(notes taken from the CGP revision guides)
- Electric current is a flow of charge round a circuit.
- In an electrical circuit the components and wires are full of charges that can move.
- Circuit wires are usually metal with a plastic cover. Electric charge flows in a metal conductor because there are lots of electrons that are free to move around. Current can't flow in an insulator because the electrons are fixed.
- In a complete circuit, that battery pushes charge through the wires. The charge flows all the way round the circuit and back to the battery - it's not used up and doesn't disappear.
- Current depends on voltage and resistance.
- Current will only flow through a component if there's a voltage across that component.
- Voltage is the driving force that pushes the crrent round. Its units are volts, V.
- Resistance is anything in the…