This circuit was found in a 70s documentation. The transistor is from that time. L1 has 4 turns of wire 20 in the form of 3/32 inches and L1 has 10 turns of the same wire,
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...