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Dynamo and alternator
Intermediate
Generating electricity using rotation.
A dynamo outputs DC using a commutator; an alternator gives AC using slip rings and is more efficient. Car alternators charge the battery.
Bicycle dynamo lamps.
Output rises with speed.
In more detail
A dynamo produces direct current using a commutator, while an alternator produces alternating current using slip rings. Both use rotating coils or magnets to induce emf.
Real-world uses
- Car alternators charge batteries and power the electrical system.
- Early power systems used dynamos for DC supply.
- Bicycle dynamos and car alternators use rotation and magnetic fields to produce electricity.
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Frequently asked questions
Why do alternators use rectifiers?
They produce AC, which is rectified to DC for battery charging.
What is the difference in the output?
Dynamos give DC through a commutator, while alternators give AC through slip rings.
What is the difference between a dynamo and an alternator?
A dynamo produces DC through a commutator, while an alternator produces AC, which is then rectified if needed.
Related topics in Magnetism & Induction
Transformer · Transformer losses · AC generator · Back emf in a motor · LR circuit growth and decay · Maxwell's displacement current