This circuit was found in a 90s Popular Electronics. It produces a muted tone similar to that produced by a bell. The signal must be applied to an amplifier.
This circuit is from a 1995 publication; The current is obtained by dividing 1.25 by R1. The...
We found this circuit in an old American publication. It is possible to test common FETs using a...
This circuit was obtained in a 90s documentation from Analog Devices. The sensitivity is in the...