This circuit was found in Linear Technology documentation from the 90's. The circuit uses components from that time, and can be powered by 5 V. In these conditions, it can function as a shield.
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...