In fact, the speed is so slow that electrons in an AC circuit hardly move at all since they just pace back and forth a very small amount on each half cycle.

In contrast to alternating current, or AC, which, depending on the supply's frequency, switches direction 50 or 60 times per second, the current in DC circuits flows only in one direction.

Learn about and revise electrical circuits, charge, current, power and resistance with GCSE Bitesize Combined Science.

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