electrical circuit behavior

8/14/2019 Electrical Circuit Behavior

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Electrical Circuit Behavior

Section III

In this Section we will introduce the following information:

Theory behind Circuit Behavior Construction of all circuits Series Circuit Behavior

Parallel Circuit Behavior Series/ Parallel Circuit Behavior Introduction to Meter Application in Circuits


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Series Circuits

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Battery

fuse

Load 1

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Load 2

Series Circuit Rules

1. The Resistance Totalwill always be

equal to the sum of all of the loadresistances in the circuit.

2. The total circuit Voltage Dropwillalways be equal to the applied source

voltage.However, each load will havea different voltage drop based on itsindividual resistance value.

3. The Current flowin the the circuit

is the same regardless of where itis measured.

A Series Circuit is considered a Voltage Dividing Circuit


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Series Circuits

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----

Current is the same everywhere

Resistance Total is the sum

of each load resistance

Voltage Drop across the total circuitequals the applied source voltage

Battery

fuse

Load 1

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Load 2

2 Ohms2 Ohms

2 Ohms + 2 Ohms = 4 Ohms Total

RT= The sum of all Resistance


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Series Circuits

6 Volts + 6 Volts = 12 Volt Voltage Drop

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Vdr= Voltage DropVoltage drop equals the applied

source voltage.This is the voltageconsumed or used by the circuitcomponents or resistors.


Resistance Total is the sum of each loadresistance

Voltage Drop across the total circuit equalsthe applied source voltage

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Battery

fuse

Load 1

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Load 2

12 Volts 12 Volts

12 Volts12 Volts

6 Volts6 Volts

12 Volts


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Series Circuits

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Battery

Load 1

4 Ohms

12Volts

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----

It= Intensity TotalThis refers to the total current

(amps) flow through the circuit.


Resistance Total is the sum of each loadresistance

Voltage Drop across the total circuit equals

the applied source voltage

3 Amps

12 Volts 4 Ohms = 3 Amps

Note: When calculating Amps, an ammeteris placed in series with the circuit.

3 Amps


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R1

3 Ohms

12Volts

Amps ?

Volts R1 = ? Amps12 Volts 3 Ohms = 4 Amps

Series Circuits

E

? R

Using Ohms Law calculate the amountof amp flow in the circuit below

E = VoltsR = OhmsI = Amps


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Volts R1 + R2 = ? Amps6 Ohms + 4 Ohms = 10 Ohms

12 volts 10 Ohms = 1.2 Amps

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R1

6 Ohms

12Volts

Amps ?

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R24 Amps

E

? R

Series Circuits

E = Volts

R = OhmsI = Amps

Using Ohms Law calculate the amountof amp flow in the circuit below


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R1

? Ohms

12 Volts

10 Amps

Volts Amps = Resistance

12 Volts 1.2 Amps = 10 OhmsE

I ?

Series Circuits

E = Volts

R = OhmsI = Amps

Using Ohms Law calculate the amountof resistance in the circuit below


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Series Circuit Review

Ohms Law can be applied to a series circuit to find unknownvalues as long as you have at least two of values required towork the formula and, you remember the following rules for a

seriescircuit.

1. Since there is only one path for current to flow through,current througheach load(resistance) is the same regardless of the number of loads in

the circuit or where the current is measured in the circuit.

2. The total resistance in the circuit will equal to the sum of the individualload resistances in the circuit.

3. The voltage drop at each load will vary depending on its resistance,however, the total voltage drop will be equal to the applied sourcevoltage.Source voltage is divided completely by all the loads, thereforea Series Circuit is referred to as a Voltage Dividing Circuit.


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Parallel Circuits

Parallel CircuitA parallel circuit has two or more pathsfor current to flow through. Theamount of current through eachbranch is determined by the loadresistance of each branch. If the circuitis broken after a load, only that loadwill cease to operate.


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w w 12

volts4 4

R1 R2

Parallel Circuits

12volts

12volts

Parallel Circuit Rules

1.The source voltageand the voltageapplied to or measured across each loadresistance is the same.

2.The current through each load is

determined by its resistance.

3. The resistance totalof the circuit willalways be less than the lowest resistancein the circuit.

4. The total currentin the circuit will beequal to the sum of the branch currentsthrough each individual load.

A Parallel Circuit is considered a Current Dividing Circuit


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Source Voltage(Sv) is the same thruboth loads.

Resistance Total(Rt) will be less than

lowest value of individual resistor.

The Total Current (It) in the circuit willequal the sum of the branch current flow

R2

I = V / R

12 v/ 2 = 6 amps

E

? R

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w w w w

12volts

4

2

R1 R2

Parallel Circuits

R1

I = V / R

12 v/ 4 =3 amps

E= Electromotive Force (EMF) or VoltsR= Resistance or Ohms ( )

I = Intensity of Current (quantity), (A),or amps (short for amperage)

Load resistance determines

current through each load

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Rt = (R1 X R2) / (R1 + R2)

(4 X 2)=8 / (4+2)=6

8 /6 = 1.33 ohms

Parallel Circuits

E

I R

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w w w w

4

2

R1 R212

volts

Source Voltage(Sv) is the same thru

both loads.

The Total Current (It) in the circuit willequal the sum of the branch current flow.

NOTE: Individual resistor value does not

matter in a parallel circuit, only whencalculating current flow thru one load usingohms law does it matter.

E= Electromotive Force (EMF) or Volts

R= Resistance or Ohms ( )I = Intensity of Current (quantity), (A ),

or amps (short for amperage)

Total Circuit Resistance willalways be less than the

lowest individual resistancein the circuit.

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Source voltage and the voltage applied

to each load is the same

Load Resistance determines currentthough each load

Total circuit resistance less than lowestload resistance

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w w w w

4

2

R1 R212

volts

3 amps 6 amps

Parallel Circuits

Total circuit current equals

the sum of the branchcurrents

It = the sum of the individual branches3+6=9 amps

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Parallel Circuit Review

Ohms Law can be applied to a series circuit to find unknownvalues as long as you have at least two of values required towork the formula and, you remember the following rules for

a parallel circuit.1. The source voltage and the voltage applied to a load (resistance) is

exactly the same and cannot vary.

2. The current through each load is determined by the resistance value ofeach resistor.

3. The resistance total of the circuit will always be less than the lowestresistors value.

4. The total current flow in the circuit will be equal to the sum of the

branch currents through each resistor.The total current in the circuitis divided between the loads, therefore, a parallel circuit is sometimesreferred to as a Current Dividing Circuit.

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Series Parallel Circuits

Series Parallel Circuit

As the name implies, the series-parallel isa combination of of both types of circuits.

One or more of the loads is in series, whilethe others are in parallel.

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ww

ww

ww

ww12

volts

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Dimmer

Series-Parallel Circuit Rules

1. The Resistance Total of the circuit isequal to the sum of the parallel resistanceplus the series resistance.

2. The Current in the series portion of thecircuit is equal to the sum of the branchcurrents.

3. The VoltageDrop across the series

resistance will reduce the voltage suppliedto the parallel branches.

12 volts 6 volts 6 volts

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= ------------

= ---------------

= ---------

(R X R ) 2 3

(6 X 3 )

Rtp

Rtp

R

tp

Rtp

(R + R ) 2 3

18 Ohms

9 Ohms

= 2 Ohms

Circuit Total Rt 4 Ohms


(6 +3 )

Rtp=

+ Rts

Rt =+2 2 =

4

ww

ww

ww

ww

12

volts

WWWW

Dimmer

Series Resistance

R1Set at

2 Ohms

Parallel

ResistanceR 2 6

Parallel

ResistanceR 3 3

The Resistance Total of the circuitis equal to the sum of the parallelresistance plus the series resistance.

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Current in the the series portion ofthe circuit is equal to the sum of

the branch currents.


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ww

ww

ww

12volts

WWWW

Dimmer

Series Resistance

R1Set at

2 Ohms

Parallel

ResistanceR 2 6

Parallel

ResistanceR 3 3 It

It

=

=

=

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------

Rt

12Volts

4 Ohms

3 Amps

Sv

It

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6 Volts

3 Amps


=

=

=

R ItX

X2 Ohms

6 Volts

Vdr

Vdr

Vdr

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wwww

12volts

WWWW

Dimmer

Series Resistance

R1Set at

2 Ohms

ParallelResistance

R 2 6ParallelResistance

R 3 3

The Voltage Drop across the seriesresistance will reduce the voltagesupplied to the parallel branches

Voltage Drop

6 volts 6 volts

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Series Parallel Circuits Review

Ohms Law can be applied to a series-parallel circuit to find

unknown values as long as you have at least two of valuesrequired to work the formula and, you remember the followingrules for a parallel circuit.

1. The Resistance Total of the circuit is equal to the sum of the parallelresistance plus the series resistance.

2. The current in the series portion of the circuit is equal to the sumof the branch currents.

3. The Voltage Drop across the series resistance will reduce the voltage

supplied to the parallel branches.

electrical circuit behavior

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