IEB electric circuits grade 12 summary

Grade 12 Physical Science Electromagnetism

Current Electricity Summary

Resistors in Series Resistors in Parallel
Only one path for current More than one path for current


V4 V4

A5 V4
A3 A1 A4
A3
R3
V3

A2 R2 A2
R1 R2 R3
V3 V2
V1 V2
R1 A1

V1

A current divider.
Current strength is the same The current is the same anywhere in
anywhere in a series circuit the series part of the circuit, but splits
when it reaches parallel branches.
A1 = A2 = A 3 Lower resistance = higher current.
Atotal = A4 = A5
A1 + A2 + A3 = Atotal
A potential divider. Potential is the same across all
Potential divides in the same ratio as branches of a parallel network.
the resistors
emf = V4 = V1 + V2 + V3 emf = V4 = V1 = V2 = V3
1 1 1 1
Rtot = R1 + R2 + R3 = + +
𝑅𝑡𝑜𝑡 𝑅1 𝑅2 𝑅3

Q W V
I = V = R =
t Q I

R = resistance ()
W = VIt W = I2 R t W = V2 t
V = potential difference (V)
R
I = current strength (A)
P = VI P = I2R P = V2
Q = charge (C)
R
W = Work/heat/energy (J)
t = time (s)
P = power (W)
1