Found in Popular Electronics from the 90s, this circuit uses still common components. Its power is 20 W, requiring care when winding the transformers.
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...