This circuit was obtained from the September 1977 issue of Radio Electronics magazine. The circuit is based entirely on transistors and two SCRs. The power supply with the inclusion of a battery is given.
This circuit is given in two versions, having been found in a publication from the 90s. The second...
This circuit was found in an ancient American documentation. Used integrated circuits are uncommon...
This Texas Instruments circuit uses a phototransistor to fire a TTL trigger port. Other...