This circuit came out in a publication called Electronics Handbook of 1993. The circuit shows how to implement a good common telephone line protector.
The circuit is from the 1994 National Semiconductor Linear Applications Handbook. The component used is...
This circuit, which is present in other points of this website, was found in a 90s Hands On...
This simple circuit produces a tone when triggered by any vibration picked up by the sensor. The...