A voltage amplifier intended for amplifying a low-level input signal. The output is the input to another amplifier with a higher input level. For example, if the second amplifier needs a 500-mV signal to produce the desired power output and one has a microphone with a maximum output of 10 mV, one would use a preamplifier with a gain of 50 to achieve the desired power output. The term preamplifier is not precise; it has been applied to the portion of an amplifier preceding the power output stage and is not an additional system component. The term can also apply to a radio-frequency amplifier to amplify weak signals. The output is the radio receiver input.