17.4 - AC & DC Current
Direct current
- In direct current, the charges move in one direction only, so the current always flows the same way around the circuit.
- It's produced by a direct potential difference - a p.d. that stays positive, or stays negative, rather than switching between the two.
- Cells and batteries supply direct current.
Alternating current
- In alternating current, the current is constantly changing direction, flowing back and forth around the circuit.
- It's produced by an alternating potential difference, in which the positive and negative ends keep swapping over.
- The mains electricity supplied to homes is an alternating current.
TermDefinition
Direct currentA current where the charges move in one direction only, flowing the same way around the circuit.
Direct potential differenceA potential difference that stays positive or stays negative, rather than switching between the two.
Alternating currentA current that is constantly changing direction, flowing back and forth around the circuit.
Alternating potential differenceA potential difference in which the positive and negative ends keep swapping over.