This circuit for the power grid was found in the June 1969 Radio Electronics magazine. The SCR and diodes are rated according to the power of the controlled load.
The purpose of this circuit is to allow common analog multimeters to measure low resistances, on...
We found this circuit in a Radio Electronics issue from July 1969. The lamp remains on until C1...
This circuit was found in a 90s Popular Electronics. The sensor can be any phototransistor. ...