This circuit incorporates the passive control of the previous circuit and was also found in the March 1995 Electronics Now magazine. The power supply must be symmetrical.
This circuit causes an LED to flash if the monitored voltage exceeds the value set in the pot. The...
Found in an Electronics World of 1966 this circuit can be made with current power transistors. It causes...
Found in a 1970 documentation, this SCR bistable can be implemented with modern equivalent SCRs. Observe...