This circuit was originally suggested in a 1968 publication to generate a white mark (frame) on a film at regular intervals to serve as a time reference.
This Philips circuit of the 70's makes use of components of the time. The DZD40 is an uncommon...
This circuit with two operating modes was found in the September 1989 issue of Radio Electronics...
This circuit is from an old documentation making use of a 3,579,645 MHz analog color television...