We found this circuit in an English publication from the 60's. The transistors are of germanium of the time and the headphones must be high impedance magnetic.
This basic oscillator with tunnel diode generates a 100 kHz signal with 1 uW output power. The...
This windshield wiper interval switch was found in the April 1990 issue of Radio Electronics...
This circuit is from General Electric from the 80s, using a relay with high current contacts (20...