Current
Alternating and direct current
An The movement of electrically charged particles, for example, electrons moving through a wire or ions moving through a solution. flows either as a Also called dc. An electric current that flows in one direction only. or as an Also called ac. An electric current that regularly changes its direction and size..
Direct current
On a voltage-time graph this would appear as a straight horizontal line at a constant voltage.
Car batteries, dry cells and solar cells all provide a direct current (dc) that only flows in one direction.
Alternating current
On a voltage-time graph, this would appear as a curve alternating between positive and negative voltages - the positive and negative values indicate the direction of Moving electric charges, eg electrons moving through a metal wire. flow.
Power stations usually provide an alternating current (ac). In the UK, the The electrical supply found in homes, shops, offices and factories. In the UK, the mains supply is 230 V with a frequency of 50 Hz. is generated at a The number of waves produced each second. The unit of frequency is hertz (Hz). of 50 hertz (Hz) and is delivered to houses at about 230 volts (V).