This circuit, which can be used as a shield, was found in Radio Electronics from the 90s. The operating circuit can be replaced by a lower voltage equivalent.
We found this circuit on Radio Electronics from July 1990. It triggers a relay with a touch of the...
These three circuits have different treble responses. We found them in the February 1970 issue of...
This photoelectric cell light relay was found in Radio Electronics magazine from April 1958. The...