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 is from the Philips manual of 1990. The integrated circuit is not very common. The...
We found this configuration in a 1974 technical documentation. The circuit consists of a filter to...
Other operational amplifiers in the series, such as the MC34072, MC34074, MC35071, MC35072,...