This circuit was found in an English publication from 1967. The circuit is for listening on a phone. Transistors are types of germanium of the time.
This low noise audio amplifier step uses only one transistor and is high enough to operate with low...
August 2016 –It can be purchased from Mouser Electronics the new converters BD7F100 and BD7F200...
This circuit can be used as a shield for microcontrollers. The circuit is from American...