What is the difference between ac and dc bitesize

All the circuits you have studied so far are d. A current that continuously changes its direction, going back and forth around a circuit. Two graphs showing the variation of current with time for alternating current and direct current. Direct Current vs.

Alternating Current Table. If you are asked to explain the difference between alternating and direct current, sketching and labelling the graphs shown above can earn you full marks. A direct current d. An alternating current a. On an oscilloscope, direct current and alternating current are represented in the following way: Two graphs showing the variation of current with time for alternating current and direct current. The following table summarises the differences between d.

Key Concepts of Physics 1. Conservation of Energy 3. Waves 4. Radioactivity 6. Astronomy 7. Energy — Forces Doing Work 8. Some bike lights use a type of dc generator called a dynamo to run the lamps while the wheels are turning.

In a dynamo, a split ring commutator changes the coil connections every half turn. As the induced potential difference is about to change direction, the connections are reversed.

This means that the current to the external circuit always flows in the same direction. The output of a rotating dynamo can be shown on a potential difference-time graph. The graph shows a sine curve that stays in the same direction all the time. The maximum potential difference or current can be increased by: The diagram shows four different positions of the coil in a dynamo, and the corresponding potential difference produced. The coil is moving parallel to the direction of the magnetic field, so no potential difference is induced.

Here, the induced potential difference travels in the same direction as at B.