This circuit is from the 80's but uses common components today. The relay is voltage sensitive according to the power supply used. Transistors may be general purpose types.
SAM D5x and E5x MCUs Provide Powerful Performance and Enhanced Security Features CHANDLER, Ariz.,...
Found in a 1968 EEE, this circuit accepts frequencies from 1 to 1000 Hz and control voltages from 0.1 to...
Dwell meter is the English name given to the opening angle meters of old plated cars. We found this...