This flip-flop controlled by an LDR-type photocell was found in Radio Electroinics magazine from June 1959. Note that it can be powered from the mains and directly controls a sensitive relay.
This conventional window comparator configuration was found in an old documentation. It is valid...
This circuit for analog instruments was found in a Raytheon documentation from the 1960s....
This circuit in a receiver that allows the capture of distant stations with short waves. The...