We found this circuit in a 1965 Electronic Design. The transistors are from the era, and modern equivalents can be tried out.
One touch on S1 and the circuit turns on. With a tap on S2 it turns off. This is the purpose of...
Found in a magazine 73 for radio amateurs from the 90's, this transmitter sends location signals in...
This simple 3-transistor radio with earphone was found in a 1967 documentation. The circuit uses...