Found in a Motorola's 1968 documentation, this circuit operates at 16.5 kHz. The output is 5 A. The transistors are from the era, admitting modern equivalents.
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...