Found in a 1967 Electronics World, this oscillator changes its tone when objects move in their environment. The output is made on a low impedance phone.
We found this circuit in a 1997 documentation. Power transistors must have good heat sinks. The...
This old circuit is from the era of analog televisions, serving for technicians to make...
e find this circuit in documentation for radio amateurs of 1974. The unijunction transistor can be...