GCSE Physics (AQA)

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Dynamo

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Magnetism and electromagnetism Induced potential, transformers and the National Grid

Dynamo

9:46 Applying the Generator Effect
Spec 4.7.3.2
Previous Potential Difference from an Alternator Next Microphones
  • A dynamo is a simple electrical generator that produces direct current.
  • General setup includes two magnetic poles with a magnetic field between them and a rectangular conducting coil.
  • A split ring communicator connects the coil to wires leading to a circuit while allowing coil rotation.
  • The coil is rotated externally to convert kinetic energy into electrical energy by inducing a current.
  • The generator effect induces a potential difference and current through a conductor moving through a magnetic field.
  • Dynamos produce direct current due to the split ring communicator keeping the current direction consistent.
  • Alternators, in contrast, use two slip rings and produce alternating current by reversing the output current as the coil rotates.
  • The main difference between dynamos and alternators is how they connect the coil to a circuit, affecting the current type.
  • Dynamos keep the output current direction the same, while alternators reverse it.
  • Potential difference graphs show dynamos have a bouncing pattern above the x-axis, while alternators' graphs go above and below the x-axis.
  • Dynamos are used in devices like bicycle lamps and hand-crank flashlights or radios, replacing batteries with direct current generation.
  • Devices powered by batteries use direct currents, while those powered by mains electricity use alternating currents.

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