The figure shows a remote-control receiver working the 27 MHz band, very popular in the 60’s. The circuit us from a February 1961 Radio Electronics magazine.
This conventional window detector circuit was found in a 1995 documentation. The trigger points, that...
This circuit activates a relay when the sensor receives light. The sensor can be any common LDR,...
Versions of this circuit have appeared several times on this site and even in this section. This...