BASICS OF ELECTRICITY 1 WHAT IS ELECTRICITY? 1) Generating electricity + - Hydrogen atom + + - -...

BASICS OF ELECTRICITYBASICS OF ELECTRICITY

1 WHAT IS ELECTRICITY?1) Generating electricity

+-

Hydrogen atom

+ +

-

-

Helium

+ +

-

-

-

Lithium

Atomic nucleus

Electron

Atomic nucleus

Proton

Neutron


2) Frictional electricity

(1) When two different objects are rubbed together, electricity is produced.(2) Frictional electricity is positive or negative.(3) Similarly charged bodies repel each other.(4) Oppositely charged bodies attract each other.

cak sol sumber HQS


1 CURRENT, VOLTAGE, RESISTANCE1) Current(1) What is Current?

Electric cableFree electron

Electron move.

Neutralized Supplied from B

AA BB AA BB


(2) Current unit

1 Second1 Ampere 1 Coulomb=

< Units >1 ampere = 1000 milliamperes1 milliampere = 1000 microamperes

< Symbols >Ampere (A)Milliampere (mA)Microampere (µA)


2) Voltage

Waterpressure

Voltage

Electron flow

Current

No water pressure Voltage is zero


3) ResistanceGenerator

Current

Load resistance

Cable internal resistance


)(µ Microohm)( Ohm)(k Kiloohm)(M Megaohm

> Symbols <ohm 10 = ohm 1/1000000 = microohm 1

ohm 1ohms 10 = ohms 1000 = kiloohm 1

ohms 10 = ohms 1000000 = megaohm 1> Units <

6-

3

6


4) Ohm's Law

132


)ohms(cetansisRe)volt(Voltage

=)amper(Current

) ( R x (A) I=(V) E

(A) I(V) E

=) ( R

) ( R(V) E

=(A) I

: Current: Voltage: Resistance

IER

R•I=E

IE

=RRE

=I


3 ELECTRIC CIRCUIT (APPLYING OHM'S LAW)1) Basic circuit

Switch FuseLamp

+ - 12 V 6

I = ?

(1) When voltage and current are known and resistance is determinedBASICS OF ELECTRICITYBASICS OF ELECTRICITY

When a resistance was applied to a voltage of 24V, a current of8A was produced. What was the resistance value?

24 V

I = 8 A

R = ?

From Ohm's Law

I = 8 (A)E = 24 (V)

IE

=R

) (3=824

=R

(2) When resistance and current are known and voltage is determinedBASICS OF ELECTRICITYBASICS OF ELECTRICITY

How many volts is required to conduct a current of 2A througha resistance of 50

100 V

I = 2 A

R = 50

From Ohm's Law

R = 50I = 2 (A)

E = I x R

E = 2 x 50 = 100 (V)


2) Series circuit

14


R1 R2 R3

E

E1 E2 E3

Total voltage E = E1 + E2 + E3

= I•R1 + I•R2 + I•R3

= I (R1 + R2 + R3)

Combined resistance E = E1 + E2 + E3


Let's obtain the values of the combined resistance and the current.

12 V

6 4 2

)A(1=1212

=RE

=I

R = R1 + R2 + R3

6 + 4 + 2 = 12


3) Parallel circuit

R1

R2

E

I2

I1

I

)R1

+R1

( E=RE

+RE

2121I = I1 + I2 =Total current


21 R1

+R1

1=R

21 R1

+R1

=R1

Combinedresistance ) (R

)V(E=)A(I

) (R1

x )V(E=

Ohms’ Low


What is the combined resistance value in the figure below?

20=R1

30=R2

60=R3

601

+301

+201

1=

R1

+R1

+R1

1=R

321

[ ]10=6

60=

6061

=

601

+602

+603

1=


4 SOLENOID PRINCIPLE1) Current and magnetic field

- +

S

N


Paper

-+ -+N

SN

N

N

S

SS


Current

Current

Right-handed screw rule


2) Magnetic fields created by a coil

Magnetic force lines

Current


N pole S pole


Current

Right hand

Current flow directionRight-hand grip Rule

N S


Iron core

Coil

Iron bar


5 STARTER WORKING PRINCIPLE1) Electromagnetic force (Fleming's Left-hand rule)

Conducting wire and Current direction

Direction of magnetic force line is the same, so electromagnetic force is strong.

Direction of magnetic force line is the opposite, so electromagnetic force is weak.

Expulsion force


Fleming's left-hand rule

Force direction

Magnetic force line direction

Current direction

Current (A)

Magnetic field (A/M)

Force (N)

N to S

+ to -

N S

+

-


Magnet

CoilBrush

Power supply

Commutator

+ -


Force

Current

Magneticforce line

Magneticforce line

Force

Current Force

Current

Magneticforce line

Magneticforce line

Force

Current

Current flow direction isreversed by commutator.


6 GENERATOR WORKING PRINCIPLE1) Electromagnetic induction (Fleming's right-hand rule)

Ammeter

Electromotive force is produced when the conductor is moved up and down

+

-

Electromotive force (V)

= magnetic flux x conductor length (m) x conductor moving speed (m/s))m/Wb( 2

Fleming's right-hand ruleBASICS OF ELECTRICITYBASICS OF ELECTRICITY

Conductor direction


Electromotive force direction

N to S

+ to -

Fleming's left-hand rule

Current

Force

Magneticforce line

+

-

NS


2) Current Generator Working Principle

B1 B2

C1C2

a

b

c

d


3) Alternating current generating principle

B1

B2S1

S2

a

b c

d ad

c b


7 BATTERY PRINCIPLE1) Battery purpose

Connected in parallel


2) Battery structure and function

Terminal

LidCell plug

Connector

SeparatorGlass mat

Positive plateNegative plate

Battery jar

Glass mat

Positive plate

Pole

Negative plate

SeparatorPole


Pb + 2H2SO4 +PbO2 PbSO4 + 2H2O + PbSO4

Positive pole platesNegative pole plates

++

++

--

--

++++

Hydrogen ion +Lead ion +

Negative pole Positive poleCurrent

Electron


+-

Larger terminal is positive


3) In-service maintenance

020406080

100120140160180200220240

1.240 1.250 1.260 1.270 1.280 1.290 1.300 1.310 1.320

Diluted sulfuric acid(Specific gravity : 1.400) Purified water

Rep

lace

able

qua

ntity

(CC

)(p

er 1

lite

r of e

lect

roly

te)

Battery electricity specific gravity (20 degrees)

(1) Adjusting electrolyte level and specific gravity


(2) Measuring electrolyte specific gravity

A

B

Rubber ball

Glass tube

Floating scale

Suction tube


4) Storage cautions


5) Charging(1) Charging type

Supplementary chargingInitial charging


(2) Charging methods

Constant-current charging method

Fast charging method

1

2


(3) Voltage and specific gravity changes during charging

0 2 4 6 8 10 12 14 16 18 20

1.1

1.2

1.3

2.0

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

1.9

Charging time (H)

Term

inal

vol

tage

(V)

Spe

cific

gra

vity

Voltage

Specific gravity


(4) Charging-related cautions

+-

-+

+ +

--

1.5) to 1.2( x current(A) Charging

rate(Ah) Discharge=time(h) Charging


(5) Battery capacity

Unit Ampere-hour (Ah)

Ampere-hour capacity (Ah) = discharge current (A) x discharge time (h)

Watt-hour capacity (Wh) = discharge current (A) x discharge time (h) x mean discharge voltage (V)

(Example)

Discharge: 5 hours

Current: 6A6 (A) x 5 (h) = 30 (Ah)

Voltage: 12V

Battery: 40Ah40 (Ah) x 12 (V) = 480 (Ah)

Ampere-hour capacity (Ah)


100Ah

20 hours at 5 A

5 A

100Ah

10 hours at 10 A

Heat lossChemicalreactions

10 A


8 CIRCUIT TESTER1) Outline

(1) Measurement of alternating or direct-current voltage and current(2) Measurement of resistance(3) Discovery of electric circuit shorts, grounds, and disconnections

2) Structure

Positive side cordterminal

Measuring range

Alternating voltagemeasuring range

Direct-currentvoltage measuringrange

Negative sidemeasuring cord

Resistance measuringscale

0 point adjusting screw

0 point adjusting knob

Negative sideterminal

Direct currentmeasuring range

Positive sidemeasuring cord


3) Measuring voltage

+- + - + - +- +

Battery

Bat

tery

Household-usewall outlet

OK

Direct current Alternating current

-

Alternating voltagemeasuring range

0 point adjusting screwDirect-current voltagemeasuring range


Reading the tester


4) Measuring current

0 point adjusting screw

Current up to 250mA

Current up to 20A

Bat

tery

Bat

tery-+

-+

+

-

+

-

Tester

Tester


Reading the tester


5) Measuring resistance

0 point adjusting knob

Bat

tery

+ -Tester

OFF


Reading the tester


8 ELECTRIC COMPONENTS


1) Resistors

Resistor

Fixed resistor

Symbol: RWPower type covered wire wound resistor

Variable resistor

Carbon film fixed resistor

Fixed body resistor

Insulated carbon film process resistor

Symbol: RD

Symbol: RC

Symbol: RF

H RD 1/2 P X G150k

Ratedpower(W)1/81/41/21

Carbonfilmfixedresistor

H whenfrequencyis high

XYZAB

10±:K5±:J2±:G1±:F

5.0±:D[%]

][M][k][

P

L

Serviceobjective Type Shape

Resistancevalueallowance

NormalresistancevalueProperties


Symbols inscribed on resistors


Fixed body resistor color code

1st color band 2nd color band 4th color bandBlack 0 0 x10 0 -Brown 1 1 x10 1 -Red 2 2 x10 2 -

Orange 3 3 x10 3 -Yellow 4 4 x10 4 -Green 5 5 x10 5 -Blue 6 6 x10 6 -

Purple 7 7 -Gray 8 8 -White 9 9 -Gold - - x10 -1 5%Silver - - x10 -2 10%

No color - - 20%

Color

--

-

3rd color band

Resistance valueallowance2-digit number

-

MultiplierResistance value

4th color3rd color2nd color1st color


10% ± 10 x 0 2 2

10%± :allowance value Resistance2,000 :value Resistance


Fixed body resistor color code

1st color band 2nd color band 3rd color band 5th color bandBlack 0 0 0 x10 0 0,5%Brown 1 1 1 x10 1 1%Red 2 2 2 x10 2 2%

Orange 3 3 3 x10 3 -Yellow 4 4 4 x10 4 -Green 5 5 5 x10 5 -Blue 6 6 6 x10 6 -

Purple 7 7 7 -Gray 8 8 8 -White 9 9 9 -Gold - - - x10 -1 5%Silver - - - x10 -2 10%

No color - - - 20%

Resistance valueallowance

-

MultiplierResistance value

3-digit numberColor

--

-

4th color band

5th color4th color3rd color2nd color1st color


1% 10 x 2 0 2 2

10% :allowance valueResistance22020.200 : valueResistance

k


2) Fuses

Capacity 10% current 135% current 150% current5A Mast fuse Fuses within 60 min. Fuses within 15 sec.10A Mast fuse Fuses within 60 min. Fuses within 15 sec.15A Mast fuse Fuses within 60 min. Fuses within 15 sec.20A Mast fuse Fuses within 60 min. Fuses within 15 sec.25A Mast fuse Fuses within 60 min. Fuses within 15 sec.30A Mast fuse Fuses within 60 min. Fuses within 30 sec.

Housing Fusible strip

Terminal

Fusible strip

Terminal

Blade type Glass type


(Reference)Electric wire allowable current

Nomination(cross-sectional

area mm)Strand diameter mm Number of strands Outer diameter mm Allowable current A

0.5 0.32 7 2.2 90.85 0.32 11 2.4 121.25 0.32 16 2.7 15

2 0.32 26 3.1 203 0.32 41 3.8 275 0.32 65 4.6 378 0.45 50 5.5 4715 0.45 84 7.0 5920 0.8 41 8.2 8430 0.8 70 10.8 12040 0.8 85 11.4 13550 0.8 108 13.0 160


3) Diodes

Diodes

General distribution diode

Low voltage diode (Zener diode)

Light-emitting diode

Photo diode

1 General distribution diode

BASICS OF ELECTRICITYBASICS OF ELECTRICITY2 Zener diode

Properties of general rectifier diodes Zener diode properties

0 1 2

-5

Forw

ard

dire

ctio

ncu

rren

t (A

)R

ever

se d

irect

ion

curr

ent (

mA

)

Forward directionvoltage (V)

Reverse directionvoltage (V)

5V Zener diode

-100

50

50

0 1

Forw

ard

dire

ctio

ncu

rren

t (A

)

Rev

erse

dire

ctio

ncu

rren

t (m

A)

Forward directionvoltage (V)

Reverse directionvoltage (V)

Germanium diodeSilicon diode

BASICS OF ELECTRICITYBASICS OF ELECTRICITY3 Light-emitting diode

Light

Hole Electron

P N


4) Transistors

N

P

N

C

E

BP

N

P

C

E

B

NPN type PNP type

EmitterBase

CollectorEmitterBase

Collector

Emitterprotrusion

Straight line


Designation of Symbols

2 S C 154 A

S

One-digitnumber

Letter ofalphabet

Meaning ofsemiconductor

parts

Twe-digitor largernumber

Letter ofalphabet

(Number of rectifierJunctions)

(Semiconductor S) (ApplicationIndication)

(Registrationnumber)

(Improvementnumber)

PNP high frequency usePNP low frequency useNPN high frequency useNPN low frequency useThyristor

ABCDF

……………

Photo transistorDiode3-pole diode4-pole diode

…………

0124


5) ThermistorsR

esis

tanc

e

Temperature

Negativecharacteristicthermistor

Positivecharacteristicthermistor

Case

Thermistor

Terminal


(+) (-)

++++

----

A B

Insulator

Condenser(Capacitors)

Variable condenser

Fixed condenser

Air condenser (variable condenser)

Mica condenser

Aluminum electrolytic condenser (AI condenser)Tantalum condenser (Ta condenser)Barium titanate condenserTitanium dioxide porcelain condenserMetallized paper condenser (MP condenser)Plastic film condenserPaper condenser


Tubular paper condenser Porcelain condenser

Titanium condenser

Electrolytic condenser

Mica condenser

Variable air condenser

Oil-impregnatedcondenser

Condenser type

BASICS OF ELECTRICITY 1 WHAT IS ELECTRICITY? 1) Generating electricity + - Hydrogen atom + + - -...

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Transcript of BASICS OF ELECTRICITY 1 WHAT IS ELECTRICITY? 1) Generating electricity + - Hydrogen atom + + - -...