This small audio amplifier was found in an American publication in 1975, The integrated circuit used is rare today. The circuit was used in portable receivers of the time and other applications.
This circuit uses opposing MOSFETs operating on a 6 to 15 V input voltage. The circuit is from...
The sensor of this circuit is a photodiode. Equivalent operations can be used, and the instrument can be...
Charcoal microphones are rare today. In the figure we have a circuit that shows the use of one of...