacitances

An INPUT transformer is driven by the balanced line and is typically loaded by the input of an amplifier stage Its primary must have a high impedance to the differential voltage between the lines and this requires more turns of smaller wire producing relatively higher resistance windings The transformer must also suppress any response to the common-mode voltage A Faraday shield connected to ground is used to prevent capacitive coupling of the common-mode voltage from primary to secondary Sometimes also a

Electronics Basics

thin copper foil between windings is also used to reduce magnetic coupling

Audio transformer have their limitartions The first limitation is frequency response By design audio transformers only pass audio signals Therefore an audio transformer will block signals that are below or above the audio range of 20 - 20000 Hz This can be a limitation or a benefit depending on the situation A second limitation is that audio transformers have a maximum input level that cannot be exceeded without causing a distorted signal When the maximum level is exceeded the transformer is said to be saturated ie it cannot hold any more signal A third limitation is that audio transformers cannot step up a signal by more than about 25 dB when used in typical audio circuits

The insertion loss of a transformer is simply a measure of the efficiency It shows how power is consumed by the transformer The result is the temperature rise or how hot the transformer gets The majority of the losses are the DC resistance in the windings However the core loss can be quite high if the flux density is great

The impedance specification of audio transformers seems to confuse many engineers Although they tend to produce optimum results when used with specified external impedances the transformer itself has no intrinsic impedance Audio transformer impedancs is really no more than a label which can be attached to a transformer or a winding

A transformer simply reflects impedances modified by the square of the turns ratio from one winding to another Keeping in mind that input and output power are equal (minus the losses in transformer) If you measure the impedance of the primary winding you will see the reflected impedance of the load you connect to the secondary winding Reflected means multiplied by the turns ratio squared Transformer simultaneously reflects two different impedances One is the impedance of the driving source as seen from the secondary and the other is the impedance of the load as seen from the primary

Power transformer design is a pure math science audio transformer design is a creative art The physical size of both audio transformer designs are dependent upon the lowest frequency and the power available at that frequency If you choose a low end frequency of 50Hz and then pump heavy 30 Hz signal into the transformer you may develop a transformer saturation condition and the amplifiers will see a shorted output

Answers to common questions about audio transformers - application note from Jensen Transformers in pdf format

Audio Transformers - an introduction by Shure Audio Transformer Design Philosophies Audio Transformers Magnetic Shielding - After selecting the proper transformer for your

application the next consideration is the amount of magnetic shielding required for the particular end use

Audio Transformers Technical Issues - Audio transformers are real devices that obey all the laws of physics To use them properly you should have some idea of these laws and what it means to you the user This will not be a college course in electronics engineering - rather a simple explanation of the factors that will allow the user to obtain the best performance out of these devices

Frequently Asked Questions on Audio Transformers - describes transformer impedance impedance matching inductance and decibels

How to calculate transformer related noise figure - pdf file LF transformers - theory and some practice Output Transformer Design and Winding Phase Balance and the Mysteries Reverse Engineering an Output Transformer - Nondestructively - What simple tests can be done to

Electronics Basics

Tek-Notes Technical notes on audio and power transformers The Lundahl Transformer Production Process - this gives brief description of the steps involved in

manufacturing of tube amplifier transformers pro audio C-core transformers pro audio lamination transformers and emorphous core transformers (video transformers)

What is a Good Audio Transformer Winding arrangement of output transformers - windings of many output transformers can be

arranged in different ways to get best performance for different cases

RF transformers

RF transformers are widely used in electronic circuits for maximum power transfer impedance matching signal voltage level matching DC isolation and balancedunbalanced interfacing RF transformers are generally used for signal isolation for balanced-unbalanced conversion for signal level conversion and for impedance conversion in RF applications

Essentially an RF transformer consists of two windings linked by a mutual magnetic field By designing the number of turns in the primary and secondary windings any desired step-up or step-down voltage ratio can be realized Mutual coupling is accomplished simply with an air core but considerably more effective flux linkage is obtained with the use of a core of iron or ferromagnetic material with higher permeability than air

The basic phase relationship between the RF signals at the transformer input and output ports may be in-phase 0 degrees or out-of-phase 180 degrees

In some applications there is a need to pass a relatively high DC current (or low frequency AC) thrugh primary winding In this case the transformer core may saturate resulting in reduced transformer bandwidth and power handling capability For this type of applications special transformers that can handle the needed current must be used

How RF Transformers Work - This document describes how RF transformers work and how they are measured

RF BALUNs - one f the most important components in of transmitting system is the antenna feeder system

RF Balun Transformers - This application note is designed to help the reader understand how balun transformers can be used in todays RFMicrowave connunication applications

RF Transformers Questions and Answers - This document gives an introduction to RF transformers and answers many common questions

Transmission Line Transformers - theory articles and construction details for RF transmission line transformers check also how to design other ratios than 11 and 14

Telecom transformers

Transformers are very much used in telecommunication devices The most common use for a transformer is to form the galvanic isolation between the terminal equipment and the telephone line Transformers are used in this applications in almost any equipment which connects to a telephone line and to mains power (for example in modems ISDN cards ADSL cards etc) Most often used signal isolation transformer in telephone line application is 600600 ohm telecom isolation transformer In addition to signal isolation transformers are also used for signal balancing (balun) impedance conversion (matching different impedance signal lines) and they were commonly used to build telephone hybrid circuits in older telephones

Caging Transformer EMI Still a Key Design Issue - medical and telecom specs demand a quiet

Electronics Basics

electromagnetic setting Everything you wanted to know about wideband low-frequency transformers - Wideband low-

frequency transformers are useful components in various passive circuits such as the return-loss bridge

Ideal transformers aid in balanced-line analysis - Transmission-line transformers combined with appropriate resistor values are useful in hybrid applications over limited bandwidths One such device the 180deg hybrid combiner is useful in CAD analysis for verifying the performance of balanced and differential circuits The completed transformer provides matched signal levels 180deg phase-shifted and all ports at an impedance Z0 You dont need transmission-line transformers in the construction of this hybrid for analysis Instead the circuit uses an ideal 1-to-1 transformer Combined with the appropriate termination resistor and one additional transformer an ideal differential-excitation source is available

Midcom Technical Note Index - lots of technical notes onm telecom transformers

Transformers for switched mode power supplies

The switching mode power supply contains a transformercoil and to make this as small as possible the internal switching frequency has to be quite high something typically in the range between 20KHz and 1MHz

Controlling EMI in Transformers and Switch-Mode Power Supplies Design Parameters for Low-Distortion and Power Transformers using EPCOS TTPR Cores -

application note about ferrite core transformer design from Epcos in pdf format Isolated innovation marks movement toward miniature magnetics - hampered by fundamental

physical limits and manufacturing constraints the magnetics industry is slowly joining the trend toward surface-mount designs

Leakage Inductance Living With Leakage Elements in Flyback Converters - review of the magnetic and electric models of the two-winding and three-winding transformers

Parasitic Capacitance Effects in Step-Up Transformer Design Power considerations - how large a core is needed to handle a certain amount of power Spreadsheet simplifies switch-mode power-supply flyback-transformer design - designing flyback

transformers for switch-mode power supplies involves many calculations this spreadsheet helps it

Pulse transformers

Pulse transformers are generally used in singal isolation applications to pass signal pulses Most common application for pulse transformers have been isolated triggering of thyristors and triacs

Pulse Transformer Equivalent Circuit - pdf file

Current transformers

When measuring high currents on mains cables devices called current transformers are used Their main purpose is to produce from the primary current a proportional secondary current that can easily be measured or used to control various circuits The primary winding is connected in series with the source current to be measured while the secondary winding is normally connected to a meter relay or a burden resistor to develop a low level voltage that is amplified for control purposes In many high current applications the primary coil is just wire going through the toroidal core of the current transformer (=equivalent to one turn primary coil) When using just one wire going through the core that wire can easily made thick enough to be able to handle large currents Current transformers are relatively simple to implement and are passive devices that do not require driving circuitry to operate The primary current

Electronics Basics

(AC) will generate a magnetic field that is coupled into a secondary coil by Faradayrsquos Law The magnitude of the secondary current is proportional to the number of turns in the coil which is typically as high as 1000 turns or even more

The secondary current is then sensed through a sense resistor to convert the output into a voltage The voltage measured over selected burden resistor resistor connected between the current transformer output coil outputs gives the indication of the current (voltage directly proportional to the current) The selected burden resistor value is usually defined with help of transformer data and experimenting When a suitable burden resistor value is selected a general (experimental) transformation ratio is calculated for this application (ratio from input current to output voltage with given current transformer and burden resistor)

In some SMPS designs current transformer (usually made using a ferrite toroid) helps to track the current in the control circuits feedback loop This current is then used to determine how the future behavior of the SMPS will be modified

Many clamp-on multimeters and clamp-on current measuring adapters that can measure AC current are built as current transformers A simple current adaptor can only consist of the transformer core (which can be opened) the transformer secondary coil and suitable burden resistor

A current transformer design - This document describes how to design a current transformer Current transformers how to specify them Current transformers specification errors and solutions Current Transformer Design and Theory Field Adjustment of Current Transformer Ratio The Transformer Book - A good book with lots of transformer design information including current

transformers

High voltage transformers

Neon Transformer Dismantling Repairing - The transformers that are used to convert mains voltages to those suitable for powering neon signs are commonly used for the power supplies of tesla coils

Winding transformers

Winding Rod and Toroidal Transformers - some useful tips

Transformer applications and circuits

Isolation transformer passes millihertz signals - this circuit allows to successfully use an ordinary low-cost line transformer as an isolation transformer in ac circuits that require floating sources with this circuit the low-end frequency response extends below 100 mHz

Mains power transformers

Power transformers are available in a variety of configurations primarily determined by the type of core selected For the most part they boil down to one of two types EI laminations and tape- wound toroidal cores The tradeoffs involved in selecting one over the other usually include cost circuit application

Electronics Basics

weight efficiency shape and volume Regardless of which type is chosen the electrical function is the same one or more electrically conducting coils coupled together through magnetic induction

All power transformers should have approved insulation systems suitable for the users application A transformer with an inadequate insulation system can be a potential fire hazard National and regional transformer requirements and specific applications require the system manufacturer to be aware of the appropriate standards One important IEC document is IEC 950 which consolidates the requirements in the former IEC 380 (Safety of Electrically Energized Office Machines) and the former IEC 435 (Safety Data Processing Equipment) IEC 950 is embodied in several other national and regional standards including UL 1950 (US) EN 60950 (European Community) VDE 0805 Part 100 (Germany) BS 16204 (UK) and CSA C222950 (Canada) In general the major portions of these individual standards are the same as IEC 950

Many modern transformers nowadays in use in Europe are designed according standard EN 60742 (similar to IEC 742) EN60742 is based on the International standard IEC 742 which is also known as BS3535 in the UK and VDE 0551 in Germany It is the CENELEC standard for Isolating Transformers amp Safety Isolating Transformers Other inportant newer standard is IECEN 61558 - 1 Safety of power transformers power supply units and similar This standard has the following subparts

IEC 61558-2-1 separating transformers for general useIEC 61558-2-2 control transformers for general useIEC 61558-2-3 ignition transformers for oil burnersIEC 61558-2-4 isolating transformers for general useIEC 61558-2-5 shaver transformers and shaver supply unitsIEC 61558-2-6 safety isolating transformers for general useIEC 61558-2-7 transformers for toysIEC 61558-2-8 bells and chimes transformersIEC 61558-2-9 transformers for Class lll handlamps incorporating tungsten filament lampsIEC 61558-2-10 high insulation level transformers with working voltage above 1000 volts

A transformer which has to be inherently short-circuit-proof as per IEC 61558 is constructed without protection This kind of transformer can withstand short circuits without damage Usually only some very low power transformers are dsigned to be this type

A non-inherently short-circuit proof transformer as per IEC 61558 is equipped with a cutout to protect against short-circuit and overload In this case the transformer should be equipped with a thermal cutout This is propably the most often used transformer type on loaw power and average power applications (normal appliances)

There are also transformers which are not short-circuit-proof as per IEC 61558 and not equipped with a cutout When slling this kind of transfoerm the manufacturer is obliged to inform the user of the required safety measures by means of which the transformer must be protected in operation In this case the transformer should be protected by means of a miniature fuse as per IEC 127 the type and current rating of the fuse must be stated on the transformer label

Typical mains power transformers have around 90 effiency (some small ones have worse and some very large one have usually better effiency) Transformers are also designed for different operating temperatures Usually the rating of temeprature is based on the IEC 85 norm which defines the temperature ratings of insulation materials

Y = 90 degC A = 105 degC E = 120 degC B = 130 degC F = 155 degC H = 180 degC 200 = 200 degC

Electronics Basics

220 = 220 degC 250 = 250 degC

Doughnut shaped transformer commonly used in high quality electronics and amplifiers in particular for its low noise low resistance to current flow and power output for its size Toroidal mains power transformers are generally made with tape wound cores and high frequency toroidal transformers use generally ferrite core The tape wound cores provide an almost perfect magnetic circuits to minimize losses fringing leakage distortion and provide good magnetic shielding It also decreases the magnetization force required to produce a given flux density It is much more efficient than E-type lamination cores but will have somewhat higher cost as the windings need to be done on the core itself Toroidal transformers generally weigh around a pound for every 30 watts of output they can produce Thus a toroidal transformer capable of outputting 600 watts would weigh around 20 pounds

For transformers with power ratings less than 1 kVA the trend has been away from layer-wound to bobbin-wound coils A bobbin-wound coil has layers of wire precision-wound on a rigid form Most typical power transformers are constructed either as traditional E-core transformers and toroidal transformers

The main problem in equipment powered by a transformer is overheating due to excess current Typical causes of excess current are a short-circuit in the load connected to transformer or too much load connected to the transformer The result can lead to smoke fire burned wiring and connectors unless the transformer is protected agains this kind of occurence Typical protection methods are use of fuse (primary side and possibly on secondary side) overtemprature fuse inside tranformer or other similar overvoltage protection methos Typically the transformer primary fuse is used as the protection against short circuits in transformer (the fuse must generally be rated to have few times higher amperage than the transformer power would indicate to be able to handle the transformer start-up surges that can be quite hige especially with toroidal transformers) If transformer needs to be accurately protected against overload with fuses fuses rated per transformer power are usually needed on transformer secondary size Nowadays many modern transformers have internal overheating protection fuse to protect the transformer agains dangerous heating (caused by poor ventialtion or overload)

If the output of a mains transformer is short circuited then quite high currents can be seen on secondary of the transformer (up to many times the transformer power rating) In short circuit situation the secondary current is limited by the impedance of the transformer In most pratcial cases the maximum secondary current is limited almost only by the primary and the secondary coils resistances The saturation of the core will not occur under short circuit conditions (the core flux will be roughly half normal or lower)

Applying too high input voltage to a mains transformer will cause more than normal magnetig flux on the transformer core If there is enough material in the core to keep it from saturating it will Once the core saturates the impedance of the primary will drop to a very low value the current through the primary will only be limited by the resistance of the primary and either the primary or the breaker will open This same thing can happen with the ratedp voltage of the mains frequnecy drops very much below rated frequency

In mains transformers there is always some capacitive coupling from the primary to secondary of the transformer A typical capaitance here is in range 10-100 pF This capacitance causes that some input signal leaks to the output coil (mostly as common mode noise) This capaictance cause some small leakahge current at mains frequencies to transformer secondary In some applications where even a small leakeage is undesired special transformer constructions are use Typical solutions to redice the leakege current are completely separate primary and secondary coil connected to each other only through a grounded transformer core or using an electrostatic shield between primaty and secondary coil (typically copper or aluminium foil)

General

How Transformers Chokes and Inductors Work and Properties of Magnetics

Electronics Basics

Toroidal Power Transformer Construction - This gives a general introduction how toroidal mains power transformers are constructed

Transformer Basics Transformer Facts Technical Bulletin No1 Application Notes on Rectifier Transformers Transformer Facts Technical Bulletin No2 International Line Voltages and Frequencies Transformer Hum - A mechanically induced hum or buzz is equally easy to determine Place

your ear very near to each piece of your electrical equipment and again listen for hum and buzz If you hear a hum or buzz emanating from within your equipment we would refer to this as a mechanically induced noise (as opposed to an electrically induced noise)

Calculation related to power transformers

How do we design a rectifier safety transformer for feed to voltage controllers of 5Vdc1Adc and 2x12Vdc01Adc with RC-load in accordance with IEC 61558 - This is one design example using RALE design problems

How should one design a low inrush current universal control transformer for 800VA continuous output power as per IEC 61558

Method of Determining Secondary Current Ratings in DC Circuits - This document gives you the equations for Half Wave Rectifier (HWR) Full Wave Center Tap (FWCT) Full Wave Bridge (FWB) and Dual Complementary Rectifies (DCR) Also example circuits are given This document gives also information how to add a regulator to the power supply output

Power Transformer Specification Formulae - calculated transformer needed for regulated linear power supply

RALE Design Examples How do we design a small transformer - information on designing mains power transformer using computer design software

Selecting transformer type

Specifying the Proper Transformer - international standards governing electronic equipment have specific requirements for transformers

Specifying shielding regulation and temperature rise Understanding Transformer Standards at Home and Abroad - standards in USA and

Internaltionally

Power supplies and transformers

Design Tips - information on transformer measuring and design and also general power supply design

Method of Determining Secondary Current Ratings in DC Circuits Power Transformer Specification Formulae - calculated transformer needed for regulated

linear power supply

Isolation transformers

Isolation transformers are often installed to isolate and protect sensitive expensive equipment from noisy electrical system grounds ground loops power line spikes and other power line disruptions

Many instances arise when it is desirable to incorporate an isolation transformer within an electronic product Usually the reason for this is increased safety or noise isolation This may be

Electronics Basics

desirable for special applications or designs such as a demonstration display or design prototype

Isolation transformers are also available as separate units Those are generally used in laboratory environment and dangerous environments to increase the electrical safety Sometimes isolation transformers are needed to fight against power line noise or ground induced noise in sensitive electronics systems

Isolation Transformers Increase Safety of Electronic Systems Isolation Transformer Makes Comeback Suppression of Powerline Noise with Isolation Transformers

Technical information

Piirilevymuuntajat - circuit board mounted transformer technical information in Finnish by Muuntosaumlhkouml

Rengassydaumlnmuuntajat - toroidal transformer technical information in Finnish by Muuntosaumlhkouml

Signal Transformer Technical Library - application notes and FAQ

Making own power transformers

Roll Your Own Power-Transformers - an article on transformer design and building

Toroidal transformers

There is no dramatic technical difference between a toroidal transformer and a conventional transformer The only main difference is the form of transformer In principle a perfect toroidal winding has no external magnetic field and in practice toroidal transformers do have lower external fields but transformer designers tend to design toroids to run closer to saturation which increases the external field largely eliminating the advantage If designed to do so a toroidal transformer can provide higher inductance tighter coupling higher efficiency and higher Q and on and on comapred to traditional transformer

Toroids are popular in hi-fi amplifiers because they allows claims about low external field and because the size of wound toroidal transformer is lower than than equivalent conventional transformer The squashed profile of the toroidal transformer also gives it more surface area per unit VA than a conventional transformer so it dissipate more heat per unit temperature rise which the designers exploit by running them at higher current density

There are two disadvantages associated with toroidal cores The first is price The nature of a toroidal core necessitates slower more complex winding techniques particularly for high-voltage or multi-output transformers The price differential is most significant for sizes up to 300 VA

High power (1500W and up) toroidal transformer can have a very high inrush current because of low air gap in transformer EI laminations offer inherently lower inrush current and the problem can be further reduced by introduction of an air gap into the construction This is far more difficult and expensive to do with a toroid It sometimes becomes necessary to add a resistor in series with a primary of a toroidal transformer to prevent destruction of overload protectors on turn-on

Electronics Basics

Magnetic materialsMagnetic materials are used in applications such as power supply transformers audio transformers AC and RF Filter inductors broadband and narrow band transformers damping network EMIRFI suppressors etc The basic characteristic of magnetic materials is the permeability (micro) It is a measure of how superior a specific material is than air as a path for magnetic lines of force (Air has a micro of 1) Another characteristic of magnetic material is saturation It is the maximum value of magnetic induction at a specified field strength When a material saturates it losses its linearity Magnetic materials are available in many different types and sizes

There are many different magnetic materials with different characteristics Laminated or tape wound cores are manufactured by using different steel grades with different widths and thickness wound in circular manner Tape wound cores have very high permeability and are used primarily in power transformers reactors in 60 Hz to 400 Hz DC to DC converters and current transformers

Iron powder cores are composed of finely defined particles of iron which are insulated from each other but bound together with a binding compound Iron powder cores are suitable for applications such as narrow band filter inductors tuned transformers oscillators and tank circuits

Ferrites are ceramics materials that can be magnetized to a high degree The basic component is iron oxide combined with binder compounds such as nickel manganese zinc or magnesium Two major categories of ferrites are manganese zinc (MnZn) and nickel zinc (NiZn) Ferrites can be manufactured to very high permeability (over 15000) with little eddy current losses However the high permeability of the ferrite makes it unstable at high temperatures and saturates easily (even could be damaged by high saturation) Ferrites are suitable for applications such as DC to DC converters magnetics amplifiers EMIRFI suppressors transformers and inductors Ferrite cores can be gapped to avoid saturation under DC bias conditions

Amidon Technical Reference Online - lots of information on magnetic materials Choice of core meterial - the choice of material is of prime importance if the expected results are to be

realised from any design using ferromagnetic cores Ferrites - Ferrite Cores are available in numerous and several permeabilities Ferrite suppression beads - used for decoupling (keeping out unwanted signals) on dc supply and some

signal lines and provide attenuation of selected frequency bands Ferrites from Amidon - information on products and equations for calcuating the turns needed for coils Ferrites for RFI - ferrite toroidal cores as well as beads can be very useful in attenuation of unwanted RF

signals How to choose permanent magnet materials and grades How Transformers Chokes and Inductors Work and Properties of Magnetics Frequently Asked Questions About Magnetic Materials Iron Powder Cores from Amidon - information on products and equations for calcuating the turns needed

for coils Magnetic amp Ferromagnetics Materials - This is a basic introduction to most commonly used Magnetic

materials are used in applications such as power supply transformers audio transformers AC and RF Filter inductors broadband and narrow band transformers damping network EMIRFI suppressors

Magnetic Properties of Metal - which metals are magnetic and which are not Power considerations - how large a core is needed to handle a certain amount of power Practical Construction Tips For Coils Using Iron Powder Cores Thermal Expansion for Magnetic Metals Use Of Ferrites In EMI Suppression Using ferrites for interference suppression Using the data tables od iron poweder toroids - describes basic ferrite material types theur main

Electronics Basics

parameters and coil design

Special electromagnetic components Electromagnetic Delay Lines

SensorsLots of sensor information can be found at Measuring technology page

RelaysA relay is a remotely controlled operated switch it consists of one or more contact pairs that serve to open close or transfer external circuits The relay is just a switch activated by electricity A relay is a simple electromechanical switch made up of an electromagnet and a set of contacts

Relays usually have several contacts A common type is Dual-Pole Dual-Throw which means that it has two sets of contacts and that both sets have two positions For each set there will be a common line and one which is normally connected to the common line (when power is off) and one which is normally open

If you supply power to the coil (at rated coil voltage) the relay will engage and the normally open contact will be connected to common If you connected the live wire to the common pin and the load (VCR TV) to the normally open pin then it would go on when you supplied power to the coil

The industries using relays are many and varied Designers often use relays as electrically controlled switches In a relay the switch contacts are electrically isolated from the control input which is a very useful feature on many applications So called light duty electromagnetic relays are used in applications like communication control monitoring or alarm switching circuits in which load currents are normally fractions of an ampere to 25 amperes Relays are very much used in automotive applications and mains switchign applications where considerable currents needs to be switched Relays are also used for analigue signal switching (hifi equipment measurement devices) telecommunications application (telephone line onoff hook relay) and for RF signal switching (special coaxial cable relays)

Relays are available with AC and DC coils for various voltages (uaually anythign from few volts of DC up to 230V AC) The most common form of actuator or motor system for electromagnetic relays consist of an energizing coil and a permeable iron circuit It has both a fixed portion (open loop) and a movable member called the armature that completes the magnetic circuit by closing the air gap The movement of this armature causes the contacts of the controlled circuit to perform a switching function A typical relay has a spring for the return stroke and for holding selected contacts closed when the relay coil is in the de-energized Typical specifications you get from a DC relay coil is the coil resistance and intended operation voltage (typically voltage range) Coil resistance specifications are typically given for an ambient temperature of 25deg C The coil operation voltage should be checked because lower than minimum operating voltage will not reliably operate the relay and higher then rated voltage can damage the relay (typically heats the coil too much)

When using DC relays please note that relay coils can generate quite high self-induced voltage when the relay is switched off Because this voltage can damage electronic components like switchign transistors typically protective components are used to avoid it (most typically used component is a reverse-polarized diode in parallel with the relay coil)

AC relays need somewhat specific constructions Shaded pole AC relays are generally constructed like simple DC

Electronics Basics

electromagnetic relays with a portion of the core pole face separated from the rest of the pole face and enclosed in a loop of copper This loop produces a lag in the timing of the ac magnetic flux in one portion of the pole face with respect to that in the unshaded portion While the current in the coil passes through zero twice each cycle the flux in the armature gap remains at a high enough level to hold the armature operated

Dielectric ratings for relays are a function of size the separation between contacts and the separation between various parts of the structure The ability of a relay to withstand impressed voltage depends on the type of insulation employed and the severity of the in-service environment The periodic polarity reversal that is characteristic of ac voltages applies greater stress to most insulating material than does an equivalent dc voltage The result is that a given dielectric material will likely breakdown at a lower peak ac voltage than dc voltage Please note the relay voltage ratings when specifying the relay for a specific use

When switching electrical loads on an off using relays you must take into account the relay ratings The relay contacts need to withstand the current to the load (including potential high inrush current) and the switched voltage When selecting relay rationg please note that the current andor voltage ratings for relay contacts can be different for AC and DC switching applications When switching mains loads like electronic devices and lamps usually a large inrush current can go through relay contacs for brief time (can be easily up to 80A) If the relay contacts are not rated to handle the inrush current the relay contacts can be weld shut which means that the relay cannot switch off and is rendered useless

Relays have many good features but relays have also some downsides First thing is that many relays are mechanically quite large compared to very many other electronic component The relays have the power dissipation in a relay coil may render the device unattractive in battery-powered applications A relay coil is a highly inductive load which means than when driving a raly from electronics circuit you need to design the driver circuit such that it is protected against inductive kick-back when current to relay coil is stopped or you need to add extra protection diode in parallel with relay coil Because a relay is an electromechanical device it has limited life both in mechanical and electrical contacts The bouncing relay contacts can produce arcs that threaten system reliability can cause RFI problems and can be dangerous in some application

Power Relays or Contactors are used in industrial and military applications used for switching heavy contact loads that may be highly inductive such as motor generator and transformer loads These devices are also used to switch the heavy resistive and lighting loads Most typical use for contactors are motor starters Across-the-line industrial motor starters are made in sizes up to those capable of carrying 600 amperes Contacts of power relays used for motor control must be capable of opening at six to eight times the rated steady current in case a motor should stall Wattage dissipation is greater in these relatively large units than in the general purpose relay

Solid state relays (SSR) are the electronic equivalents of a mechanical relay with some notable advantages Solid state relay (SSR) and semiconductor relay are both names of relay like device which works like a normal relay A basic definition of a totally solid state relay is a device that operates a load circuit without the use of physical contacts This relay contains a transistor or triac which turns on a load circuit An SSR is a semiconductor device that can be used in place of a mechanical relay to switch electricity to a load in many applications Solid-state relays are purely electronic normally composed of a low current control side (equivalent to the coil on an electromechanical relay) and a high-current load side (equivalent to the contact on a conventional relay) Advantages of SSRs are quieter operation longer life and faster repetitive operations especially where counting or numerical operations are concerned SSRs are also more immunite to physical shock than electro-mecahnical relays (EMRs) Disadvantages are cost and higher currents may require external heat sink components

A typical SSR consists of an LED input which is galvanically isolated from an output switch circuit The output switch uses a photo diode stack to detect the LED optical signal and then drives a pair of common source power MOSFETs or one TRIAC which short or open the output depending on the state of the input This arrangement offers a number of important advantages over mechanical relays These include high input- output isolation as a result of the optical coupling high reliability because of the elimination of contacts immunity to magnetic field coupling and very small packaging SSRs are widely used in a number of applications ranging from modems to candy machines Triacs are used in relays ment for only AC operation FETs are used in relays which must be capable to switch AC and DC

Electronics Basics

Optoisolator Relay is a name for an electronics component most often just called optoisolator or optocoupler The optoisolator sometimes called an optocoupler is an assembly that contains a light emitting diode and a solid state photosensitive device These are placed in close proximity to each other so that light generated by the LED will be impressed upon the photosensitive device which may be a transistor SCR or triac that is normally non-conducting An input signal fed to the LED causes it to glow emitting light When the light energy is impressed upon the solid state device it becomes conductive allowing the output circuit to be energized Since the coupling medium is light the optoisolator can be designed to attain an isolation voltage rating of several thousands of volts

The types of contact loads to be considered in relay design may be divided into four broad categories (each category has different need for relay contacts)

1 Dry circuits By definition a contact is considered to be dry if it does not make or break current There are however many applications falling within this category in which contact may be required to carry appreciable current Dry circuits are usually considered to be loads that are not opened or closed by the contacts that is currents may flow through the contacts after closure and before opening but the contact does not directly control the load

2 Low level loads Low level switching ordinarily is considered to be in range of microamperes or a few milliamperes with the open-circuit voltage below the melting voltage of the contact material

3 Intermediate loads Intermediate contact loads are those for which the current is below the minimum necessary for a momentary arcing condition Fifty to 400 milliamperes at 26 Vdc is representative for this range In the intermediate load range slight arcing may occur on closure or opening of contact

4 Heavy loads in the so-called rated-load range Heavy contact loads are those that cause some degree of contact arcing under normal operation Ordinarily contact must operate at or close to the rated load function satisfactorily for their required life

There are several classifications of relays There are basically three types of relays a Form A which is normally closed Form B which is normally open and form C which is a Form A and Form B both triggered by a common input The Form C is widely used in telecommunications circuitry

There are also specific devices called relays which contain relay and other electronics

AnalogDigital Electromechanical Time Delay Relay is a device that provides a predetermined delay after power is applied before the contacts of an electromagnetic relay transfer This kind of device is typically constructed so that the electromagnetic relay is operated by a signal given by analog discrete components or digital-operated integrated circuits

A polarized relay is one that responds to the polarity as well as the magnitude of the energizing current One way of accomplishing this type of operation is by connecting a blocking diode either in series or in shunt with the coil of a conventional dc relay When the energizing voltage is of the correct polarity operation takes place as in a conventional relay with opposite polarity applied voltage there is no response

Thermal relay consists of a heater element a moving bi-metallic heated member and an actuating linkage that operates normally open or normally closed contacts Thermal relays are typically use dfor overcurrent protection (high current heats bi-metallic heated member and thus operates relay) Thermal relays typiclly provide operate time delays of 01 second to 5 minutes the operate time for a particular design being a function of adjustment and power dissipation or applied voltage

Overcurrent and earth fault relays are electrical network protective components which typically consists of switching current measuring and electronic controlling parts

Relay information

Advantages of Solid-State Relays Over Electro-Mechanical Relays - This is an application note from

Electronics Basics

Clare Engineers Relay Handbook Information - This reference material is reprinted with permission

from the Engineers Relay Handbook 5th edition published by the National Association of Relay Manufacturers (NARM)

How Relays Work - A relay is a simple electromechanical switch made up of an electromagnet and a set of contacts This document is a good introduction to relays

Interfacing switches and relays to the real world in real time - Designing the external interface to an industrial or automotive application can be challenging for an uninitiated systems engineer The bouncing of switch and relay contacts can produce arcs that threaten system reliability ESD can also threaten reliability and uptime Fortunately there are ways to ease the task of designing an interface between the inputs of a microcontroller and a hostile industrial or automotive environment

Relays 101 - introduction to car relays Relays solid state versus heavy metal - in many applications you have the choice between solid-

state relays (SSRs) and electromechanical relays (EMRs) this article can help you to make the right choise

Semiconductor relays - collect information about semiconductor relays and semiconductor relay circuits

Understanding a relays operation can prevent trouble down the line - venerable relay has undergone some changes in the past few years and you should understand the operation of these SSRs to get the best performance results

Relay circuits

Analog switch lowers relay power consumption - Designers often use relays as electrically controlled switches You can lower this dissipation by adding an analog switch that allows the relay to operate at a lower voltage

High-side driver has fault protection - High-side drivers find common use in driving grounded solenoid coils and other loads Short-circuit protection for such drivers is essential for avoiding damage from wiring faults and other causes Polymer fuses are generally too slow and discrete current-limiting circuits are large and cumbersome This circuit uses a small low-dropout linear regulator as a high-side switch and provides inherent current limiting and thermal shutdown

Relay circuits use reverse hysteresis - take advantage of the disengaging (off) threshold of the standard hysteresis curve

Relay driver saves substantial power - common practice to operate relays and solenoids at a reduced holding power once the mechanical actuation takes place

Solenoids Circuit drives 9V solenoids from 3V battery Simple solenoid driver reduces power and cost - solenoid valves commonly control the flow of low-

pressure gases and fluids in biological applications and a typical valve may operate at 12V and draw 1A Timer chip makes universal solenoid driver - 556 timer IC allows you to control the ratio of holding current

to peak current in a solenoid driver thereby overcoming the fixed-ratio constraint inherent in available solenoid-driver ICs

Switches

Electronics Basics

Circuit simulates contact bounce - simulates contact bounce of electromechanically and mechanically actuated electrical contacts

Contact Bounce and De-Bouncing Debouncing networks make reliable selector Different electronic switch types - This documents is a quick introduction to different switch types used in

electronics circuits Interfacing switches and relays to the real world in real time - esigning the external interface to an

industrial or automotive application can be challenging for an uninitiated systems engineer The bouncing of switch and relay contacts can produce arcs that threaten system reliability ESD can also threaten reliability and uptime Fortunately there are ways to ease the task of designing an interface between the inputs of a microcontroller and a hostile industrial or automotive environment

Switch Bounce and Other Dirty Little Secrets - there is a dirty little secret that every engineer learns soon after he or she tries to connect a switch or a relay to a digital system switches can do some really odd things if not used correctly

Switch chatter eliminator Switch De-bouncing Switch debouncer uses only one gate - This circuit produces a single debounced pulse each time you press

a button

Other electromechanic controls Rugged devices join the revolution in revolution - Electronics invasion of mechanical systems is increasing

the need for reliable cost-effective mechanical measurements Where theres rotation theres often a gear and where theres a gear theres-at least potentially-half of a noncontact rotary-motion sensor The other half is the fun part

DiodesDiodes are non-linear circuit elements Qualitatively we can just think of an ideal diode has having two regions a conduction region of zero resistance and an infinite resistance non-conduction region For many circuit applications this ideal diode model is an adequate representation of an actual diode

The behaviour of a (junction) diode depends on its polarity in the circuit If the diode is reverse biased (positive potential on N-type material) the current through the diode is very small A forward-biased diode (positive potential on P-type material) can pass lots of current through it would much resistance (only a small voltage drop)

Diodes are very often used in power supplies for rectifying applications A typical method of obtaining DC power is to transform rectify filter and regulate an AC line voltage In power supply applications it is common to use a transformer to isolate the power supply from the 110 V AC or 230V AC line A rectifier can be connected to the transformer secondary to generate a DC voltage with little AC ripple

There are several other types of diodes beside the typical junction diode The Zener Diode is a special diode where Zener breakdown occurs when the electric field near the junction becomes large enough to excite valence electrons directly into the conduction band This means that a zener diode passes current through it in reverse direction when voltage is high enough (the zener voltage) Zener diodes are typically used as voltage reference components in measuring circuits as voltage regulators in some low power power supplies and as over-voltage protection devices

Light-emitting diodes (LED) emit light in proportion to the forward current through the diode LEDs are low voltage devices that have a longer life than incandescent lamps They respond quickly to changes in current (many can easily go up to 10 MHz) LEDs have applications as visible indicators in devices and in optical-fiber

Electronics Basics

communication LEDs produce a narrow spectrum of visible )many colors available) or infrared light that can be well collimated

Light-Sensitive Diodes indicate light of a proper wavelength Photo-diodes or photocells can receive light signals LEDs and photodiodes are often used in optical communication as receiver and transmitter respectively

Diode Circuits Diodes - description of construction and operation of different diode types Diode VoltageCurrent Curves - Does a Specific Knee Voltage Really Exist Full Wave Rectification - This article describes how full wave rectification using four diodes works The Unusual Diode FAQ Variable capacitance diodes list - come commonly used types

Special diodes New Approaches For Designing High Voltage High Current Silicon Step Recovery Diodes for Pulse

Sharpening Applications Step-Recovery Diodes Specifications Step Recovery Diode Comb(Harmonic) Generators The Unusual Diode FAQ

Thyristor and TRIAC Explanation of Maximum Ratings for Thyristors - application note from Teccor pdf file Fundamental Characteristics of Thyristors - application note from Teccor in pdf format Gating Latching and Holding of SCRs and Triacs - application note from Teccor in pdf format Phase Controlling Using Thyristors- White paper in pdf format PUT Complimentary Feedback Pair - connect two transistors to make four layer device which works like

UJT or thyristor SCR versus Triac comparision - technical details of thyristors and triacs pdf file Teccor Application Notes - thyristor and TRIAC information

TransistorsAt their most basic level transistors may seem simple

There are three basic transistor circuits They are called according to that electrode (emitter base col-lector) which is common to both input and output circuit

When analyzing transistor in circuit simulation in mind a transistor can be considered as an active four-pole network When driven with small low-frequency signals its properties can be described by the four characteristic values of the h-matrix (hybrid) which are assumed to be real In the transistor data sheets the h-parameters are usually quoted for the common emitter configuration and for a given operating point (bias) Whereas the network behaviour of low frequency transistors could be described by using the h-matrix (hybrid) the y-matrix (admittance) is usually employed for high frequency transistors

Abridged Transistor Specifications - data of many common transistors A High Frequency Model for BJT

Electronics Basics

BJT Configurations - three basic ways in which a bipolar junction transistor (BJT) can be used is presented in this document

Consider IGBTs over power MOSFETs at frequencies to 100 kHz - evaluating the performance of IGBTs and high-voltage power MOSFETs for switching applications requires a common set of applications and assumptions

Coupling Circuits amp Techniques - how to interconnect transistor amplifier stages ESP-SEMI - a small program to find transistor data over 1400 transistor types listed includes also text

file format of the specifications Example Transistor Circuit - One of the most commonly used transistor circuits is voltage regulator

voltage follower How Transistors Work Kleinsignal Transistoren - data on some popular small signal transistors Transistor Biasing How a Transistor Works How Semiconductors are Made Martijn Beelens Transistor Page - most of the answers to questions about transistors ESP-SEMI - a small program to find transistor data over 1400 transistor types listed includes also text

file format of the specifications PUT Complimentary Feedback Pair - one of the most useful simple circuit configurations is this

connection of two transistors into a four layer device which can act like Programmable Unijunction Transistor Silicon Bilateral Switch Flasher Bistable Schmidt Trigger Thermostat Electric Field and Leakage Detector

RF Power Transistors - transistor comparision table RF transistors meet wireless challenges - Discrete RF transistors using a variety of processing techniques

are proving their mettle in the demanding world of wireless communications Shortform Transistor Database The internal functioning of a transistor Transistor Cross Reference Database - database currently has over 40000 transistors in it which can be

cross-referenced to other parts you can also download the whole cross reference list file by Pacific Semiconductor

Transistor h and y Parameters - A transistor can be considered as an active four-pole network When driven with small low-frequency signals its properties can be described by the four characteristic values of the h-matrix (hybrid) which are assumed to be real In the transistor data sheets the h-parameters are usually quoted for the common emitter configuration and for a given operating point (bias) Whereas the network behaviour of low frequency transistors could be described by using the h-matrix (hybrid) the y-matrix (admittance) is usually employed for high frequency transistors

Transistor Cross Reference Page - many common transistors listed Transistor History Transistor Pinouts - some common transistors in TO-92 case listed Transistors - to explain the transistors for beginners Transistors of the future Will diamonds be an engineers best friend - electronics industry will have to

start developing and using new materials and technologies to keep up with the increasing need for smaller faster transistors

Unijunction Transistors Why Bipolar - what is the future of bipolar transistor with competing technologies like CMOS

FETs IGBTsFET stans for Field Effect Transistor A regular FET pinches off (depletion mode) has input impedance around 1 megohm or more

MOSFET stands for Metal Oxide Semiconductor Field Effect Transistor It is one type of SET MOSFET (metal oxide

Electronics Basics

semiconductor) also known as IGFET (insulated gate) has a layer of insulation above a transistor junction A MOSFET can have very high input impedance up to around 1E12 ohm Most mosfets are enhancement mode (naturally off) MOSFET can give a true ohmic source-drain connection controlled by gate voltage

A good fit Power FETs find their place - Using packaging parameters app notes and reference designs low-voltage FETs power todays high-current designs

A simple guide to selecting power MOSFETs - As power-supply size and performance demands increase selecting the right switching devices becomes more complex A straightforward method simplifies the selection process speeds your development and helps you to optimize your design

Foolin with FETs - FET amplifier circuit ideas Gate Drive Techniques For Large IGBT Modules - efficient witching of these large IGBT modules requires

fast gate drivers with high peak output currents How a field effect transistor works IC maintains uniform bias for GaAs MESFETs - The gate-turn-on threshold voltage for GaAs MESFETs

(gallium-arsenide metal-semiconductor field-effect transistors) varies considerably from part to part even within a given lot That behavior makes biasing difficult especially if you want to design the device into a high-volume product To overcome this drawback you can introduce a current sensor that monitors the bias current and provides feedback to the gate input

IGBT Characteristics - info on Insulated Gate Bipolar Transistors Measuring HEXFETreg Characteristics MOSFETs and IGBTs differ in drive methods and protection needs Power Mosfet Basics - technial paper in pdf format check also Paralleling of Power MOSFETs Power MOSFET Basics - magazine article Protecting IGBTs and MOSFETs from ESD RF FET Small Signal Transistors Simple and inexpenesive methods to generate isolated gate drive supplies The Dos and Donts of Using MOS-Gated Transistors Transformer-Isolated Gate Driver Provides very large duty cycle ratios - information on driving power FETs

Unijunction transistorUnijunction transistor (UJT) is a special transistor like component which is used to build oscillators It was quite commonly used component in 1970s but nowadays quite rarely used

2N4871 UJT Unijunction Transistor - some example circuits for PUT Complimentary Feedback Pair - connect two transistors to make four layer device which works like

UJT or thyristor

Optoelectronics Agilent LED Selection Guides Applications of Optocouplers - basic optocoupler applications described pdf file The LED FAQ Pages What is Inside an LED

Crystals and crystal oscillatorsTypical crystal oscillates at the fundamental resonance frequency determined by the cystal mechanical characteristics (crystal material and crystal cut)

Electronics Basics

Many high frequency crystals (mostly those above 20 MHz) are overtone crystals which need special attention in the use to make them oscillate the nominal frequency and not the fundamental frequency Fundamental frequencies are approximately one-third one-fifth or one-seventh the overtone frequency depending on the cut of the crystal

Crystal and Clock Oscillator Technical Terms Crystal Oscillator Technical Articles Oscillators 101 What Every Engineer Should Know about Crystal Controlled Oscillators Oscillators for Communications Applications Basic Operation and Available Types Oscillator Theory of Operation - information on crystal oscillators Quartz Crystal Theory of Operation and Design Notes

RF components How RF Transformers Work Introduction to Directional Couplers Introduction to modulators - information on RF modulators Measuring the electrical performance characteristics of RFIF and microwave signal processing

components Mini-Circuits Application Notes Most Often Asked Questions About Electronic Attenuators Most Often Asked Questions About QPSK Modulators Most Often Asked Question About RF Limiters Most Often Asked Questions About Power Splitter Combiners Power Splitters - some power splitter ideas for antenna systems Understanding Mixers - general information on RF mixers and how to measure mixer performance Understanding Power Splitters Understanding VCO Concepts

Electromechanics Different electronic switch types What is a solenoid - solenoid information and troubleshooting

ConnectorsIn electronics connectors are one of those things we tend to take for granted Theyre just something hanging off the end of a cable so we can plug and unplug power or signals on some circuit Besides the obvious such as having the right number of pins there are several things to consider when choosing a connector cost ruggedness environmental protection signal type voltage rating current rating and connector available from many manufacturers

Connector Reference from AMP - nice set of connector drawings Connectors - Introduction to connectors and basic connectors described Measuring connectors - would like to replace one connector type with a different less expensive model

How do I prove the two connectors have the same electrical characteristics Also how will the power and ground-pin assignments within the connector affect its performance

Electronics Basics

Neutrik connectors assembly instructions Neutrik Connectors Cable Preparation and Wiring information - from Canford Audio

Fuses and similar protection devicesThe main job of the fuse is to protect the wiring Fuses should be sized and located to protect the wire they are connected to Circuit breaker or fuse is a protective device located on an electrical circuit to interrupt the flow of abnormally large currents

A fuse is a circuit element designed to melt when the current exceeds some limit thereby opening the circuit A fuse is the most common means of providing overload and fault protection for customers and utilities Fuse is a safety device so when operating with them be sure what you do When safety is involved you shouldnt be guessing

Fuses are the commonly used protection devices to protect components like wires transformers electronics circuit modules against overload The general idea of the fuse is that it burns fuse link when current gets higher than its rating and thus stops the current flowing

The most important ratings of suses used in electronics circuits are current rating voltage rating and interrupt capacitu

The current rating tells the current the fuse allows to pass through If the current gets higher then after some time the fuse link melts (the time this takes depend on the fuse design and the amount of current flowing) For safety reasons put only the fuse with the same current rating as the equipment indicates Putting a fuse with higher current rating than indicated will cause a serious safety hazard (fire hazard when more current gets through than the equipment is designed for)

The voltage rating of a fuse is to ensure that as the fuse link melts and then arcs that the arc extinguishes does not re-strike and that the fuse stays open The fuse voltage rating tells how much voltage the fuse can safely interrupt When replacing a fuse with a new one select a fuse type with at least the same voltag rating as the original one You can safely replace a fuse with a new one which has higher voltage rating than the old fuse

Issues related to the blast (fuse burning) are covered by the interrupting rating of the fuse which is the maximum current the fuse can interrupt at rated voltage without exploding or rupturing This interrupt rating is highly dependent on the voltage over the fuse and is the fuse operated at AC or DC So when checking the interrupt rating check under what conditions tose are defined for the fuse you use The interrupting rating is not the same as the fuse current rating Interrupt rating needs to be considered in the applications where high short circuit currents are possible (the fuse should reliably cut the current in those cases also)

In addidion to those you might sometimes see additional fuse parameters like fuse speed or arching time Those define how quickly the fuse cuts the current in the case of overload

There are also some other type of protection devices than fuses Some examples oof such thigns are resettable fuses built using bi-metallic technology and PTC-polymer devices are used in some electronics devices to guard against overcurrent damage Thise devices act like automatically resetting fuses

A device called Miniature Circuit Breaker is is used to replace fuses in electrical distribution systems (mains electrical panel) Miniature circuit Breaker can be is used in lighting distribution system or motor distribution system for protecting overload and short-circuit in the system Miniature circuit breaker has a switch on it so it cam be used for overload and short-circuit protection as well as for unfrequent on-and-off switching electric equipment and lighting circuit in normal case

Electronics Basics

The Residual Current Device(RCD) is a special electronicelectromechanical protection device that cuts off the fault circuit immediately on the occasion of shock hazard or earth leakage of trunk line Earth Leakage Circuit Breaker (ELCB) is mainly prevent eletric fire and personal casualty accident caused by personal electric shock or leakage of electrified wire netting Residual Current Circuit Breakers (RCCB) is similar to Earth Leakage Circuit Breaker (ELCB) In mains wiring earth leakage circuit breaker is used for the protectionagainst electrical leakage in the circuit of 50Hz or 60Hz When somebody gets an electric shock or the residual current of the circuit exceeds the fixed value the ELCBRCCB can cut off the power

Fuseology Circuit Protection Techologies - Two page magazine column on the correct use of fuses Self-resetting PTC-polymer devices guard against overcurrent damage - tiny positive-temperature-

coefficient resistors made of conductive polymers can often provide cost-effective protection against overcurrents

The fuse-selection checklist a quick update - a fuse-selection checklist now must include the I2t parameter

Batteries 10 things to know about batteries - mostly about video camera batteries Battery Backup Applications Handbook NiCd battery FAQ Proper handling helps make the most of Li-ion batteries - Li-ion batteries pack the most power per unit

volume but excessive charging or discharging can damage or destroy the battery and its surroundings carefully designed circuits help you avoid such dire outcomes

Sizing Up The Benefits Of Integrated Battery Electronics Smart-battery technology power managements missing link - you no longer need to view a battery as a

power-generating element whose characteristics are beyond your knowledge and controla PSpice models nickel-metal-hydride cells - nickel-metal-hydride (NiMH) battery model accurately predicts

the discharge characteristics of an NiMH cell (or groups of cells) Testing batteries The more things change the more they stay the same - Despite new chemistries

improved manufacturing methods smart-battery technologies and a host of Information Age uses batteries for consumer applications continue to rely heavily on functional testing for characterization and evaluation

The Video Battery Handbook - guide to the care and feeding of video batteries Varta Battery Know-how

Lamps Applications of neon glow lamps - This page contains some applications of neon glow lamps which are

very common components that can do more than simply produce a weak light Comprehensive Fluorescent Tube Data Lamp information - brand names and most common types are listed for three major lamp producers Simple applications of neon glow lamps The main voltage monitor - simply a lamp that glows when the

main voltage is present

Misc Peltier coolersheaters SAW filters and resonators provide cheap and effective frequency control Testing MEMS Dont reinvent the wheel - but take little on faith - MEMS which not only condition signals

but also move require consummate care in handling But the manufacturers have figured out much of

Electronics Basics

what you must know to successfully apply the devices So be highly selective in choosing where to independently build up your private body of knowledge

Tomi Engdahls list of basic electronics components

Related Pages Basic Components List Chip datasheet search engines

httpwwwepanoramanet ltmailtowebmasterepanoramanetsubject=Feedback on basicshtml pagegt

Back to electronics home page

[ webmaster ] [ feedback ] [ friend ][ main index ] [ Disclaimer ] [ Legal Notice ]

Local Disk

Electronics Basics

Few designers spend time pondering the traits of resistors capacitors or other simple passive components Determine the necessary nominal value tolerance and temperature coefficient for each instance in your circuit and youre pretty much done Consider the nonelectrical variables like package and pricing and youre a certifiable good corporate citizen

When it comes to the active components there are also many other things to consider

Component Handling Precautions - one should take reasonable care in handling all components especially nowadays when so many are of small size but certain components can be damaged by high voltage static charges

Electronic component v-i curve photos - transistors FETs photocell transformer capacitor How to read a semiconductor data sheet - Never design with typical specifications unless you are in the

habit of designing with meaningless data The front page of a data sheet for semiconductors and most other products contains the wishes and hopes of marketing Sadly wishes and hopes are not design parameters So the front page of a data sheet contains no useful information unless the marketers run out of lies

Resistor colour codes and capacitor values

Component markings explained A rudimentary resistor identifier - Select colors matching those of the resistor and get the value of the

resistor needs a browser which supports JavaScript Capacitor color codes - in Finnish Resistor color codes - text only version also available in Finnish Resistor Color Codes Semiconductor Classification - Semiconductor devices are classified by the manufacturer using a unique

part numbering system Semiconductor markings explained - what European and Japanise semicondictor component codes mean

also available in Finnish Surface Mount (SMD) TransistorsDiode FAQ The SMD Codebook - To identify a particular SMD device first identify the package style and note the ID

code printed on the device Now look up the code in the alphanumeric listing Transistor Info - transistor markings described Transistor marking codes

ResistorsResistors are electronic components used extensively on the circuit boards of electronic equipment Resistors are usually used to limit current attenuate signals dissipate power (heating) or to terminate signal lines Resistors are usually color coded with stripes to reveal their resistance value (in ohms) as well as their manufacturing tolerance

Most importans characteristics of resistor are the resistance tolerance of resistance and the power handling capacity Resistors are generally available from the fractions of ohms up to several megaohms (higher value special components are also available) Most small general purpose resistors have power handling capacity of around 025W Most resistors used to be this type and most electronics designs expect this kind of resistor unless the power rating is mentiones In typical circuits you can nowadays see resistors with power handling of 0125W up 1W Also special power resistors are available generally with power rating from few watt up to 50-100W Higherst power power resistors are generally built to metal case which is designed to be connected to a heatsink

Electronics Basics

General

Power supply ICs

Standard logic ICs

Electronics Basics

Other amplifier ICs

Comparators

Other analogue ICs

Electronics Basics

Voltage references

Electronics Basics

General

Electronics Basics

Capacitor markings

Electronics Basics

General

Electronics Basics

Toroid coil winding

Electronics Basics

General

Electronics Basics

Transformer design

Electronics Basics

Audio transformers

Electronics Basics

RF transformers

Electronics Basics

Pulse transformers

Electronics Basics

transformers

Electronics Basics

220 = 220 degC 250 = 250 degC

General

Electronics Basics

Internaltionally

linear power supply

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

General

Power supply ICs

Standard logic ICs

Electronics Basics

Other amplifier ICs

Comparators

Other analogue ICs

Electronics Basics

Voltage references

Electronics Basics

General

Electronics Basics

Capacitor markings

Electronics Basics

General

Electronics Basics

Toroid coil winding

Electronics Basics

General

Electronics Basics

Transformer design

Electronics Basics

Audio transformers

Electronics Basics

RF transformers

Electronics Basics

Pulse transformers

Electronics Basics

transformers

Electronics Basics

220 = 220 degC 250 = 250 degC

General

Electronics Basics

Internaltionally

linear power supply

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

General

Power supply ICs

Standard logic ICs

Electronics Basics

Other amplifier ICs

Comparators

Other analogue ICs

Electronics Basics

Voltage references

Electronics Basics

General

Electronics Basics

Capacitor markings

Electronics Basics

General

Electronics Basics

Toroid coil winding

Electronics Basics

General

Electronics Basics

Transformer design

Electronics Basics

Audio transformers

Electronics Basics

RF transformers

Electronics Basics

Pulse transformers

Electronics Basics

transformers

Electronics Basics

220 = 220 degC 250 = 250 degC

General

Electronics Basics

Internaltionally

linear power supply

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

Other amplifier ICs

Comparators

Other analogue ICs

Electronics Basics

Voltage references

Electronics Basics

General

Electronics Basics

Capacitor markings

Electronics Basics

General

Electronics Basics

Toroid coil winding

Electronics Basics

General

Electronics Basics

Transformer design

Electronics Basics

Audio transformers

Electronics Basics

RF transformers

Electronics Basics

Pulse transformers

Electronics Basics

transformers

Electronics Basics

220 = 220 degC 250 = 250 degC

General

Electronics Basics

Internaltionally

linear power supply

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

Other amplifier ICs

Comparators

Other analogue ICs

Electronics Basics

Voltage references

Electronics Basics

General

Electronics Basics

Capacitor markings

Electronics Basics

General

Electronics Basics

Toroid coil winding

Electronics Basics

General

Electronics Basics

Transformer design

Electronics Basics

Audio transformers

Electronics Basics

RF transformers

Electronics Basics

Pulse transformers

Electronics Basics

transformers

Electronics Basics

220 = 220 degC 250 = 250 degC

General

Electronics Basics

Internaltionally

linear power supply

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

Other amplifier ICs

Comparators

Other analogue ICs

Electronics Basics

Voltage references

Electronics Basics

General

Electronics Basics

Capacitor markings

Electronics Basics

General

Electronics Basics

Toroid coil winding

Electronics Basics

General

Electronics Basics

Transformer design

Electronics Basics

Audio transformers

Electronics Basics

RF transformers

Electronics Basics

Pulse transformers

Electronics Basics

transformers

Electronics Basics

220 = 220 degC 250 = 250 degC

General

Electronics Basics

Internaltionally

linear power supply

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

Voltage references

Electronics Basics

General

Electronics Basics

Capacitor markings

Electronics Basics

General

Electronics Basics

Toroid coil winding

Electronics Basics

General

Electronics Basics

Transformer design

Electronics Basics

Audio transformers

Electronics Basics

RF transformers

Electronics Basics

Pulse transformers

Electronics Basics

transformers

Electronics Basics

220 = 220 degC 250 = 250 degC

General

Electronics Basics

Internaltionally

linear power supply

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

General

Electronics Basics

Capacitor markings

Electronics Basics

General

Electronics Basics

Toroid coil winding

Electronics Basics

General

Electronics Basics

Transformer design

Electronics Basics

Audio transformers

Electronics Basics

RF transformers

Electronics Basics

Pulse transformers

Electronics Basics

transformers

Electronics Basics

220 = 220 degC 250 = 250 degC

General

Electronics Basics

Internaltionally

linear power supply

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

General

Electronics Basics

Capacitor markings

Electronics Basics

General

Electronics Basics

Toroid coil winding

Electronics Basics

General

Electronics Basics

Transformer design

Electronics Basics

Audio transformers

Electronics Basics

RF transformers

Electronics Basics

Pulse transformers

Electronics Basics

transformers

Electronics Basics

220 = 220 degC 250 = 250 degC

General

Electronics Basics

Internaltionally

linear power supply

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

Capacitor markings

Electronics Basics

General

Electronics Basics

Toroid coil winding

Electronics Basics

General

Electronics Basics

Transformer design

Electronics Basics

Audio transformers

Electronics Basics

RF transformers

Electronics Basics

Pulse transformers

Electronics Basics

transformers

Electronics Basics

220 = 220 degC 250 = 250 degC

General

Electronics Basics

Internaltionally

linear power supply

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

Capacitor markings

Electronics Basics

General

Electronics Basics

Toroid coil winding

Electronics Basics

General

Electronics Basics

Transformer design

Electronics Basics

Audio transformers

Electronics Basics

RF transformers

Electronics Basics

Pulse transformers

Electronics Basics

transformers

Electronics Basics

220 = 220 degC 250 = 250 degC

General

Electronics Basics

Internaltionally

linear power supply

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

General

Electronics Basics

Toroid coil winding

Electronics Basics

General

Electronics Basics

Transformer design

Electronics Basics

Audio transformers

Electronics Basics

RF transformers

Electronics Basics

Pulse transformers

Electronics Basics

transformers

Electronics Basics

220 = 220 degC 250 = 250 degC

General

Electronics Basics

Internaltionally

linear power supply

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

Toroid coil winding

Electronics Basics

General

Electronics Basics

Transformer design

Electronics Basics

Audio transformers

Electronics Basics

RF transformers

Electronics Basics

Pulse transformers

Electronics Basics

transformers

Electronics Basics

220 = 220 degC 250 = 250 degC

General

Electronics Basics

Internaltionally

linear power supply

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

General

Electronics Basics

Transformer design

Electronics Basics

Audio transformers

Electronics Basics

RF transformers

Electronics Basics

Pulse transformers

Electronics Basics

transformers

Electronics Basics

220 = 220 degC 250 = 250 degC

General

Electronics Basics

Internaltionally

linear power supply

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

Transformer design

Electronics Basics

Audio transformers

Electronics Basics

RF transformers

Electronics Basics

Pulse transformers

Electronics Basics

transformers

Electronics Basics

220 = 220 degC 250 = 250 degC

General

Electronics Basics

Internaltionally

linear power supply

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

Audio transformers

Electronics Basics

RF transformers

Electronics Basics

Pulse transformers

Electronics Basics

transformers

Electronics Basics

220 = 220 degC 250 = 250 degC

General

Electronics Basics

Internaltionally

linear power supply

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

RF transformers

Electronics Basics

Pulse transformers

Electronics Basics

transformers

Electronics Basics

220 = 220 degC 250 = 250 degC

General

Electronics Basics

Internaltionally

linear power supply

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

RF transformers

Electronics Basics

Pulse transformers

Electronics Basics

transformers

Electronics Basics

220 = 220 degC 250 = 250 degC

General

Electronics Basics

Internaltionally

linear power supply

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

Pulse transformers

Electronics Basics

transformers

Electronics Basics

220 = 220 degC 250 = 250 degC

General

Electronics Basics

Internaltionally

linear power supply

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

transformers

Electronics Basics

220 = 220 degC 250 = 250 degC

General

Electronics Basics

Internaltionally

linear power supply

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

220 = 220 degC 250 = 250 degC

General

Electronics Basics

Internaltionally

linear power supply

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

220 = 220 degC 250 = 250 degC

General

Electronics Basics

Internaltionally

linear power supply

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

Internaltionally

linear power supply

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

Relay information

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

Relay circuits

Switches

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

a button

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

UJT or thyristor

Electronics Basics

Local Disk

Electronics Basics

Local Disk

Electronics Basics

Local Disk

Electronics Basics

Local Disk

Electronics Basics

Local Disk

Electronics Basics

Documents

Electronics Basics Transformers