Condenser Microphone Definition

The condenser microphone

is a very simple mechanical system, simply a thin, stretched conductive diaphragm held close to a metal disk called the back plate. This arrangement creates a capacitor, with the back plate receiving its electric charge from an external power source (phantom power). When sound strikes the diaphragm, it vibrates slightly in response to the waveform or whose capacitance changes to the rhythm of the soundwaves that hit the diaphragm. This causes the capacitance to change, which causes the output voltage to vary. This voltage variation is the signal output of the microphone. Phantom power is needed to operate the condenser microphone, either 24 or 48 volts which means that a condenser mic requires at least one additional piece of equipment, a " pre" or preamp.
Most common are large disk studio condenser microphones, which are side address(speak into the side of the mic) and cardioid (directional). The directional nature of condenser microphones makes them popular for studio and voice over work because ambient noise from the back is reduced. Such noise might be street noise or the voice actors voice being reflected from a wall.
There are preamps that provide phantom power and at the same time convert the microphones analog signal to digital for direct connection to a computer by USB or IOS firewire connection. A condenser microphone definition has to mention some cheaper microphones that are sold as condenser microphones but are of a different type known as eletret. They use a permanently charged plate and do not reproduce sound with the quality of top condensers.