This circuit comes from a Gernsback Publications of the 90s. The circuit uses a general-purpose transistor as a sensor. The power supply must be symmetrical.
This circuit appears elsewhere in this section and on this site. The circuit generates a linear...
The circuit shown has the advantage over the reductions with resistors to have a much higher...
This circuit was found in a 90s Popular Electronics. Both the coupler and the MOSFET can be of any...