Negative Resistance Oscillator with Homemade Tunnel Diode:
This project may not be very practical but I find it to be a
very exciting experience. When I first heard about tunnel diodes
many years ago, they seemed to me, to be one of the most exotic
devices on earth. It was very exciting to discover that I could
easily make at home, at least in very crude form, an actual
working device that is similar.