45568141 Elecs Refresher

7/29/2019 45568141 Elecs Refresher

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ELECTRICITY & MAGNETISMCoulombs Law law that describes the force of attraction orrepulsion between two charges is directly proportional to theirstrengths and inversely proportional to the square of the distancebetween them. The basic law for interaction of charged bodies atrest.Coulombs first law of electrostatics law that describes theforce of attraction or repulsion between two magnetic poles isdirectly proportional to their strengths.Coulombs second law of electrostatics law that describesthe force of attraction or repulsion between poles is inverselyproportional to the square of the distance between them.Gausss Law The summation of the normal component of the

electric field displacement E over any closed surface is directlyproportional to the electric charge within the surface.Faradays Law States that the magnitude of the emf induced ina circuit is proportional to the rate of change of the magnetic fluxthat cuts across it.Faradays first Law Electromotiveforce (emf) is inducedwhenever a conductor cuts magnetic flux.Faradays second Law The magnitude of electromotiveforce(emf) s induced when a conductor cuts magnetic flux is directlyproportional to its rate.Faradays Law In Electromagnetism, the law that determinesthe amount of induced voltage.Lenz Law In Electromagnetism, the law that determines thepolarity of an induced voltageLenz Law In all cases of electromagnetic induction, the currentsetup by an induced voltage tends to create flux whose direction

opposes any change in the existing flux.Lenzs Law In electronics, an induced current will be in such adirection that its own magnetic field will oppose the magnetic fieldsthat produce the same.Curies Law States that the magnetic susceptibilities of mostparamagnetic substance are inversely proportional to theirabsolute temperature.Curie-Weiss Law relating between the magnetic and electricsusceptibilities and the absolute temperatures which is followed byferromagnets, antiferromagnets, non-polar ferroelectrics,paramagnts.Childs Law States that the current in a thermionic diode variesdirectly with the three-halves power of anode voltage and inverselywith the square of the distance between the electrodes.Wiedemann-Franz Law - States that the ratio of the thermalconductivity to the electric conductivity is proportional to theabsolute temperature for metal

Amperes circuital Law A law establishing the fact that thealgebraic sum of rises and drops of the mmf around a closed loopof a magnetic circuit is 0.Law of conservation of energy The net electric charge in anisolated system remains constantWiegand effect The effect that describes the ability of amechanically stressed ferromagnetic wire to recognize rapidswitching of magnetization when subjected to a DC magnetic field.Hall effectsmall voltage is generated by a conductor withcurrent in an external magnetic field. Used in the gaussmeter tomeasure flux density.Edison effect The emission of electrons from hot bodiesWall effect ionization by electrons liberated from the wallsBridgman effect phenomenon that when an electric currentpasses through an arisotropic crystal, there is an absorption orliberation of heat.

Webers Theory of Magnetism Assumes that all magneticsubstance is composed of tiny molecular magnets.Domain Theory theory based on the electron spin theory; If anatom has an equal number of electrons spinning in oppositedirections, the magnetic field surrounding the electron cancel oneanother, the atom is unmagnetized.Ewings Theory of ferromagnetism assumes each atom is apermanent magnet which can turn freely about its center under theinfluence of applied fields and other magnetsExclusion Principle States that each electron in an atom musthave a different set of quantum numbers.Pauli exclusion principle states that only two electrons withdifferent spins are allowed to exist in a given orbitHans Christian Oersted relationship between magnetism andelectricityMichael Faraday theory of electromagnetic induction, 1891

James Clerk Maxwell electromagnetic theory of light, 1862Andre Ampere current carrying conductor can attract & repellike magnetKamerlingh Onnes Superconductivity, 1911Self induced emfdue to the change of its own flux linked with Mutually induced emf to the changing current of anotherneighboring coilStatically induced emf conductor is stationary, magnetic fieldis movingUnit pole pole which when placed in air from a similar and equpole repels it with force of 1/4piu newtonsMagnetic pole the intensity of magnetic lines of force ismaximum.

North pole pole where magnetic lines of force are originatingDiamagnetic permeability slightly less than that of free spaceParamagnetic permeability slightly greater than that of freespaceFerromagnetic have very high permeabilitiesConductor valence electron less than 4Semiconductor valence electron equal to 4Insulator valence electron greater than 4Metallic bond bonding of atoms that is due to the force ofattraction between positive ions and a group of negative ions.Ionic bond formed when one or more electrons in the outermosenergy orbit of an atom are transferred to another.Covalent bond formed when electrons in the outermost energyorbits of the atoms are shared between two or more electronsVan der Waals bond formed when there exist distantelectronic interactions between charges present in the neighborin

atomsPermalloy iron 22%, nickel 78%Hipernik iron 40%, nickel 60%

Alnico aluminum, nickel, iron, cobalt, copper, titanium at 12gradesManganin 84% copper, 12% manganese and 4% nickelVector quantity Magnetic field intensity, field, magneticintensity, electric flux density, electric field intensityScalar quantity Electric potential, electric fluxInsulator widest gap between valence band and the conductionbandConductor smallest gap between valence band and theconduction bandBand gap difference in energy between the valence andconduction bandCrystalline solids in which the position of atoms arepredetermined

Amorphous/Non-crystalline has no defined crystal structureMica used as the insulating material or dielectric in an electricionGlass has the highest dielectric strengthPorcelain used as the dielectric material in high voltagetransformersQuantum definite discrete amount of energy required to movean electron from a lower shell to a higher shell.

Amber means elektron in GreekValence band series of energy levels containing the valenceelectronPlasma gases with charged particleElectric dipole a combination of two charges, with equal chargmagnitude but opposite signsKeeper used to maintain strength of magnetic fieldToroid an electromagnet with its core in the form of a close

magnetic ringdomain - A group of magnetically aligned atomsthermonic emission - Evaporation of electron from a heatedsurfaceBack emf- refers to the voltage opposing the applied emfMadelung constant factor used to correct for the electrostaticforcesMagnetic material loss its ferromagnetic properties at a point callCurie temperatureThe dielectric constant of most materials lies between 1 and 101.15 to 1.25 is the usual value of leakage coefficient for electricamachinesCurrent carriers in conductors are valence electronsDielectric is another name for insulatorRF current flow along the surface.


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Because ofskin effectresistance is different for RF current thenDCSteelis hard to magnetize because of its low permeabilityOne of the common application of an air-cored choked is at RadiofrequencyOhms law can be used only to a linear circuit or componentMagnetic field around the conductor is determined by the amountof currentIn electro-mechanical conversion device, the reason why a small airgap is left between the rotor and stator is to permit mechanicalclearance.Permanent magnets can be found in earphonesTemporarymagnets are commonly employed in motors

Hardenedsteelis used bypermanentmagnets as the magneticmaterialSoftiron is used by temporarymagnets as the magneticmaterialSilicon steel materials has the leasthysteresis looparea

Magnetomotiveforce (mmf)

Ampere-Turn

AT

GilbertGb

1 AT =1.257 Gb

Magnetic FieldStrength

Ampere permeter A/m

OerstedOe (Gb/cm)

1 A/m =0.01257 Oe

Magnetic Flux Weber Wb Maxwell Mx 1 Wb =10^8 Mx

Magnetic Fluxdensity

TeslaT (Wb/m^2)

GaussG

(Mx/cm^2)

1T = 10^4G

V Volt Emf Mmf Amp-turn

I Amp Current Magnetic flux WeberR Ohm Resistance Reluctance 1/H

V/m Field strength Magnetization

Amp/m H

J A/m Currentdensity

Flux density Tesla B

Ohm-m Resistivity Reluctivity m/H VG Siemen

sConductance Permeance Henry P

S/m Conductivity Permeability H/m


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ELECTRICAL CIRCUITSKirchhoffs first law The sum of all currents entering a junctionis equal to the sum of currents leaving away from that junction.Kirchhoffs second law In a mesh, the algebraic sum of allvoltages and voltages drops is equal to zero.CR Law a law which states that when a constant electromotiveforce is applied to a circuit consisting of a resistor and capacitorconnected in series, the time taken for the potential on the platesof the capacitor to rise to any given fraction of its final valuedepends only on the product of capacitance and resistance.Thevenins theorem Used to simplify complex circuits wherein,the simplified circuit contains an equivalent open circuit resistanceand open circuit voltage.

Nortons theorem reverse of Thevenins theoremIn Nortons theorem, the short circuit current is obtained byshortening the load terminalsSuperposition theorem Used in solving electrical circuits withseveral voltage sources.Superposition theorem Used in simplifying circuit analysis byconsidering the effect of supply voltages one at a time.The superposition theorem is used when the circuit contains anumber of voltage sources.Compensation theorem Any resistance R in a branch of anetwork in which a current I is flowing can be replaced by a voltageequal to IR.Reciprocity theorem If an emf in circuit A produces a current incircuit B, then the same emf in circuit B produces the same currentin circuit A.Edge effect refers to the outward-curving distortion of the lines

of force near the edges of two parallel metal plates that form acapacitor.Mesh A chosen closed path of current flow in a network.Loop A set of circuit elements that forms a closed path in anetwork over which signal can circulateNode a reference point chosen such that more branches in acircuit met

Junction A common connection between circuit elements orconductors from different branches.Ground return point in a circuit, where all voltage measured arereferred.KVL Mesh analysisKCL Nodal analysisTrue power the power dissipated across the resistance in an ACcircuit.A series circuit at resonance would mean, the circuit is resistiveA parallel circuit at resonance would mean, the circuit is resistiveIn ac-circuit, if the voltage and current are in phase, the circuit isresistive.If the current and voltage has a phase difference, the circuit isreactive.

If the current in ac-circuit leads the voltage by 90, the circuit iscapacitive.

If the current in ac-circuit lags the voltage by 90, the circuit isinductive.In a series ac-circuit, if the line frequency is more than theresonant frequency, the circuit behaves as inductive.If the line frequency of a parallel ac-circuit is less than the resonantfrequency, the circuit behaves as reactive.If an ac-series circuit is supplied with a source whose frequency isless than that of fr, the circuit becomes capacitive.Smaller resistors usually have high resistance value.When the temperature of a copper wire is increased, its

resistance is increased.The resistance of an insulator decreases when itstemperature is increased.Skin effectincreases the resistance of wire at high frequenciesThe result ofrustin electrical wire connection is resistanceWattage rating of a resistor determines its ability to absorbheat.Resistors with high value usually have lower wattage ratingbecause oflower currentHigh resistance values are a consequence of the thinness ofthe film.A disadvantage of a wire-wound resistoris that it hasreactance in radio-frequencycircuits.Bifilar resistor a resistor wound with a wire doubled back onitself to reduce the inductance.A rheostatis a form of variable resistor.

Airdielectric is generally employed by a variable capacitor.Barium-strontium titanite dielectric material is also calledceramicPaperhas the lowest dielectric strengthBarium-strontium titanitedielectric makes the highest-capacitance capacitor.Electrolytic capacitors are used only in dc circuits.Electrolytic capacitor has the highest cost per microfarad.Electrolytic capacitor is suitable for dc filter circuits.A capacitorconsists ofconductors separated by a dielectricThe capacitance of a capacitor is directly proportional to relativepermittivity.In a multiplate capacitor, the plate area is increased.

For mutli-plate capacitor, capacitance is proportional to number oplates less one (n-1).A capacitoris used to block dc currentThe charging of a capacitorthrough a resistance obeysexponential law.It is impossible to change the voltage across a capacitor instantlyas this would produce infinite current.Leakage resistance in a capacitor results into internal heatingA capacitor opposes change in voltage.Capacitance increases with larger plate area and lessdistance between platesIncreasing capacitance is considered the effect of a dielectricmaterial.A gang capacitoris a variable capacitor in which capacitance isvaried by changing the plate areaA trimmeris a variable capacitor in which capacitance is varied b

changing the distance between platesStray capacitance exist not through design but simply becausetwo conducting surface are relatively close to each other.The ratio between the active powerand the apparent powerothe load in an ac circuit is calledpower factor.An inductive loadalways has a lagging power factor.The power factor of a series LC circuitis 0.The rms value of a triangular or sawtooth waveform is 0.577times its peak value.The average value of triangular or sawtooth wave is 0.500 timeits peak value.1.73 is the peak factor of a triangular wavePeak factor for alternating current or voltage varying sinusoidally1.4142The factor 0.707 for converting peak to rms applies only to sinewaves.For a linear, rms voltage or current is used to calculate averagepower.The current is 0.707 times the maximum current at half-powerpoints of a resonance curve.Zero reading on an ohmmeter for a shorted capacitorAn open resistor when checked with an ohmmeter reads infinite.Surge voltage is the maximum voltage that can be applied acrothe capacitor for very short period of time.Breakdown voltage refers to the lowest voltage across anyinsulator that can cause current flow.The ratio of the flux density to the electric field intensity in thedielectric is calledpermittivity.The ratio of maximum value to the effective value of an alternatinquantity is calledpeak factor.The graph between an alternating quantity and time is calledwaveform.Reactance chartcan be used to estimate resonant frequency an

to find reactance at any frequency for any value of capacitor orinductor.Temperature coefficient of resistance A factor that stateshow much the resistance changes for a change in temperature.The ohmic value of a resistor with negative temperaturecoefficientincreases with decreasing temperature.Carbon has a negative temperature coefficient.Manganin has apositive temperature coefficientTungsten filament of bulbs has a hot resistance higher than itscold resistance due to its temperature coefficient which is

positive.The temperature coefficient of resistance ofelectrolytes isnegative.

In apure capacitance, current lead voltage by 90

In an RL series circuit, current lags voltage by less than 90In a rectangular wave, form factor is 1.0


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In a triangular wave, form factor is 1.16For a series AC circuit, voltage is not usedas a referencephasor.For aparallel AC circuit, voltage is usedas a reference phasor.The Q-factor of a series resonant circuitis also known as voltagemagnification factor.The Q-factor of aparallel resonant circuitis also known as currentmagnification factor.Parallel resonantcircuit is sometimes called rejector circuit.Series resonantcircuit is sometimes known as acceptor circuit.In dividing or multiplying phasorquantities,polar form isused.In adding or subtracting phasorquantities, rectangular form

is used.Conventional flow assumes charges flow frompositive tonegative.Electron flow assumes charges flow from negative to positive.The symbol Q refers to quality factor.The reciprocalof quality factor is dissipation factor.Nortons theorem usually used in the analysis oftransistorcircuitThevenins theorem generally used in the analysis ofvacuumtubesNortons theorem is a form ofcurrent equivalent circuitThevenins theorem is a form ofvoltage equivalent circuitParallel resonantcircuit is also known as anti-resonantcircuitThe curve between current and frequency is termed as resonancecurve.Atparallel resonance, the current flowing through L and C are

equal.Voltage resonance means series resonanceThe resonance curve is a plot of frequency versus current for aseries RLC circuit.Series resonantcircuit is inductive if it operates at a frequencyhigher than the resonant frequency.When two complexconjugates are subtracted, the result is aquadrature componentonly.Iftwo complex conjugates are added, in-phase componentresults

Alloyis a fusion of elements, without chemical action betweenthem.

Anticapacitance switch a switch designed to have lowcapacitance between its terminal when open.Phasoris a rotating vector whose projection can represent eithercurrent or voltage in an ac circuitCryogenic conductor another term for superconductorFaradic current An intermittent and non-symmetricalalternating current like that obtained from the secondary windingof an induction coil.

Joules the term used to express the amount of electrical energystored in electrostatic field.Phasor quantity refers specifically to steady state values ofquantities in ac circuits which are complex numbers.Non-linear circuit a circuit whose parameters change withvoltage or currentLiquids that are good conductors because of ionization are calledelectrolytes.Manganin is a common material used in wire-wound resistors.Elastance is the reciprocal of capacitance.Permeabilityis otherwise known as magnetic conductivity.Effective value is considered as the most important value of asine wave.

Tank circuitis a parallel LC circuit.When current and voltage are in phase in an ac circuit, thereactance is equal to zero.The voltage cannot be exactly in phase with the current in a circuitthat contains only capacitance.An open inductorhas infinite resistance andzero inductance.The reciprocal of a complex number is a complex numberMetal tin becomes superconductor at approximately 3.7 K.A real current source has a large internal resistance.The reason why alternating current can induce voltage is it has avarying magnetic field.In an ac-circuit, the power dissipated as heat depends onresistance.The maximum power transfer theorem is used in electronic circuitsAccording to Gauss theorem, fluxcan be equated to charge.

The phase of an alternating quantity is defined as the fractionalpart of a period or cycle through which the quantity has advancedfrom selected origin.The admittance of aparallel RLC circuit is found to be the phasosum ofconductance and susceptance.In an inductive coil, the rate of rise of current is maximum nearthe final maximum value of current.For a series circuit, the higher the quantity factorthe narrowthe passband.The impedance in the study of electronics is represented byresistance and reactance.An ideal current source has an internal conductance ofzerosiemen/s.

Nortons theorem is the converse of Thevenins theoremELECTRONIC DEVICESIntrinsic the name of the semiconductor material that has anequal number of electrons and holesElement that has four valence electrons are classified aselemental semiconductorGermanium (Ge) example of elemental semiconductorGallium Arsenide (GaAs), Gallium Phosphide (GaP),

Aluminum Arsenide (AlAs) example of a compoundsemiconductorCovelent bond the chemical bond that is present in a crystallattice of silicon atomsForbidden gap the area that separates the valence band andthe conduction band.At absolute zero temperature, semiconductor acts as an insulatoThe electron flow in a semiconductor material is opposite in

direction of hole flow10 - 10^4 ohm-cm typical range of the resistivity of asemiconductorMetallic bonding chemical bond that is significant in metalsIntrinsic semiconductor a semiconductor that is free fromimpuritiesDoping the process of adding impurities in a semiconductorPentavalent impurities with five valence electronsTrivalent impurities Example of acceptor impuritiesIf the substance used in doping has less than four valenceelectrons, it is known as acceptor

Antimony(Sb), Arsenic(As), Phosphorus(P) commonly usedas donor impuritiesBoron(B), Gallium(Ga), Indium(In) Example of trivalentimpuritiesDonor-doped semiconductor becomes an N-type semiconductoCompensated semiconductor a semiconductor that is dopedwith both donor and acceptor impuritiesThe resistance of a semiconductor is known as bulk resistanceSilicon the most extensively used semiconductorIntrinsic semiconductor semiconductor whose electron andhole concentrations are equalSilicon is widely used over germanium due to its low leakagecurrentDrift current current flow in a semiconductor that is due to theapplied electric fieldDiffusion current the movement of charge carriers in asemiconductor even without the application of electric potentialTypically, 0.05 eVenergy is required for a valence electron tomove to the conduction band for a doped semiconductorConduction of electrons in a doped semiconductor happens atconduction bandValence band where the conduction of holes occur in a doped

semiconductorIn energy band diagram of a doped semiconductor, the donor leveis near the conduction bandThe acceptor level in a doped semiconductor is near the valencband levelIn a semiconductor material, the number of free electronsincreases when the temperature risesThe electrical resistance of a semiconductor material willdecrease as the temperature increasesIonization potential the potential required to remove a valencelectronSilicon nonmetalGermanium a semiconductor that is classified as a metalloid orsemimetalGermanium semiconductor that is very rare, it only occurs inminute quantities in many metal sulfides


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Compound semiconductors are also known as inter-metallicsemiconductorsCompound semiconductor semiconductor that is mostly usedin devices requiring the emission or absorption of lightsFor high-speed integrated circuit, Gallium arsenidesemiconductor material is best to be usedOne part per million impurity concentration is needed for asample of silicon to change its electrical property from a poorconductor to a good conductorThe restriction of certain discrete energy levels in a semiconductormaterial can be predicted generally by using Bohr modelElectron Volt (eV) is defined as the energy acquired by anelectron moving through a potential of one volt.

EHP optical generation is the basis in operation ofsemiconductor photoconductorsSelenium the semiconductor that is used in xerographyRecombination - when an electron at the conduction band fallsback to the valence band it will recombine with the hole.Germanium semiconductor is mostly used to detect near infrared.Silicon carbide (SiC) semiconductor is good for high-temperatureapplicationsIndium antimonide semiconductor has the highest mobilityA semiconducting glass is known as amorphous semiconductorFor an electroluminescent of green and red lights, gallium

phosphide semiconductor is bestLess than 1 watt typical range of power dissipation for asemiconductor to be considered as low power or small signal

Zinc Sulfide (ZnS) semiconductor material has the highestenergy gap

InSb semiconductor has the smallest energy gap

Mobility defined as the average drift velocity of electrons andholes per unit electrostatic field. The ease with which a chargecarrier moves in a semiconductor material

InSb semiconductor material has the highest value of electron-mobility

AIP semiconductor material has the slowest electron-mobilityPn junction is formed when n-type and p-type semiconductors arebrought togetherPN junction acts as a one way valve for electrons because whenelectrons are pump from P to N, free electrons and holesare force apart leaving no way for electrons to cross the

junctionJunction diode the device that is formed when an n-type and p-type semiconductors are brought togetherForward bias an external voltage applied to a junction reducesits barrier and aid current to flow through the junctionDiode a device containing an anode and a cathode or a pnjunction of a semiconductor as the principal elements and providesunidirectional conductionUnidirectional conduction in two-electrodes in any device otherthan a diode, such that rectification between the grid and cathodeof a triode, or asymmetrical conduction between the collector andbase of a transistor is called diode actionThe p-type material in a semiconductor junction diode is technicallytermed as anodeCathode in a semiconductor junction diode is referred to the n-type terminalDepletion region the area in the semiconductor diode wherethere are no charge carriersA junction diode is said to be forward-biased ifa voltage greater

than threshold is applied, with cathode less positive thananodeReverse saturation currentis a very small amount of currentthat will flow in the diode when it is reverse biasedThreshold voltage the minimum voltage required before adiode can totally conduct in a forward directionThe threshold voltage of the diode will decrease when it operatesat higher temperaturesThe forward current in a conducting diode will increase as theoperating temperature increases.As the operating temperature of a reverse-biased diode isincreased, its leakage or reverse saturation current will increaseexponentiallyReverse current the small value of direct current that flowswhen a semiconductor device has reverse bias

The breakdown voltage of a junction diode will decrease asoperating temperature rises.

In every increase of 10 C in the operating temperature of a diodewill cause its reverse saturation current to doubleDc resistance the resistance of the diode when operating at asteady state voltageDynamic resistance the resistance of the diode that issignificant when operating with a small ac signalWhen a diode is used in large ac voltages, the resistance that is tobe considered is average resistanceThe diode resistance will decrease when the applied voltage isincreasedThe primary use of Zener diode in electronic circuits is a voltage

regulatorIn electronics, an avalanche breakdown primarily depends onionizationWhen a diode is reverse biased the depletion region widens, sinceit is in between positively charge holes and negatively chargeelectrons, it will have an effect of a capacitor, this capacitance iscalled transition capacitanceIn a semiconductor diode, the total capacitance, that is thecapacitance between terminals and electrodes, and the internalvoltage variable capacitance of the junction is called diodecapacitanceDiffusion capacitance or storage capacitance is significantwhen the diode is forward biasedVaractor and varistor a diode that is especially designed tooperate as a voltage-variable capacitor. It utilizes the junctioncapacitance of a semiconductor diode

The capacitance of a varactor will increase when the forward biavoltage is increased.Reverse recovery time the time taken by the diode to operatein the reverse condition from forward conductionIn operating a diode at high-speed switching circuits, one of themost important parameters to be considered is reverse recovertime.Forward recovery time the time required for forward voltage current to reach a specified valued after switching the diode fromits reverse-to-forward-biased state.Maximum dissipation power the maximum power the diodecan handleCurrent capacityis the most important specification forsemiconductor diode.The power handling capability of a diode will decrease if it is tooperated at a higher temperaturePower derating factor diode parameter that will inform theuser as to what factor does the power handling capability of thediode is reduced as the operating temperature is increased

Zener diode a semiconductor device especially fabricated toutilize the avalanche or zener breakdown region. This is normallyoperated in the reverse-region and its application is mostly forvoltage reference or regulationTunnel diode Refers to a special type of diode which is capableof both amplification and oscillation

Avalanche the effect when the electric field across asemiconductor is strong enough which causes the free electrons tcollide with valence electrons, thereby releasing more electronsand a cumulative multiplication of charge carriers occur.Tunnel diode a negative resistance diode commonly used inmicrowave oscillators and detectors, it is sometimes used asamplifiers. This device is also known as Esaki diodeGunn diode diode whose negative resistance depends on a

specific form of quantum-mechanical bond structure of the materOne of the electronic semiconductor devices known as diac,function as two terminal bi-directional switchDiac another name of a three-layer diode. This is also considereas an ac diode.Point-contact diode semiconductor diode that have a fine wirewhose point is in permanent contact with the surface of a water osemiconductor material such as silicon, germanium or gallium-arsenideWhen the p-n junction of a semiconductor diode is inserted with aintrinsic material, the diode becomes a PiN diodeShockley diode a four layer semiconductor diode whosecharacteristic at the first quadrant is similar to that of a siliconcontrolled rectifier (SCR)


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Backward diode a diode that is especially processed so that itshigh-current flow takes place when the junction is reverse biased. Itis a variation of a tunnel diode.Thyrector a silicon diode that exhibits a very high resistance inboth direction up to certain voltage, beyond which the unitswitches to a low-resistance conducting state. It can be viewed astwo zener diodes connected back-to-back in series.IMPATT diode a type of Read diode that uses a heavily doped n-type material as its drift regionDiode pack a device containing more than one diode. Anexample is the full-wave bridge-rectifier integrated circuitDiode impedance is the combination of the inductance of theleads and electrodes, capacitance of the junction, and the

resistance of the junction of a semiconductor diodeZener effect In a reverse-biased pn junction, the sudden largeincrease in current that occurs when a particular value of reversedvoltage is reached, and which is due to ionization by the highintensity electric field in the depletion regionGunn effect the appearance of RF current oscillations in a dc-biased slab of n-type gallium arsenide in a 3.3 kV electric field

Zener impedance the impedance presented by a junctionoperating in its zener breakdown region.Characteristic curve a curve showing the relationship betweenthe voltage and the current of the diode at any given temperatureLoad line the line that is plotted in the diode characteristic curvewhich represent the loadThe magnitude of the load-line slope will increase when the loadresistance is decreased.Clipper diode circuit that is used to cut a portion of the input

signalSeries clipper a clipper circuit wherein the diode is connected inseries with the load.Parallel clipper a clipper circuit wherein the diode is shuntedwith the loadClamper a network with a diode an a capacitor that is used toshift the dc-level of the input signalHalf-wave rectifier is a good example ofa series clipperClampermust have a capacitor2 resistors are used in a diode-capacitor half-wave voltage doublerDiode array a combination of several diodes in a single housingDiode chopper a chopper, employing an alternately biaseddiode as the switching element.

Zener voltage regulator a simple voltage-regulator whoseoutput is the constant voltage drop developed across a zener diodeconducting in the reverse breakdown region. The regular circuitconsists of a zener diode in parallel with the load and anappropriate limiting resistorDTL logic circuitry in which diode is the logic element and atransistor acts as an inverting amplifierHalf-bridge bridge rectifier having diodes in two arms andresistors in the other two.Crowbar an over-voltage protection circuit employing a zenerdiode and a SCR whose function is to produce high overload by-pass current on a circuit.The flow of electron in a NPN transistor when used in electroniccircuit is from emitter to collectorTransistor a three terminal, three layer semiconductor devicethat has the ability to multiply charge carriers. This device was firstintroduced at Bell Laboratories, by Brattain and Bardeen in 1947and which opens a completely new direction of interest anddevelopment in the field of electronicsTransistor an active semiconductor device, capable of

amplification, oscillation, and switching action. It is an acronym fortransfer reisistor and had replaced the tube in most applications.The base in the region/area in a transistor is the smallest inconstructionEmitter the region or area in a transistor that is heavily doped

Alloy-diffused transistor a transistor in which the base isdiffused and the emitter is alloyed. The collector is provided by thesemiconductor substrate into which alloying and diffusion areaffected.

Alloy transistor a transistor whose junction are created byalloying

Alloy junction In a semiconductor device, a p-n junction formedby alloying a suitable material such as indium with thesemiconductor.Diffused transistor a transistor in which one or both electrodesare created by diffusion

Bipolar transistor a two-junction transistor whose constructiotakes the form of a pnp or a npn. Such device uses both electronand hole conduction and is current-drivenPoint-contact transistor the predecessor of the junctiontransistor, and is characterized by a current amplification factor,alpha of greater than one.For a transistor, the outer layers are heavily dopedsemiconductorsThe ratio of the total width of the outer layer to that of the centerlayer is 150:1The ratio of the doping level of the outer layers to that of thesandwiched material is 10:1 or lessLimiting the number of free carriers will decrease the

conductivity but increases the resistanceThe term bipolarreflects the fact that holes and electronsparticipate in the injection process into the oppositely polarizedmaterial.Unipolardevice employs only electrons or holeAt forward-biased junction of pnp transistor, majority carriers flowheavily from p- to the n-type materialThe minority-current component of a transistor is called leakagecurrentIco is temperature sensitive, and can severely affect the stabilitof the system, when not carefully examined during designFor the transistor, the arrow in the graphic symbol defines thedirection ofemitter conventional current flow through thedeviceIn the dc mode, the levels of Ic and Ie due to the majority carriersare related by the quantity alpha ()

In the ac mode, alpha is formally called common-base, short-circuit, amplification factorPhrases not pointing in and pointing in simply mean npn and

pnpIn the dc mode, the levels of Ic and Ib are related by a quantity

called

For practical transistor devices, the level of typically rangesmostly in midrange of 50 to 400The formal name of beta is common-emitter forward-currentamplification factor

it is a particularly important parameter that provides a directlink between current levels of the input and output circuits for acommon-emitter configurationThe cutoff region is defined as the area below Ic = IceoWith an ohmmeter, a large or small resistance in either junction oan npn or pnp transistor indicates faulty device

At base-emitter junction, using an ohmmeter, if the positive lead connected to the base and the negative lead to the emitter, a lowresistance reading would indicate npn transistorAt base-emitter junction, if the positive lead is connected to thebase and the negative lead to the emitter, a high resistancereading would indicatepnp transistorHigh-power devices transistors of heavy duty constructionSaturation point on a voltage-current condition curve, the poibelong to which a further increase in voltage produces no furtherincrease in current.Saturation it is applied to any system where levels have reachetheir maximum valuesFor an on transistor, the voltage Vbe should be in theneighborhood of0.7 V

Active region in a transistor amplifier is normally employed forlinear amplifiersIn the active region, the collector-base junction is reverse, while

the base-emitter junction is forward-biasedDc biasing is necessary, in order to establish the proper region ooperation for ac amplificationAt cutoff region, the collector-base and base-emitter junctions of atransistor are both reverse-biasedIn saturation region, the collector-base and base-emitter junctionsof a transistor are both forward-biasedIf the base-emitter junction is reverse biased and the base-collectjunction is forward biased, the transistor will be at cut-off regionTransistor operate at cut-off region if both the base-emitter andbase-collector junctions are reverse-biasedThe transistor should be operating at active region to haveminimum distortion at the output signalQuiescent In dc biasing, it means quiet, still, inactiveEmitter the transistor terminal that handles most current


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Stability factorindicates the degree of change in operating-pointdue to temperature variation in the dc biasingCut-off currentflows between the collector and emitter terminalswhen the base is openWhen the transistor is saturated, Vce is approximately 0 VCollector-emitter resistance of ideal transistor at cut-off is InfiniteIcbo the leakage current that flows at the collector-base junctionwhen the emitter is openReverse saturation current the most correct technical term ofthe reverse leakage current that flows between the collector andbase junctions when the emitter is open circuitIcbo of an ideal transistor is zero mAThe maximum voltage that can be applied across the collector-

emitter terminal for a given transistor is specified as VceoWhen base is common to both the input and output sides of theconfiguration and is usually the terminal closest to, or at groundpotential, it is called common-base terminologyCommon collectortransistor configuration has the highest inputresistanceLower input resistance characteristic refers to that of acommon-base (C-B) as compared to common-emitter (C-E) andcommon-collector (C-C) amplifiersA transistor is said to be configured as common emitter if theemitter terminal is not used as an input nor outputMost frequently used transistor configuration for pnp and npn iscommon-emitterCommon-emitterconfiguration hybrid parameters is usuallyspecified by the manufacturersHr and ho hybrid parameter that is usually neglected in circuit

analysisIn most transistor input equivalent circuit it comprises of a resistorand a voltage sourceCommon-collectorconfiguration has the highest input resistanceCommon-base configuration has a high voltage gain and a currentgain ofapproximately equal to oneCommon-emitterconfiguration has the highest power gainCommon-collectorconfiguration has the highest power gainOutput characteristic curve is most usefulMaximum power curve the graph of the product of collector-emitter voltage Vce and collector current Ic in the transistor outputcharacteristic curveThe base of a transistor serves as a gate element of the FETBJT is current-controlled device; FET is voltage-controlleddeviceAnother difference between a BJT and a FET with regards to itsnormal biasing, is that the input circuit is forward-biased forBJT while reverse for FETDue to the reverse-biased input circuit of FETs, FET offer highinput impedance then BJTThe operation of BJT involves both the flow of electrons and holesand is therefore, considered as a bipolar device. Unlike BJT, FETsoperation involves only either electrons of holes and is consideredas a unipolardeviceConsidered as the basic FET or the simplest form of FET is theJFETS-G-D JFET : E-B-C BJTOne obvious advantage of a JFET over BJT is its high inputresistanceA BJT is a current-controlled current-source device while JFET is avoltage-controlled current source deviceChannel the area in a JFET where current passes as if flows fromsource to drainThe channel of a JFET will skews as current flows to it.

For a normal operation of an n-channel JFET, you bias the gate-source junction by negative-positive respectivelyPinch-off voltage the voltage across the gate-source terminal ofa FET that causes drain current Id equal to zeroDrain-source saturation current the current that flows into thechannel of a JFET when the gate-source voltage is zeroCurrent-voltage characteristic curve the graph of the draincurrent Id versus drain-source voltage Vds with Vgs as theparameterFieldistor an early version of the field effect transistor in whichlimited control of current carriers near the surface of asemiconductor bar or film was obtained by an external electric fieldapplied transversely

JFET A FET in which the gate electrode consists of a pn junctionJFEThas the lowest input resistance

In order to increase further the input resistance of a FET, its gate insulated. An example of this type is the MOS-FETSiO2 is the insulator used in most MOS-FETSubstrate In MOSFET, it is the foundation upon which the devicwill be constructed and is formed from a silicon baseEnhancement type a type of MOSFET wherein originally there no channel between the drain and the sourceDepletion type of MOSFET whose channel is originally thick butnarrows as the proper gate bias is appliedThreshold voltage the amount of voltage needed at the gate-source terminal for an enhancement type MOSFET so that achannel can be formed for the current to flowTo switch off the depletion type MOSFET, the channel should be

depleted. Depletion of the channel is done by applying enoughvoltage across the gate-source terminal. This voltage is calledpinoff voltageThe substrate of a MOSFET is usually connected internally tosourceIn an n-channel enhancement type MOSFET, the gate voltageshould bepositive with respect to the source in order to produceor enhance a channelTo deplete a channel from a p-channel IGFET depletion type, thegate voltage should bepositive with respect to the source.N type material- The substrate used in a p-channel IGFETenhancement typeSubstrate (SS) the base material of a MOSFET which extends aan additional terminalMOSFET enhancement type operates as close as BJT in terms oswitching

Generally, MOSFET has low power handling capability than BJT. Toincrease MOSFET power, the channel should be made wide andshortV-MOSFEThas a wide and short effective channelV-MOSFET a type of FET wherein the channel is formed in thevertical direction rather than horizontalIn general, FETs is particularly more useful in integrated-circuit (IchipsFET a monolithic semiconductor-amplifying device in which ahigh-impedance GATE electrode controls the flow of currentcarriers through a thin bar of semiconductor called the CHANNEL.Ohmic connections made to the ends of the channel constituteSOURCE and DRAIN electrodesSolid State Devices / CircuitsVaractor diodes are commonly used as a voltage controlledcapacitanceThe electrons in the largest orbit travel more slowlythan theelectrons in the smaller orbitsCommon base a transistor configuration with the lowest currengainA semiconductor in its purest form is called intrinsicsemiconductorValence orbit is the other term for outer orbitFor either germanium or silicon diodes, the barrier potentialdecreases 2 mVfor each Celsius degree risePiecewise linear model a diode modeling circuit whichconsiders, the threshold voltage, average resistance and switch athe diodes equivalent circuitDiffusion and drift two mechanisms by which holes andelectrons move through a silicon crystalA semiconductor is an element with a valence offourValence orbitcontrols the electrical properties of the atomConductoris a substance that contains atom with several bands

of electrons but with only one valence electronPure silicon contains 8 valence electrons as a result of covalentbondingThe peak inverse voltage of a full wave center tapped rectifiercircuit is equal to twice the peakof the input signalDiffusion or storage capacitance is the term used to refer to theforward bias capacitance of a diodeThe number of electrons in the valence orbitis considered athe key to electrical conductivityEach atom in a silicon crystal has 8 electrons in its valence orbitLifetime is the amount of time between the creation anddisappearance of a/an free electronA silicon crystal is intrinsic semiconductor if every atom in thecrystal is a silicon atomAt room temperature, a silicon crystal acts approximately like aninsulator


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An extrinsic semiconductor is a doped semiconductorDiffusion is associated with random motion due to thermalagitation in the movement of holes and electrons in a silicon crystalThe peak inverse voltage of a half wave rectifier circuit isapproximately equal to thepeak amplitude of the input signalSilicon that has been doped with a trivalent impurity is called ap-type semiconductorSilicon that has been doped with a pentavalent impurity is called an-type semiconductor

Junction diode is another name for a pn crystalAn acceptor atom is also called trivalent atomPentavalent atom donor atomIn an n-type semiconductor, free electrons are called majority

carriersIn an n-type semiconductor, holes are called minority carriersEach pair of positive and negative ions at the junction is called adipoleWhen temperature increases, barrier potential decreasesAvalanche effects occurs at higher reverse voltagesThe creation of free electrons through zener effect is also known ashigh-field emissionZener effect depends only on the intensity of the electric field

Junction temperature is the temperature inside the diode, rightat the junction of the p and n-type materialsGate voltage is the input parameter of a FETForward current one of the important diode parameter whichgives the magnitude of current the diode can handle withoutburningThe maximum reverse voltage that can be applied before current

surges is called reverse breakdown voltageTunnel diode another name for Esaki diodeThe most important application of Schottky diode is in digitalcomputersA diode is a nonlinear device because its current is not directly

proportional to its voltageThe sum of the resistances of the p-region and the n-region iscalled bulk resistanceThe typical bulk resistance of rectifier diode is less than 1 ohmThe reverse bias diode capacitance is termed as transitionregion capacitanceReverse recovery time the time taken by the diode to operatein the reverse condition from forward conductionApproximately, the atomic weight of germanium is 72.6Atomic weight of silicon at 300K is 28.09An LED and a phototransistor is equivalent to an OptocouplerOptocoupler is otherwise known as OptoisolatorWhen the emitter junction is forward biased while the collectorjunction is reverse biased, the transistor is at active regionWhen both the emitter and collector junction are forward biased,the transistor is said to be at saturation regionSecond approximation An equivalent circuit of a diode in whichit is represented as a switch in series with a barrier potentialThird approximation an equivalent circuit of a diode in which itis represented as a switch with a battery in series with a resistanceA silicon crystal is an intrinsic of semiconductor if every atom inthe crystal is a silicon atomWith npn voltage divider bias, you must use negative powersupplyA half-wave signal has a period of16.7 msA full-wave signal has a period of8.3 msWhen doping increases, bulk resistance of a semiconductordecreases

FEThas the least noise levelMOSFEThas the highest input impedanceThe frequency of a half-wave signal is equal to the linefrequencyFor a full-wave rectifier, the output frequency equals two timesthe input frequencyThe average dc voltage of a half wave rectifier circuit is 31.8% ofthe value of the peak input voltageThe average dc voltage of a full wave rectifier circuit is 63.6% ofthe value of the peak input voltageTypical leakage current in a pn junction is in the order ofAThe resistance of a forward biased pn junction is in the order ofohmThe removal by electronic means of one extremity of an inputwaveform is called clippingShockley diode a type of diode with no depletion layer

Varistor are used for line filtering to eliminate spikes and dips andis also called transient suppressorDiffusion Defined as the random motion of holes and freeelectrons due to thermal agitationThe temperature coefficient of resistance of a semiconductor isnegativeClass A a large signal amplifier which is biased so that collectorcurrent flow continuously during the complete electrical cycle ofthe signal as well as when no signal is presentClass C a large signal amplifier which is biased so that current inon-zero for less than one-half cycleA class AB amplifier stage operates with a small forward bias onthe transistor so that some collector current flow at all times

Derating factor A factor shown on a data sheet that tells howmuch you have to reduce the power rating of a deviceThe time it takes to turn off a forward-biased diode is called thereverse recovery timeA heavily doped semiconductor has low resistanceGallium arsenide, aluminum arsenide and gallium phosphide areclassified as compound semiconductorA lightly doped semiconductor has high resistanceConductance the property or ability of a material to supportcharge flow or electron flowDember effect also known as photodiffusion effectBulk effect an effect that occurs within the entire bulk of asemiconductor material rather than in a localized region or junctioDember effect the creation of a voltage in a conductor orsemiconductor by illumination of one surface.Point-contact diode uses a metal catwhisker as its anode and is

classified as a hot-carrier diode10 mA is the typical operating current of an LEDAt absolute zero temperature, a semiconductor behaves as a/aninsulatorAvalance breakdown in a semiconductor take place when reversbias exceeds a certain value

Anotron a cold-cathode glow-discharge diode having a copperanode and a large cathode of sodium or other materialBARITT diode A microwave diode in which the carriers thattransverse the drift region are generated by minority carrierinjection from a forward-biased junction instead of being extractefrom the plasma of an avalanche regionA voltage multiplieris an electric circuit that converts AC to DCbut where the DC output peak value can be greater than the ACinput peak valueThe charge of a hole is equal to that of a proton

it is the current gain for the common-emitter configurationAn emitter resistor is used for biasing a bipolar junctiontransistorin most amplifier circuitsLoad line is a line drawn between the open-circuit voltage and thshort-circuit current on a JFET characteristic curveAnother name for a photoconductive cell isphotoresistivedeviceWhen both the emitter and collector junctions are reverse biased,the transistor is said to be at cut-offregionVaractor diode a type of diode used for tuning receivers and isnormally operated with reverse bias and derived its name fromvoltage variable capacitorBinistor A silicon npn tetrode that serves as a bistable negativeresistance deviceSpacistor a multiple-terminal solid-state device similar to atransistor that generates frequencies up to about 10,000 MHz byinjecting electrons or holes into a space-charge layer which rapid

forces these carriers to a collecting electrode.Silicon is nota good conductor1.5 Vis the approximate voltage drop of LEDUnder standard condition, pure germanium has a resistitivity of6ohm-cmThe holding of one extreme amplitude of the input waveform to acertain amount of potential is called clampingClamper is also known as DC restorerPercentage ripple can be calculated by getting the ratio of the avoltage to dc voltage and multiplying the result by 100%Silicon has the smallest leakage currentRecombination refers to annihilation of a hole and electron

Zener and avalanche effects are the two possible breakdownmechanism in pn junction diodes


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Zener breakdown occurs in pn diodes when the electric field inthe depletion layer increases to the point where it can breakcovalent bonds and generate electron hole pairsThe amount of additional energy required to emit an electron fromthe surface of a metal is called work functionWhen the temperature of a pure semiconductor is increased, itsresistances decrease.As a general rule, holes are found only in semiconductorsHole in a semiconductor is defined as the incomplete part of anelectron pair bondWhen the number of free electrons is increased in dopedsemiconductor, it becomes a n type semiconductorReducing the number of free electrons in a doped semiconductor

forms ap type semiconductorPure semiconductor atoms contain4 valence electronsAn acceptor atom contains 3 valence electronsThe resistivity of an extrinsic semiconductor is 2 ohm-cmThe forward resistance of a crystal diode is in the order ofohm1 is the ideal value of stability factor1.6726 x 10^-27 kg is the approximate mass of an atom at restApproximate mass at rest of a proton is equalto that of a neutronCharge of an electron is approximately equal to -1.6022 x 10^-19CElectrolytic capacitors are used in transistor amplifiersThe reason why a common collector is used for impedancematching is because its input impedance is very highIn power supplies, circuits that are employed in separating the acand dc components and bypass the ac components around theload, or prevent their generation are called series capacitors

Isotopes nuclei with common number of protons, but withdifferent number of neutronsFET has a high input impedance because its input is reversebiasedA MOSFET is sometimes called insulatedgate FETAn advantage of a MOSFET over a BJT in an RF amplifier circuit islow noiseThe voltage gain of an emitter follower circuit is lowA transistoris considered a current controlled deviceA FETis considered a voltage controlled deviceThe value of coupling capacitor, Cc n RC coupling is about 10 FFET has a pinch-off voltage of about 5 VLuminous efficacy a measure of the ability of an LED toproduce the desired number of lumens generated per applied wattof electrical energyPhotoconductive effect means the increased conductivity of anilluminated semiconductor junctionWhen light strikes on a photoconductive material theconductivity of the material increasesVaractor diode a type of diode used for tuning receivers;operate with reverse bias and derived its name from voltage-variable capacitorGallium arsenide semiconductor material is used in theconstruction of LED

Atomic mass is approximately the sum of the number of protonsand neutrons of an atom

Atomic numberis the number of protons in the nucleus or thenumber of electrons in an atomThe charge of a proton has the same value to that of an electronbut opposite in signMass of proton or neutron is 1,836 times that of an electronLAD a photodiode which conducts current only when forwardbiased and is exposed to light

Redis the most commonly used color for an LEDIf the temperature of a semiconductor material increases, thenumber of free electrons increasesVaractor diodes transition capacitance is directly proportional tothe product of the permittivity of the semiconductor material andthe PN junction area but inversely proportional to its depletionwidthAphotodiode is a light-sensitive device whose number of freeelectrons generated is proportional to the intensity of the incidentlight.Scale current another name for saturation current in a diode,which arises from the fact that it is directly proportional to thecross-sectional area of the diodeIn an amplifier, the emitter junction is forward biasedThe principal characteristic of a zener diode is the constantvoltage under conditions of varying current

Varactor diode a device whose internal capacitance varies witthe applied voltageThe common collectortransistor configuration has the highestvalue of input resistanceCoupling the method of connecting amplifier in cascadeCollectoris the largest region of a bipolar transistorTunnel diode A diode that has a negative resistance region andwidely used in the design of oscillators, switching networks andpulse generators.Diac refers to a three layer diode

Zener diode diode that operates in the reverse breakdownvoltage and is used as a voltage regulatorIGFET Another name for a metal-oxide semiconductor field effe

transistorIn enhancement-type MOSFET, the saturation region is used ifthe FET is to operate as an amplifierIn enhancement-type MOSFET, the triode and saturation regionare used for operation as a switchUnijunction transistor has three terminals, namely base 1, base and emitterSilicon and germanium semiconductor devices exhibit bothmetallic and nonmetallic characteristicsThe voltage drop across the diode remains relatively constantwhen current flow increases rapidly in a forward-biased diodeFree electrons are the majority current carriers in the N-typesiliconA LED is a diode that gives off light when energizedIR emitters are solid state gallium arsenide devices that emit abeam of radiant flux when forward biased

Input characteristic curve a graphical representation intransistor wherein the emitter current is plotted against thevariable emitter base voltage Veb for constant value of collector-base voltage VcbWhen the collector current Ic is plotted against the collector basevoltage at constant emitter current Ie, the curve obtained is calledoutput characteristic curveEg for silicon is 1.12 eV and for germanium is .072 eV. It can beconcluded that less number of electron hole pairs will begenerated in silicon than in germanium at roomtemperatureJunction diodes are commonly rated by its maximum forwardcurrent and PIVA special type of diode which is often used in RF switches,attenuators, and various types of phase shifting device is calledPIN diodeOutput characteristic A volt-ampere characteristics curve thadescribes the relationship of the output voltage of a transistor to output current at a set input currentThe use ofRC coupling is particularly desirable in low level, lownoise audio amplifier stages to minimize hum pick up from straymagnetic fieldsThe way in which the gain of an amplifier varies with the frequencis called frequency responseThe maximum rectification efficiency of a half wave rectifier is40.6 %The maximum rectification efficiency of a full-wave rectifier is 81.%Transformer coupling a coupled amplifier which has the majoadvantage of permitting power to be transformed from therelatively high output impedance of the first stage to the relativellow input impedance of the second stageElectron mobility property of silicon at 300 K is approximately

equal to 0.135 m^2/v-sIn a push-pull power amplifier, an input transformer can be used aaphase-splitterproviding equal amplitude input signals oppositin polarityIf the line frequency is 60Hz, the output frequency of a bridgerectifier is 120 HzFETis considered a unipolar deviceHarold Black invented the feedback amplifier in 1928The arrow in semiconductor symbols always point toward the Nregion and away from the P regionIf the input power of a half wave rectifier has a frequency of 400Hz, then the ripple frequency will be equal to400 HzIf the input frequency of a full-wave rectifier is 400 Hz, the ripplefrequency will be twice as great as the input frequencyCommon emitter circuit also called as the conventionalamplifier


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Another name for a light activated diode (LAD) isphotodiodeThe semiconductor device that radiate light or utilize light arecalled optoelectronic devicesStructural category of a semiconductor diodes can be either

junction and point contactZener diodes can be primarily classified as voltage regulationand voltage referenceThe principal characteristic of a tunnel diode is a negativeresistance regionVaractor diode a special type of semiconductor diode whichvaries its internal capacitance as the voltage applied to its terminalvariesThe maximum forward current in a junction diode is limited by its

junction temperatureWhen a transistor is fully saturated the collector current is atits maximum valueA FET without a channel and no current occurs with zero gatevoltage is enhancement-mode FETFET and CMOS devices are susceptible to damage from staticcharges

JFETs are often called square law devicesEquivalent of transistor at saturation in JFETs is constant-currentWhen a JFET is cut-off, the depletion layers are touchingThe voltage that turns on an enhancement-mode device is thethreshold voltageDepletion-mode MOSFET acts mostly as a JFETJFETs input impedance approaches infinityThe current gain of an emitter follower circuit is highThe drift transistor has a high frequency cut offdue to its low

inherent internal capacitance and low electron transit timethrough the baseThe maximum operating frequency of a transistor should be 50percent of the frequency cut-off of the transistor to ensure bestperformanceWhen transistor applications call for a temperature operatingcondition which exceeds 185 F, Silicon element is most suitableHeat dissipation is the most important factor of a powertransistorWhen the electron transmit time through the base region is veryshort, thisprovides higher cut-off frequencyWhen the transistors are used in video amplifiers, its mainlimitation ispoor frequency responseImpedance matching in circuit is important for maximum transferof energyA unijunction transistor is a three-terminal device consisting oftwosemiconductor layersIonization the process by which atoms are constantly losing andregaining free electronsParasitic oscillations termed as unwanted oscillation that mayoccur in almost any type of circuits, oscillator, amplifier, powersupply, receiver and transmitters.Linear amplifier an RF amplifier which will amplify a weak signalvoltage in relatively the same proportion as it will amplify astronger signal voltagePeak inverse voltage it is the maximum amount of reversevoltage which can be applied on a diode before the breakdownpoint is reachedElement it refers to any of the over 100 different substanceswhich have never been separated into simpler substances bychemical means and which alone or in combination constitute allmatterLED it is also known as a solid state lamp which utilizes the fall of

electron from the conduction level to the valence level to developan energy release in the form of heat or lightPresent atomic theories place the mass and positive charge of anatom in a central nucleus composed of protons and neutronsThephotons as fundamental particle is considered as a bundle ofradiant energy or light, the amount of energy being related to thefrequencyElectron emitted by the mechanical impact of an iron striking asurface is called secondary electronsThe break up of nuclei into nuclear fragments that are themselvesnuclei is called fissionNeutrinos - Particles of zero charge and zero mass9.1096 x 10^-31 kg approximate mass of an electron at restValence shell term used to describe the outermost shell of anatom

Free electrons are the electrons at the outermost shell whichare usually weakly attracted by the core such that an outside forccan easily dislodge these electrons from the atomThe reason why electrons are not pulled in the positive chargednucleus is because of the centrifugal force which usually becamexactly equals the inward attraction of the nucleusValence band the highest energy band of an atom which can bfilled with electronsConduction band an energy band in which electrons can movefreelyGoldis considered as the best conductorCrystal it is an arrangement of silicon atom combine to form asolid such that there are now 8 electrons in the valence shell

Covalent bond the sharing of valence electrons to produce achemically stable atomBound electrons the eight electrons which are tightly held bythe atomWhen an atom has bound electrons, it is described as filled orsaturated since valence orbit can hold not more than 8electrons

Ambient temperature refers to the temperature of thesurrounding airFree electrons the term used to describe the released electrondislodged form its original shell due to increase in temperaturewhich joins into a larger orbitHole the term used to refer to the vacancy left by the freeelectron when it departs from its original shellRecombination the merging of a free electron and a hole insidthe silicon crystal

Lifetime the amount of time between the creation anddisappearance of a free electronThe purpose of adding an impurity atom to an intrinsic crystal is tincrease its electric conductivityAn extrinsic semiconductor produced n-type when a pentavalentatom are added to the molten siliconPhosphorus, antimony and arsenic are pentavalent atomP-type an extrinsic semiconductor which is produced when atrivalent atom are added to the molten siliconLinear power derating factor the reduction of power handlincapability of the diode due to the increase of ambient temperaturform room temperatureMaximum junction temperature the maximum temperaturethe diode can operate before burningReverse recovery time of the diode is computed as the sum of thstorage time and transition interval from the forward to reversebiasThermal energycauses intrinsic semiconductor to have someholesWhen a diode is forward biased, the recombination of freeelectrons and hole may produce heat, light & radiationPhosphorous doping element has a valence of 5Silicon doping element has a valence of 4Boron doping element has a valence of 3Proton it is a stable positive charge in the nucleus that is notfree to move.Hole a positive charge outside the nucleus which is present onlyin semiconductor due to unfilled covalent bondsWhen charges are forced to move by the electric field of a potentdifference, driftcurrent is said to flowWhen a PN junction is connected to a battery in such a way that Pside is connected to positive terminal of the battery and negativeterminal to N-side, this connection is known as forward bias

When a PN junction is connected to a battery in such a way that Pside is connected to negative terminal of the battery and positiveterminal to N-side, this connection is known as reverse biasAn electron in the conduction band has higher energy then theelectron in the valence bandAn ideal diode should have zero resistance in the forwardbias and an infinitely large resistance in reverse biasThermal voltage is approximately equal to 25 mVat roomtemperatureBoltzmanns constant is equivalent to 8.62 x 10^-5 eV/KThe preferred form of biasing a JFET amplifier is through the selfbiasThe gate-to-source on voltage of an n-channel enhancement modMOSFET is greater then Vgs


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Carrier drift a mechanism for carrier motion in semiconductorswhich occurs when an electric field is applied across a piece ofsilicon

Avalanche breakdown occurs in pn diodes when the minoritycarriers that cross the depletion region under the influence of theelectric field, gain sufficient kinetic energy to be able to breakcovalent bonds in atoms with which they collide


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ELECTRONIC CIRCUITS

Class A amplifierhas an output current flowing during the wholeinput current cycle.

If a transistor amplifier provides a 360output signal, it is classifiedas class A

Class B an amplifier that delivers an output signal of 180 only

Class AB a class of amplifiers wherein the output signal swings

more than 180but less than 360

The distinguishing feature of class C amplifier is that the output ispresent for less than 180 degrees of the input signal cycle

Class C a full 360 sine-wave signal is applied as an input to anunknown class of amplifier, if the output delivers only a pulse of

less than 180

Class D amplifiers are intended for pulse operation

Class S amplifier are used to amplify either amplitude modulated(AM) or frequency modulated (PM) signal

Class D amplifier has the highest efficiency

25% is the efficiency of a series-fed class A amplifier

A class A amplifier has an efficiency of only 25%, but this can beincreased if the output is coupled with a transformer. Up to 50%efficiency will be reached due to coupling

Class B amplifiers deliver an output signal of 180 and have amaximum efficiency of78.5%

Transistorized class C power amplifier will usually have anefficiency of33%

For pulse-amplification, class D amplifier is mostly used. Class Damplifier efficiency reaches over 90%

Efficiency of class AB is in between the efficiency of class A and B,that is from 25% - 78.5%

Class A (transformer-coupled) is the most effient

In order to have the best efficiency and stability, the loadline of asolid state power amplifier be operatedjust below thesaturation point

In most transistor class A amplifier, the quiescent point is set at thecenterFor a class B amplifier, the operating point or Q-point is set atcutoff

The Q-point for class A amplifier is at the active region, for class Bit is at cutoff region, while for class AB is slightly above cutoff

The Q-point of a class C amplifier is positioned below cutoffregion

Class C amplifiers are considered as non-linear

Class A or B amplifiers can be used for linear amplification

Class BC amplifier is biased to class C but modulates over thesame portion of the curve as if it ware biased to class B

Transformer-coupled push-pull amplifier two class Bamplifiers connected such that one amplifies the positive cycle andthe other amplifies the remaining negative cycle. Both outputsignals are then coupled by a transformer to the load

Complementary-symmetry amplifier a push-pull amplifierthat uses npn and pnp transistors to amplify the positive andnegative cycles respectively

Quasi-complementary push-pull amplifier a push pullamplifier that uses either npn or pnp as its final stage. The circuitconfiguration looks like the complementary-symmetry

Class A amplifier has the least distortion

Nonlinear distortion a type of distortion wherein the outputsignal does not have the desired linear relation to the input

Amplitude distortion Distortion that is due to the inability of aamplifier to amplify equally well all the frequencies present at theinput signal

Harmonic distortion a nonlinear distortion in which the outputconsists of undesired harmonic frequencies of the input signal

The overall gain of an amplifier in cascade is the product

Cascaded amplifier a multistage transistor amplifier arrangedin a conventional series manner, the output of one stage isforward-coupled to the next stage

Darlington configuration a direct-coupled two-stage transistoconfiguration wherein the output of the first transistor is directlycoupled and amplified by the second transistor. This configurationgives a very high current gain

Cascode configuration a two-stage transistor amplifier in whithe output collector of the first stage provides input to the emitte

of the second stage. The final output is then taken from thecollector of the second stage

Cascode amplifier famous transistor amplifier configurationdesigned to eliminate the so called Miller effect

Common-emitter and common-base transistor configuration iused in a cascode amplifier

Darlington transistor configuration known to have a super-beta

1.6 Vis the approximate threshold voltage between the base-emitter junction of a silicon darlington transistor

Feedback pair transistor arrangement that operates like adarlington but uses a combination of pnp and npn transistorsinstead of both npn

Differential amplifier an amplifier basically constructed fromtwo transistor and whose output is proportional to the differencebetween the voltages applied to its two inputs

Operational amplifier (op-amp) an amplifier having highdirect-current stability and high immunity to oscillation, this isinitially used to perform analog-computer functions such assumming and integrating.

Op-amp one of the most versatile and widely used electronicdevice in linear applications

Op-amp it is a very high-gain differential amplifier with very higinput impedance and very low output impedance

An operational amplifier must have at least 5 usable terminals

Differential amplifier the circuit at the input stage ofoperational amplifiers

Differential amplifier an amplifier whose output is proportionto the difference between the voltages applied to its two inputs

In op-amps functional block diagram, high gain amplifierfollowthe differential amplifier

A good op-amp has a very high input resistance

Ideally, op-amps have infinite input resistance andzero outputresistance


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The input of an op-amp is made high by using super betatransistor at the input differential stage or by using FETs atthe input differential stage

Complementary amplifieris commonly used at the output stageof op-amps

Common collector the transistor configuration used at theoutput complementary stage of most op-amps

Most op-amps use a common collector at the output stage to havea very low output resistanceLevel shifter the stage followed by the output complementary in

op amps functional block diagram

The purpose of level shifter in op-amps is to set and/or adjustthe output voltage to zero when the input signal is zero

Primarily, op-amps are operated with bipolar power supply,however, we can also use single polarity power supply bygenerating a reference voltage above ground

When the same signal is applied to both inverting and non-inverting input terminals of an ideal op-amp, the output voltagewould bezero V

Common mode the operating mode of an op-amp, when bothinputs are tied together or when the input signal is common to bothinputs

Common gain the gain of an op-amp if operated in commonmode inputWhen one input of the op-amp is connected to ground and theother is to the signal source, its operation is called single-endedinput

If op-amps are operated in differential mode, its gain is technicallytermed as differential gain

Open-loop gain is the highest

Common-mode rejection ratio the ratio of the differential gainand common gain of an op-amp

+VSAT to VSATis the maximum output voltage swing of an op-amp

Input bias current- the current needed at the input of an op-ampto operate it normally

Ideal op-amp requires no input current, but real op-amp needs avery small input current called input bias current. At both inputs,the bias currents have a slight difference. Its difference is calledinput offset current

Input offset current drift the change in input offset currentdue to temperature change

The reason why a slight difference between the input bias currentoccurs in op-amp is due to the unsymmetrical circuit componentparameters. This unsymmetrical condition also produces adifference in input voltage called input offset voltage

In op-amps, input offset voltagedriftis the change in inputoffset voltage due to the change in temperature

Ideally, the output voltage of an op-amp is zero when there is noinput signal, however, in practical circuit, a small output voltageappears, this voltage is known as output offset voltage

The output offset voltage of an op-amp are due to input offsetcurrent and input offset voltage

You minimize the output offset voltage due to the input offsetcurrent of an op-amp by installing a bias-current-compensating resistor

The approximate value of the bias-current compensating resistor op-amp circuit is equal to the parallel combination of theinput and feedback resistors

In op-amp analysis, the input offset voltage is represented by abattery

The battery representing the input offset voltage in op-amp circuanalysis is connected between the non-inverting and groundterminal

The effect of the input offset voltage to the output voltage if theop-amp has no feedback element is it causes the output to

saturate either towards positive or negative

By making the feedback resistance smallwe can minimize theffect of the input offset current and input offset voltage at theoutput offset voltage

The most effective way of minimizing the output offset voltage ofan op-mp is by properly using and adjusting the offset-nullterminals

Slew rate op-amp parameter(s) that is important in large signadc amplificationIn large signal dc-amplifiers using op-amp, driftparameter has thleast effect on its performance

For ac-amplifiers using op-amps, slew rate and frequency

response parameters can affect its performance

If an op-amp is used to amplify small ac-signals, frequencyresponse parameter should greatly consider to ensure betterperformance

Internally compensated op-amps op-amps with internalfrequency compensation capacitor to prevent oscillation

Break frequency the frequency at which the open-loop gain ofan op-amp is 0.707 times its value at very low frequency

The voltage gain of op-amp will decrease when its operatingfrequency is increased

Roll-off the reduction of op-amps gain due to increase operatinfrequency

20dB/decade roll-off a gain reduction by a factor of 10 perdecade

6 dB/octave a reduction of op-amps voltage gain by a factor otwo each time the frequency doubles

Unity-gain bandwidth product frequency at which the voltaggain of op-amp reduces to unity.

Rise time is defined as the time required for the output voltage torise from 10% to 90% of its final value

Slew rate the maximum output voltage rate of change of an opamp

Factors or parameters that determine the op-amps maximumoperating temperature: slew rate and unity-gain bandwidth

product

When an op-amp is used as a comparator, the output voltagewould be +VSAT ifV+ > V-

Window comparator two comparators using op-amps,configured such that it can detect voltage levels within a certainrange of values rather than simply comparing whether a voltage above or below a certain reference

Open-loop gain is significant when an op-amp is used as avoltage comparator


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An op-amp zero-crossing detector without hysteresis, has no feedback

The feed back element of a differentiator constructed from op-ampis a resistor

An active integrator uses an op-amp, capacitoris its feedbackelement

Unity the voltage gain of an op-amp voltage follower

The noise gain of op-amps is 1 + Rf/Ri

Making both the feedback and input resistances as small aspossible resistor combination provides lesser noise in op-ampcircuits

In most ac-amplifiers using op-amps, the feedback resistor isshunted with a very small capacitance to minimize highfrequency noise

Externally compensated op-amps are op-amps with frequency-compensation terminals or op-amps with provision toexternally compensate for frequency stability

In the external frequency-compensation capacitor, the lower itsvalue, the wider is its bandwidth

Typical value of the external frequency-compensating capacitor of

op-amps is about 3.0 30 F

General purpose op-amps are op-amps with limited unity-gainbandwidth up to approximately 1 MHz or op-amps with slewrate about 0.5V/secHigh-frequency, high-slew rate op-amps Op-amps designedto operate at high slew rate, about 2000 V/micosec and at highfrequencies, more than 50 MHz

Generally, hybrid op-amps found its application for high-outputvoltage and for high-output current

0.2 mV the magnitude of the op-amps input offset voltage beforeit can be classified as a low-input offset voltage op-amp

Op-amps whose internal transistor biasing can be controlledexternally are categorize asprogrammable op-amps

Metal can correspond to TO-99

Dual-in-line or DIL package is designed as TO-116

SMT for high density ICs involving many op-amps

PLCCs, SOICs, LCCCs are examples of surface-mountedtechnology (SMT) device

For a circuit to oscillate, it must have a positive feedbacksufficient to overcome losses.

Oscillator Circuits that produces alternating or pulsating currentor voltage

Hartleyoscillator circuit uses a tapped coil in the tuned circuit

The size and thickness of the crystal materialdetermines theresonant frequency of a crystal

Relaxation oscillator type of oscillator whose frequency isdependent on the charge and discharge of RC network

Klystron oscillator a microwave oscillator

Colpitts oscillator a self-excited oscillator in which the tank isdivided into input and feedback portions by a capacitive voltagedivider

Hartley oscillator A self-excited oscillator in which the tank isdivided into input and feedback portions by an inductive voltagedivider or a tapped coil

Multivibrator a circuit usually containing two transistors ortubes in an RC-coulped amplifier, the two active devices switcheach other alternately on and off

Monostable a multivibrator that generates one output pulse foeach input trigger pulse

Monostable mutlivibrator is also known as one shot or singleshot

Resistor and capacitor combinations determines the pulsetime in a monostable multivibrator

Bistable a multivibrator having two stable state

Bistable multivibratoris also known as Eccles/Jordan circuit

Flip-flop is actually a bistable multivibrator

Astable considered as a free-running multivibrator


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Electronic (Audio/RF) Circuit / Analysis/ Design

Class A and B are considered linear amplifier

The voltage gain of a common collector configuration is unity

A two-transistor class B power amplifier is commonly calledpush-pull amplifier

If a transistor is operated in such a way that output current flows

for 160of the input signal, then it is Class C operation

Directcoupling has the best frequency response

A transistor amplifier has high output impedance becausecollector has reverse bias

Gain-bandwidth productis considered an amplifier figure ofmerit

Logic probe a piece of equipment in an oscilloscope use toindicate pulse condition in a digital logic circuit

Comparator a linear circuit that compares two input signals andprovides a digital level output depending on the relationship of theinput signals

Transformercoupling is generally used in power amplifiers

Class A amplifiers output current flows for the entire cycle

The coupling capacitor must be large enough topreventattenuation of low frequencyin an RC coupling scheme

Operating pointis the point of intersection of dc and ac load lines

An oscillator produces undampedoscillations

Quiescent pointis the operating point in the characteristic curve

Oscillators operate on the principle ofpositive feedback

In a class A amplifier, the output signal is the same as the input

Biasing condition will change if the input capacitor of atransistor amplifier is short-circuited

Biasing is used to establish a fixed level of current or voltage in atransistor

Class C power amplifier has the highest collector efficiency

Class C is a non-linear type of amplifier

An AF transformer is shielded toprevent induction due to straymagnetic fields

Amplitude distortion is otherwise known as harmonic distortion

Hie represents common-emitter small signal input resistance

The ear is not sensitive to frequencydistortion

Class C is an amplifier whose output current flow for less thanone-half the entire input cycle

If gain without feedback and feedback factor are A and Betarespectively, then gain with negative feedback is given byA/

(1+A )

The collector current in a common base configuration is equal toalpha times emitter current plus leakage current

The value of collector load resistance in a transistor amplifier isless than the output impedance of the transistor

The purpose of RC or transformer coupling is to separate bias ofone stage from another

The bandwidth of a single stage amplifier is more than that ofmultistage amplifier

Transit time is the time taken by the electrons or holes to passfrom the emitter to the collector

To obtain good gain stability in a negative feedback amplifier, Ais very much greater than 1

The basic concept of the electric wave filter was originated byCampbell and Wagner

Common-base configuration has the lowest current gain

Common-base and Common-collectortransistor configurationoffers no phase reversal at the output

The number of stages that can be directly coupled is limitedbecause change in temperature can cause thermalinstability

The input capacitor in an amplifier is called coupling capacitor

AC load line has a/an biggerslope compared to that of dc load lin

A multistage amplifier uses at least two transistors

RC coupling is used for voltage amplification

An ammeters ideal resistance should bezero

Amplifieris the circuit that can increase the peak-to-peak voltagcurrent or power of a signal

When the non-linear distortion in an amplifier is D without

feedback, with negative voltage feedback it will be D/(1+A )

A tuned amplifier uses LC tankload

The voltage gain over mid-frequency range in an RC coupledamplifier is constant

The input impedance of an amplifier increases when negativevoltage feedback is applied

The input impedance of an amplifier decreases when negativecurrent feedback is applied

To obtain the frequency response curve of an amplifier generatooutput levelis kept constant

Relaxation oscillator a type of oscillator wherein the frequencis determined by the charge and discharge of resistor-capacitornetworks used in conjunction with amplifiers or similar devices

The driver transformer has center-tapped secondary to provide

two signals 180 out of phase to transistors of push-pullcircuit

The advantage of RC coupling scheme is economy

A type of filter which have a single continuous transmission bandwith neither the upper nor the lower cut-off frequencies being zeror infinite is called band pass filter

GPS an instrument use to measure ones location in terms ofcoordinates

Transformer coupling is used forpoweramplification

The typical value of coupling capacitor in RC coupling is about 10F

An electronic transfer from one stage to the next is termed ascoupling


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An amplifier configuration where the input signal is fed to theemitter terminal and the output from the collector terminal iscalled common base

If the noise factor of an ideal amplifier expressed in dB, then it is 0

A feedback circuit is independent offrequency

The basic purpose of applying negative feedback to an amplifier isto reduce distortion

The capacitors are considered open in the dc equivalent circuit ofa transistor amplifier

10 kHz frequency produces the highest noise factor

Power amplifier handle large signals

The operating point is generally located at the middle of dc loadline in class A operation

Low voltage gain describes a common collector amplifier

The general characteristics of a common base amplifier are highvoltage gain, low current gain, high power gain and verylow input resistance

To amplify dc signal, multistage amplifier uses Directcoupling

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