1 Basic Electronics

8/8/2019 1 Basic Electronics

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Electrical Fundamentals


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MATTER

Everything in the world is made of matter. Matter is

anything that has mass (weight) and occupies space.Matter can be made up of a group or series of differentatoms to form a molecule. These groups of atoms(molecules) are sometimes called compounds. Sometypes of matter can be broken down to a single atom

while still maintaining the properties of the originalmaterial. These types of material are called elements.

Matter has three states: Solid, Liquid, and Vapor.


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MOLECULE EXAMPLE

Imagine a lake. Now imagine taking the

smallest particle or piece of water from thelake. You would have a single molecule ofwater, H

2O, which is made up of two

hydrogen atoms and one oxygen atom.

Not all materials are made up of molecules.Copper, for example, is made up of a singlecopper atom. These are called elements.Each element is a type of matter that has

certain individual characteristics.


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THE ATOMOne of the basic building blocks in the universe formatter is the atom. All matter - gas, liquid, or solid -is made up of molecules or atoms joined together.These atoms are the smallest particle into which an

element or substance can be divided without losingits property.

A single atom consists of three basic components: aproton, a neutron, and an electron.

Within the atom there is a Nucleus. The Nucleus

contains the protons and neutrons. Orbiting aroundthe nucleus are the electrons.

An atom is similar to a miniature solar system. Aswith the sun in the center of the universe, thenucleus is in the center of the atom. Protons and

Neutrons are contained inside the nucleus. Orbitingaround the nucleus are the electrons.


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ATOM CONSTRUCTIONAn atom is similar to aminiature solar system. As the

sun is in the center of thesolar system, so is the nucleusis in the center of the atom.Protons and neutrons are

contained within the nucleus.Electrons orbit around thenucleus, which would besimilar to planets orbitingaround the sun.


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NUCLEUS

The Nucleus is located in thecenter of the atom (shown inred).The Nucleus contains theprotons and neutrons.

Orbiting around the nucleusare the electrons.



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PROTONSProtons are located within thenucleus of the atom (shown in blue).

Protons are positively (+) charged.

NEUTRONS

Neutrons add atomic weight to anatom (shown in green).

Neutrons have no electrical charge.


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ELECTRONSElectrons orbit around the nucleus of theatom (shown in yellow).

Electrons are negatively (-) charged.

Since electrons are lighter than protons andare outside the nucleus, they can be easilymoved from atom to atom to form a flow ofelectrons. Normally electrons are preventedfrom being pulled into the atom by the

forward momentum of their rotation.Electrons are also prevented from flyingaway because of the magnetic attraction ofthe protons inside the nucleus, the sametype of force that keeps the planets orbiting

around the sun.


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ELECTRICAL CHARGES

Opposite electrical charges always attract eachother. So these particles with opposite charges willtend to move toward each other. Like electricalcharges always repel. So particles with like chargeswill move away from each other.

Remember: Opposites charges attract, and likecharges repel.

Atoms always try to remain electrically balanced.


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BALANCED ATOMS

Atoms normally have an equal number of

electrons and protons.Atoms have no electrical charge. They areneither positive nor negative. They areelectrically neutral or BALANCED.Thenegative charge of the electrons will

cancel the positive charge of the protons,thus balancing the charge of the atom.

This cancellation of charges creates anatural attraction or bonding between thepositive proton and the negative electron.


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ION PARTICLESWhen an atom loses or gains anelectron, an imbalance occurs.

The atom becomes either apositively or negatively chargedparticle called an ION. Theseunbalanced charged IONparticles are responsible forelectron flow (electricity).

IONs will take or release an

electron to become balancedagain.


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ION CHARGEA positive (+) ION has oneless electron than it hasprotons.

A negative (-) ION has onemore electron than it hasprotons.

The positive ION attracts anegative ION to becomebalanced. This attraction ordifference in electricalpotential causes electron flow.


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ELECTRON ORBITS

Electrons rotate around theatom at different orbits called

Rings, Orbits, or Shells.

BOUND ELECTRONS orbit thenucleus on the inner rings.Bound electrons have a strong

magnetic attraction to thenucleus.

FREE ELECTRONS orbit on theoutermost ring which is knownas the VALANCE RING.


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FREE ELECTRONS

Only the FREE ELECTRONS in theoutermost shell (Valance Ring) are free to

move from atom to atom. This movement

is called ELECTRON FLOW.

These FREE ELECTRONS are loosely

held and can easily be moved to another

atom or ion.

Because of their distance from thenucleus, free electrons have a weak

magnetic attraction. Since this attraction is

not as strong to the nucleus as the bound

electrons on the inner orbits, the electronsmove easil from atom to atom.

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INSULATORSAn INSULATOR is any material that

inhibits (stops) the flow of electrons(electricity).

An insulator is any material with 5 to 8

free electrons in the outer ring.Because, atoms with 5 to 8 electronsin the outer ring are held (bound)tightly to the atom, they CANNOT beeasily moved to another atom nor

make room for more electrons.

Insulator material includes glass,rubber, and plastic.


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CONDUCTORS

A CONDUCTOR is any material thateasily allows electrons (electricity) toflow.

A CONDUCTOR has 1 to 3 freeelectrons in the outerring.Because atoms with 1 to 3electrons in the outer ring are held(bound) loosely to the atom, they

can easily move to another atom ormake room for more electrons.

Conductor material includes copper

and gold.

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SEMICONDUCTORSAny material with exactly 4

free electrons in the outer orbitare calledSEMICONDUCTORS.

A semiconductor is neither aconductor or insulator.semiconductor materialincludes carbon, silicon, andgermanium.

These materials are be used inthe manufacturer of diodes,transistors, and integrated

circuit chips.

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Two Current Flow theories exist. The first is:

ELECTRON THEORYThe Electron Theory states that current flowsfrom NEGATIVE to POSITIVE. Electrons move

from atom to atom as they move through theconductor towards positive.


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The second Current Flow theory is:

CONVENTIONAL THEORYConventional theory, also known as HOLE THEORY,states that current flows from POSITIVE to NEGATIVE.Protons or the lack of electrons (the holes) movetowards the negative. (Current flow direction in HoleTheory is the opposite of that in Electron Theory.)


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VOLTAGEVoltage is the electrical force that moves electronsthrough a conductor. Voltage is electrical pressurealso known as EMF (Electro Motive Force) thatpushes electrons.

The greater the difference in electrical potentialpush (difference between positive and negative),the greater the voltage force potential.


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MEASUREMENTA VOLTMETER measures thevoltage potential across orparallel to the circuit.

The Voltmeter measures theamount of electrical pressuredifference between two pointsbeing measured.

Voltage can exist betweentwo points without electronflow.


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VOLTAGE UNITSVoltage is measured in units called VOLTS.Voltage measurements can use different valueprefixes such as millivolt, volt, Kilovolt, andMegavolt.

VOLTAGE LESS THANBASE UNIT

BASIC UNIT LARGER THANBASE UNIT

Symbol mV V kV

Pronounced millivolt Volt Kilovolt

Multiplier 0.001 1 1,000



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CURRENT (AMPERES)

CURRENT is the quantity or flow rate of electrons

moving past a point within one second. Current flow isalso known as amperage, or amps for short.Higher voltage will produce higher current flow, andlower voltage will produce lower current flow.


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MEASUREMENTAn AMMETER measures the quantity of current flow.Ammeters are placed in series (inline) to count theelectrons passing through it.

Example: A water meter counts the gallons of waterflowing through it.

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AMPERAGE LESS THAN

BASE UNITLESS THAN

BASE UNITBASIC UNIT

Symbol A mA A

Pronounced Microamp milliamp Amp

Multiplier 0.000001 0.001 1


AMPERAGE UNITSCurrent flow is measured in units called Amperes orAMPS.Amperage measurements can use different valueprefixes, such as microamp, milliamp, and Amp.



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AFFECTS OF CURRENT FLOW

Two common effects of current flow are Heat Generation andElectromagnetism.

HEAT: When current flows, heat will be generated. The higher

the current flow the greater the heat generated. An examplewould be a light bulb. If enough current flows across thefilament, it will glow white hot and illuminate to produce light.

ELECTROMAGNETISM: When current flows, a small magnetic

field is created. The higher the current flow, the stronger themagnetic field. An example: Electromagnetism principles areused in alternators, ignition systems, and other electronicdevices.



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RESISTANCEResistance is the force that reduces or stops theflow of electrons. It opposes voltage.Higher resistance will decrease the flow of electrons and

lower resistance will allow more electrons to flow.




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MEASUREMENTAn OHMMETER measures the resistance of an electrical

circuit or component. No voltage can be applied while theohmmeter is connected, or damage to the meter willoccur.Example: Water flows through a garden hose, andsomeone steps on the hose. The greater the pressureplaced on the hose, the greater the hose restriction andthe less water flows.




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AMPERAGE BASIC UNIT MORE THANBASE UNIT

MORE THANBASE UNIT

Symbol K M

Pronounced Ohm Kilo ohm Mega ohm

Multiplier 1 1,000 1,000,000


RESISTANCE UNITSResistance is measured in units called OHMS.Resistance measurements can use different valueprefixes, such as Kilo ohm and Megaohms.



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RESISTANCE FACTORS

Various factors can affect the resistance. These include:LENGTH of the conductor. The longer the conductor, thehigher the resistance.

DIAMETERof the conductor. The narrower theconductor, the higher the resistance.TEMPERATURE of the material. Depending on thematerial, most will increase resistance as temperatureincreases.

PHYSICAL CONDITION (DAMAGE) to the material.Any damage will increase resistance.TYPE of MATERIAL used. Various materials have a wide

range of resistances.



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TYPES OF ELECTRICITY

Two basic types of Electricity classifications:

STATIC ELECTRICITY is electricity that is standing still.Voltage potential with NO electron flow.

DYNAMIC ELECTRICITY is electricity that is in motion.Voltage potential WITH electron flow. Two types ofDynamic electricity exist:

Direct Current (DC) Electron Flow is in only onedirection.

Alternating Current (AC) Electron flow alternates andflows in both directions (back and forth).

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STATIC ELECTRICITY

Voltage potential with NO electron flow.Example: By rubbing a silk cloth on a glass rod, youphysically remove electrons from the glass rod and placethem on the cloth. The cloth now has a surplus of

electrons (negatively charged), and the rod now has adeficiency of electrons (positively charged).Another example: Rub your shoes on a rug and thentouch a metal table or chair .... Zap!! The shock you feltwas the static electricity dissipating through your body.

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DYNAMIC ELECTRICITYis electricity in motion, meaning you have electronsflowing, in other words voltage potential WITH electronflow.Two types of dynamic electricity exists:Direct Current (DC)Alternating Current (AC)




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DIRECT CURRENT (DC)Electricity with electrons flowing in only one directionis called Direct Current or DC.DC electrical systems are used in cars.




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ALTERNATING CURRENT (AC)

Electricity with electrons flowing back and forth,negative - positive- negative, is called AlternatingCurrent, or AC.

The electrical appliances in your home use AC power.




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SOURCES OF ELECTRICITY

Electricity can be created by several means: Friction, Heat, Light,

Pressure, Chemical Action, or Magnetic Action.Only a few of these sources of energy are used in the

automobile. The battery produces electricity through chemical

action, and the alternator produces electricity through magnetic

action.

Friction creates static electricity.Heat can act upon a device called a thermo couple to create DC.

Light applied to photoelectric materials will produce DC

electricity.

Pressure applied to a piezoelectric material will produce DCelectricity.

Chemical Action of certain chemicals will create electricity.

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1 Basic Electronics