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GCSE Physics · key term
A device that converts variations in sound pressure into a corresponding electrical signal.
Used by OCR
Specification P4.2j · Paper 1 (Foundation), Paper 3 (Higher)
Revise: Microphones and speakersAt one moment the air pressure at the microphone is slightly higher; a moment later it is slightly lower. A microphone must turn these rapid pressure variations into matching variations in an electrical circuit.
State the energy and signal conversion clearly: a microphone converts sound pressure variations into electrical current variations; a loudspeaker or headphones perform the reverse conversion.
For a dynamic microphone, write about electromagnetic induction: the coil moves through a magnetic field and an alternating potential difference is induced. Do not describe this as the motor effect.
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