1.02 Basic Circuit.
What happens when the circuit is switched on? (i.e. when the switch is closed.)
- Electrons begin to flow around the circuit. They travel from the negative terminal of the battery to the positive terminal. To do this they
pass through the wires, the switch contacts and the filament of the bulb in the circuit. When they arrive at the positive terminal of the battery,
a chemical reaction, causes the electrons to be transferred through the battery, back to the negative terminal. This process keeps current flowing
through the circuit,(until the battery is discharged, i.e., when all of the chemical energy is used up and the chemical reactions stop.)
- The electrons move around the circuit fairly slowly, typically about 1mm per sec (1mms-1).
- Each electron carries a small packet of electrical charge. (A particle which possesses electrical charge is called a
- Electrical current is a measure of the rate at which charge flows around a circuit.