Suitable for clandestine listening and in SMD assembly, this circuit was found in the Radio Eletronics magazine of August 1988. The listening is in headphones and the amplifier is electret.
This circuit has a 100 dB dynamic We found it in a Popular Electronics from the 90s. Equivalent...
This 80's circuit uses a germanium transistor like the AC121. The circuit has an output...
May 2017 - Mouser Electronics already has inventory with ROHM BD570xx integrated circuits for...