This circuit was found in Radio Electronics from the 90s. The components used are common, and the transistors and CIs must be equipped with heat sinks.
This contact or reed switch actuation was found in a 1964 Electronic Design. The circuit can be...
This is the previous version, but with a simplification given by the use of the 7404 and 7408...
In the figure we present a circuit of a microphone signal conditioner using the SSM2167 integrated...