This two-microphone amplifier was found in a April 1961 Radio Electronics Magazine. The circuit is powered by battery and has a 600-ohm line output.
This very old circuit, from a publication from the 1970s, uses a germanium transistor and two...
In the figure we have a very sensitive touch switch circuit. A touch of the sensor causes the...
In fact, we can say that this circuit found in documentation from the 90s, consists of an intercom...