Amplification based on the noise-induced negative differential resistance in a Zener diode

A voltage biased Zener diode always exhibits positive differential resistance and thus cannot be used as an element to provide amplification of a signal. We show how to induce negative differential resistance in the reverse bias regime of a 12 V Zener diode simply by adding a series resistor providing noise feedback. We use this to build a voltage amplifier in the audio frequency range, which we characterize by providing bandwidth, gain, power consumption, gain compression, and output noise spectral density.