Circuits

Series Circuits

Current is the same everywhereVoltage gets divided up based on the resistance

Big R = Big V

small R = small V

Parallel Circuits

Current gets divided up amongst the resistorsVoltage stays the same

SERIESPARALLEL

SERIES

Resistors in Series…just add up

321 RRRReq Resistors in Parallel…add the reciprocals

321

1111

RRRReq

= 3

= 2= 4

= 1

= 5 EquivalentResistance

These two resistors in parallel can be calculatedas one resistor

323,2

111

RRR

2

1

4

11

3,2R

R2,3 = 1.33

Req = 3 + 1.33 +1 +5 = 10.33

Find the EquivalentResistance and Currentin the circuit

series= 10

parallel

10

1

10

1

= 5 series = 10

I = V/Req = 40.0V/10 = 4AWhat is the current through the 2.0 resistor?equal resistance…the current divides equally 2A each way

Find the equivalent resistance and currentthrough the 20 and 8 resistors

= 20

= 40

= 20

= 40

I = V/Req = 12V/40 = 0.3 A

I through 8 resistor = .15 A

What if the resistance is not equal in each resistor?

12V 6 2

How much current is going through the 2resistor?Calculate the equivalent resistance…

1/Req = 1/6 + 1/2 = .667

Req = 1.5

Calculate the current in the circuit I = V/Req I = 8A

The 6 resistor has 3x the resistance than the 2, so 3x morecurrent will flow through the 2 resistor… (2 gets ¾, 6 gets ¼)