Found in the December 1974 issue of Radio Electronics, this circuit is similar to the previous one, only using another TTL counter. The circuit must be powered by 5 V.
This circuit uses two light-activated SCRs or LASCRs, uncommon components today. The power depends on...
This type of configuration can be seen elsewhere in this section. This is from a 1965 General...
Crystals from 100 kHz to 1 MHz can be used in this 1957 Raytheon circuit. 4 can have values...