This circuit allows the use of an electret microphone with a 1.5 V source. We found it in the Encyclopedia of Electronic Circuits volume 5 from 1995.
This small transmitter with 2 transistors can reach several hundred meters using a 30 to 70 cm...
This circuit was found in a Modern Electronics from 1990. It activates an old electromechanical pulse counter,...
Although the integrated used originally is uncommon today, more modern operating equivalents can...