Microphone: Difference between revisions
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'''Capacitance''' - when sound hits the diaphragm it varies the gap and hence the capacitance. As the microphone needs to be polarised (i.e. have a fixed voltage applied across it), varying the capacitance also varies the voltage and therefore gives a true representation of the sound at the output. | '''Capacitance''' - when sound hits the diaphragm it varies the gap and hence the capacitance. As the microphone needs to be polarised (i.e. have a fixed voltage applied across it), varying the capacitance also varies the voltage and therefore gives a true representation of the sound at the output. | ||
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Revision as of 15:24, 1 June 2015
Microphones convert sound energy into electrical energy. There are a number of types :-
Moving coil - similar in construction to a loudspeaker but working in reverse. The sound vibrates the diaphragm which in turn moves the coil and induces an emf into it.
Crystal or piezo - sounds hitting the piezo material causes minute currents to flow.
Capacitance - when sound hits the diaphragm it varies the gap and hence the capacitance. As the microphone needs to be polarised (i.e. have a fixed voltage applied across it), varying the capacitance also varies the voltage and therefore gives a true representation of the sound at the output.