This circuit with 10 MHz and 1.25 MHz TTL outputs was found in an American documentation from the 1980s. The used integrated circuit is uncommon today.
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...