GCSE Physics (AQA)
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Alternating & Direct Potential Differences
- Direct potential difference remains in one direction, causing a direct current (DC).
- Direct current (DC) is defined as a current where charge carriers flow in the same direction around a circuit.
- Electrons in a direct current travel in the same direction.
- Alternating potential difference switches direction, causing the current to switch direction, known as alternating current (AC).
- Alternating current (AC) is defined as a current where charge periodically changes direction in a circuit.
- In AC, charge carriers are pushed back and forth, transferring energy to each other.
- Direct potential differences are provided by power sources like cells or batteries, which have positive and negative terminals.
- Examples of DC sources include cells, batteries, and dynamos, but exams typically require only cells and batteries to be stated.
- Alternating potential differences are provided by power sources such as AC generators.
- AC generators convert kinetic energy into electrical energy and are used in the national grid.
- Only single science students need to know the details of how the AC generator works for exams.
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