Networks, Time and Fields
Series & Parallel Networks
13 minStudent plan
How resistances combine, why parallel always lowers resistance, and how to reduce a messy network to a single number.
After this lesson you can
- Combine resistors in series and in parallel
- Predict which components share a current and which share a voltage
- Work out a divider's output before you build it
Series: one path
Components in series sit end to end on a single path. There is nowhere else for charge to go, so the same current flows through every one of them.
Resistances in series simply add: R_total = R1 + R2 + R3. Two 220 Ω resistors in series behave as 440 Ω.
The voltages, by contrast, divide. The supply voltage is shared out in proportion to resistance, and the shares always sum back to the supply. That is Kirchhoff's voltage law arriving early, and it is the whole basis of the potential divider: the bigger resistor takes the bigger share of the voltage.
In the full lesson
- Series: one path
- Parallel: multiple paths
- Reducing a network
This lesson comes with the Student plan. The first module of Physics for Engineers is free.