This circuit found in the February 1992 issue of Radio Electronics magazine is designed to adapt an audio signal for use in a computer's ADC. It can be adapted to operate with microcontrollers.
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...