This old 1967 audio preamp uses germanium transistors. It was found in Japanese documentation at the time and has a gain of 70 dB, being powered by p V. The input sensitivity is only 12 mV.
This simple unregulated power supply with half-wave rectification is for small appliances that do...
Found in an American book from the 1960s, this circuit uses a photoelectric cell of the time as a...
In the publication in which we found this circuit, it is suggested for applications in clandestine...