A
microphone design where a
wire coil (the
voice coil) is attached to a small
diaphragm such that sound pressure causes the coil to move in a magnetic field, thus creating an electrical
voltage proportional to the sound pressure. Works in almost the exact opposite of a
dynamic loudspeaker where an electrical
voltage is applied to the
voice coil attached to a large
cone (
diaphragm) causing it to move in a magnetic field, thus creating a change in the immediate sound pressure. In fact, under the right circumstances, both elements will operate as the other, i.e., a
dynamic loudspeaker will act as a
microphone and a
dynamic microphone will act as a
loudspeaker -- although not too loud. See
electromagnetic induction.
