This circuit is from a 1978 magazine Radio & Electronics Constructor, but it can be assembled with 1N4004 diodes and TIC106 SCRs for motors up to 1A. The transformer has a secondary 12 V x 1 A.
This 1995 circuit uses interruption sensors or NC connected in series in any quantity. With the...
This circuit, suggested by a 1975 documentation, detects an electrical discharge in a storm by...
Found in an old Electronic Design, this circuit provides an output voltage that is the absolute...