Alternators, dynamos and microphones
Turning a coil in a field gives a.c. through slip rings or d.c. through a commutator; reading peak, period and frequency off the output graph; and how a moving-coil microphone works.
You will be able to
- Tell an alternator from a dynamo and their output graphs apart
- Read the peak p.d. and period from a graph and work out the frequency
- Explain how a moving-coil microphone turns sound into a signal
20 minutes, 8 exam-style questions.