Series and parallel circuit rules

What is Series and parallel circuit rules?

The two conservation rules that govern every circuit: charge is conserved, so the current is the same everywhere in a series circuit and the current into a junction equals the current out of it; energy is conserved, so the supply p.d. equals the sum of the p.d.s across series components while every parallel branch has the same p.d. across it. Combined resistance is R = R1 + R2 + R3 in series and R = R1R2/(R1 + R2) for two resistors in parallel.

This definition is part of the Electricity and Magnetism chapter in Cambridge O Level Physics.

Concepts related to Series and parallel circuit rules

• junction rule
• combined resistance
• potential divider
• ohm's law