This is one of the first radios with an integrated circuit. The circuit is from a Radio Electronics from November 1969. The circuit is powered by a 9 V battery.
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...