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 voltage regulator was obtained in the SGS manual of linear integrated circuits of 1982. The...
Of course, the design indicates a specific application for a touch switch. Thus, analyzing the...
In the figure we have the way to obtain the Exclusive-OR function with 1 transistor. The circuit...