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.
The original frequency of the Pierce Oscillator with bipolar transistor is given by the crystal, which...
Used in radio reception, this circuit was found in the February 1983 Radio Electronics magazine. The...
We found this circuit in the Linear Applications Handbook of the National Semiconductor of 1994....