This high sensitivity receiver of 30 nW was found in documentation from the 1980s. Integrated circuits are from that time.
Yes, tunnel diodes can also be used in voltage regulators, as shown in this circuit from a Radio...
The gain of this circuit at 1 kHz [and 40 dB falling rapidly when the frequency deviates from this...
A frequency of up to a few kilohertz can be obtained with this oscillator. The frequency is given...