# Parallel circuits

In parallel circuits, electrical are connected alongside one another, forming extra loops.

## Circuit rules

An will not pass through every component on its way round the circuit. If one of the bulbs is broken then will still be able to flow round the circuit through the other loop. If one bulb goes out, the other will stay on.

### Current in parallel

Since there are different loops, the current will split as it leaves the cell and pass through one or other of the loops. An placed in different parts of the circuit will show how the current splits:

$I_{1} = I_{2}+I_{4} = I_{3}$

This is when:

• current (I) is measured in amps (A)

### Potential difference in parallel

Since has to be conserved, the energy transferred around the circuit by the electrons is the same whichever path the electrons follow. Since is used to measure changes in energy, the potential difference supplied is equal to the potential differences across each of the parallel components:

$V_{s} = V_{1} = V_{2}$

This is when:

• potential difference (V) is measured in volts (V)

### Resistance in parallel

If are connected the supply current is divided between them. The overall is reduced as the current may follow multiple paths.

In parallel circuits:
• the total current supplied is split between the components on different loops
• potential difference is the same across each loop
• the total resistance of the circuit is reduced as the current can follow multiple paths