This circuit makes use of an integrated LM2907. The circuit is from an old documentation being applied to cars that still used platinum, common at the time.
This application is from a circuit manual from the 90s and only works with incandescent lamps. The triac...
This circuit was found in an American magazine in 1978. It activates a relay when the speed of a...
This circuit is from 1976 documentation, but it can be assembled with more modern transistors like...