E&M > Magnetic Fields and Forces > Forces on Current-Carrying Coils DCS# 5H25.10 v2
PLASTIC CUP MICROPHONE/SPEAKER
 
APPARATUS
plastic cup speaker
 		202-19-B6
audio transformer
 		214-01-D
radio
 		202-09-E
amplifier/speaker
 		202-20-B2

DESCRIPTION
The cup serves as a diaphragm. There is a coil glued to the bottom of the cup and a magnet resting on the base beneath it. When functioning as a speaker, the coil is connected to the output of the radio or other sound source. For the microphone, connect the coil to an audio transformer and to the speaker/amplifier.