Abstract: A peak detector circuit which provides a direct current output voltage proportional to the peak to peak amplitude of an input signal is disclosed. The peak detector is capable of operating with a variety of input signal waveforms. The utilization of an attenuator network and negative feedback techniques permit automatic and accurate operation over a wide dynamic range of input signal amplitudes. Frequency compensation of the attenuator network is provided to permit operation with input pulses having fast rise times and/or fast fall times. The inherent error due to diode forward conduction voltage is eliminated by the use of a DC restorer network which truly clamps the input signal to ground.