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 simple demonstration circuit was found in a Popular Electronics of the 1980s. It can be...
In the figure we have the application of a general purpose diode in the gain control of a...
This sole beacon which has a battery charged by photocells was found in documentation from 1991....