This circuit is from a 1968s Motorola documentation. The load can range from 10 to 100ohm and the transistor supports a modern equivalent such as 2N2222 or BD135.
The circuit shown is a documentation on 80's tunnel diodes. The frequency depends on the delay line...
This circuit generates excellent sinusoidal signals and has the frequency adjusted by VR1 which is...
This circuit was adapted from an Italian publication that no longer exists. This is “Onda Quadra”...