73432684 1 Basic Electronics

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Electrical Fundamentals




MATTER

Everything in the world is made of matter.

Matter is anything that has mass (weight) and occupies space.

Solid

Liquid

Vapor



Matter can be made up of molecules.

Molecules are sometimes calledcompounds.

Molecule is a group or series of different

atoms



A single atom consists of Nucleus and an electrons.

NUCLEUSThe Nucleus is located in thecenter of the atom

The Nucleus contains theprotons and neutrons.

Nucleus

Neutron

Proton

protons is positively Charged

Electron is Negatively Charged



ELECTRONS

Electrons orbit around the nucleus of the atom in elliptical shape (shownin yellow).

Electrons are negatively (-) charged.

Orbit is called as Ring or Shell




ELECTRONSSince electrons are lighter than protons andare outside the nucleus, they can be easilymoved from atom to atom to form a flow of electrons.

Normally electrons are prevented from beingpulled into the atom by the forwardmomentum of their rotation.

Electrons are also prevented from flying

away because of the magnetic attractionof the protons inside the nucleus




ELECTRICAL CHARGESOpposite electrical charges always attract eachother.

So these particles with opposite charges will tend tomove toward each other.

Like electrical charges always repel. So particles withlike charges will move away from each other.

Remember: Opposites charges attract, and likecharges repel.

Atoms always try to remain electrically balanced.



Atomic weight - The number of protons plus the number

of neutrons in the nucleus of an atom

Atomic Number - Number of electrons or protons in

an atom




BALANCED ATOMS

Atoms normally have an equalnumber of electrons and

protons.

Atoms have no electrical charge.

They are neither positive nor

negative.They are electrically neutral orBALANCED.




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

The atom becomes either apositively or negatively chargedparticle called an ION.

These unbalanced charged ION

particles are responsible forelectron flow (electricity).

IONs will take or release anelectron to become balanced again.




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 or difference in

electrical potential causeselectron flow.



Electrical Fundamentals 13 of 36

ELECTRON ORBITS

Electrons rotate around the atomat different orbits called Rings,

Orbits, or Shells.



BOUND ELECTRONS orbit the nucleus onthe inner rings. Bound electrons have a

strong magnetic attraction to the nucleus.

ELECTRONS in VALANCE RING isknown as the FREE ELECTRONS

The Outer Most Orbit is called

VALANCE RING or VALANCE

ORBIT



FREE ELECTRONSOnly the FREE ELECTRONS in the

outermost 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 the nucleus,

free electrons have a weak magneticattraction.

Since this attraction is not as strong to the

nucleus as the bound electrons on the inner

orbits, the electrons move easily from atom

to atom.

ElectricalFundamentals

14 of 36



An atom to Chemically stable,

8 electrons should be inValance ring

http://www.autoshop101.com/trainmodules/electricity/elec116.html



Any material has 5 to 7 free electrons in the outerring. Which is called INSULATORS

An INSULATOR is any material that inhibits (stops) the flow of electrons (electricity).





An insulator is any material with 5 to 7 free electronsin the outer ring.

Because, atoms with 5 to 7 electrons in the outerring are held (bound) tightly to the atom,they CANNOT be easily moved to another

atom nor make room for more electrons.



Insulator material includes

glass, rubber, and plastic.



CONDUCTORS

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

A CONDUCTOR has 1 to 3 freeelectrons in the outer ring.

Because atoms with 1 to 3 electrons inthe outer ring are held (bound) loosely

to the atom, they can easily move toanother atom or make room for moreelectrons.

Conductor material includes copperand gold.





SEMICONDUCTORSAny material with exactly 4 free

electrons in the outer orbit arecalled SEMICONDUCTORS.

A semiconductor is neither a

conductor or insulator.

semiconductor material includescarbon, silicon, andgermanium.

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

chips.







The Basic Electrical Quantities and their Units

Electrical Current

Potential Difference

Resistance



Electrical Current

The flow of electrons in one direction along anypath or around any circuit is called current

Symbol - I

Unit of Measurement - amp



CURRENT (AMPERES)

CURRENT is the quantity or flow rate of electronsmoving past a point within one second.

Current flow is also known as ampere, or amps for

short.

Higher voltage will produce higher current flow, andlower voltage will produce lower current flow.




In practical terms,

the ampere is a measure of the amount of electric charge passing a

point in an electric circuit per unit time with 6.241 × 1018 electrons,

or

one coulomb per second constituting one ampere




MEASUREMENT

An 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.




AMPERAGE LESS THAN

BASE UNIT LESS THAN

BASE UNIT BASIC UNIT

Symbol µA mA A

Pronounced Microamp milliamp Amp

Multiplier 0.000001 0.001 1


Amperage measurements can use different valueprefixes, such as microamp, milliamp, and Amp.





AFFECTS OF CURRENT FLOW

Two common effects of current flow are Heat Generation andElectromagnetism.

HEAT: When current flows, heat will be generated. The higherthe current flow the greater the heat generated.

An example would be a light bulb. If enough current flows acrossthe filament, it will glow white hot and illuminate to producelight.

ELECTROMAGNETISM: When current flows, a small magneticfield is created. The higher the current flow, the stronger themagnetic field.

An example: Electromagnetism principles are used in alternators,ignition systems, and other electronic devices.



Potential Difference or Voltage

It is the difference of electrical Potential between thetwo points in an electric circuit

Symbol - V

Unit of Measurement - Volts



VOLTAGE

Voltage is the electrical force that moves electronsthrough a conductor.

Voltage is electrical pressure also known as EMF(Electro Motive Force) that pushes electrons.

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


Voltage is electrical Pressure




MEASUREMENT

A VOLTMETER measures thevoltage potential across orparallel to the circuit.

The Voltmeter measures theamount of electrical pressuredifference between two

points being measured.




VOLTAGE UNITSVoltage is measured in units called VOLTS.

Voltage measurements can use different valueprefixes such as millivolt, volt, Kilovolt, and

Megavolt.

VOLTAGE LESS THAN

BASE UNIT BASIC UNIT LARGER THAN

BASE UNIT

Symbol mV V kV

Pronounced millivolt Volt Kilovolt

Multiplier 0.001 1 1,000





Resistance

The Property of a conductor which opposes theflow of electric current it is known as resistance

Symbol -

Unit of Measurement - Ohms




RESISTANCE

Resistance is the force that reduces or stops theflow of electrons.

It opposes voltage.

Higher resistance will decrease the flow of electrons andlower resistance will allow more electrons to flow.





MEASUREMENTAn OHMMETER measures the resistance of an electrical

circuit or component.No voltage can be applied while the ohmmeter isconnected, or damage to the meter will occur.

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.





AMPERAGE BASIC UNIT MORE THANBASE UNIT

MORE THANBASE UNIT

Symbol K MPronounced 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.

RESISTANCE FACTORS



RESISTANCE FACTORSVarious factors can affect the resistance.

These include:

LENGTH of the conductor. The longer the conductor, thehigher the resistance.

DIAMETER of 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. Anydamage will increase resistance.

TYPE of MATERIAL used. Various materials have a widerange of resistances.










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.




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).




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

Alternating Current (AC) Electron flowalternates and flows in both directions (back and

forth).

DYNAMIC ELECTRICITY is electricity that is in

motion. Voltage potential WITH electron flow.Two types of Dynamic electricity exist:







DIRECT CURRENT (DC)Electricity with electrons flowing in only one direction

is called Direct Current or DC.


The Direct Current is known as DC . It Flows

between cathode and anode.

The amplitude of the DC is constant and it isindependent of time

DC is having fixed polarity

anode

cathode




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.


Electrical Fundamentalsf



Electrical Fundamentals 36 of 36

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 DC

electricity.

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