We found this circuit in the October 1987 Radio Electronics magazine. The circuit uses a 1-to-1 turns ratio pulse transformer to trigger the Triac.
This circuit was found in a 1992 documentation and has excellent sensitivity, using components that...
This practical idea from a 1992 documentation shows how to count the turns of a winder using a...
In this circuit from the 60s, the power supply is made with 22.5 V, which is the voltage of the...