This circuit activates an old cassette recorder when the phone is being used, thus making it possible to record the conversation. The circuit is from a Hands On Electronics from the 90s.
This fiber optic receiver was obtained from a 1978 documentation. We can use any modern...
This circuit was found in a Popular Electronics documentation from the 90s. It is possible to switch...
This circuit was found in an old Motorola documentation from the 70s, as it uses one of its...