A common question in Gamsat is to estimate the current flowing in a portion of an electrical circuit.

The video below (not embeddable) is a good introduction to parallel and serial circuits

http://www.youtube.com/watch?v=E8AZBR8Zz04

Current = Voltage / Resistance

To calculate the current flowing across each globe, for each circuit:

1. Calculate the total resistance by reducing the circuit using ohms law.
2. Resistors in series will all have the same current flowing through them.
3. Resistor in parallel will have a portion of the current flowing through them, so if there are 3 resistors in parallel and they are all the same then each will have 1/3 of the total current flowing through it.