We found this circuit in the October 1987 Radio Electronics magazine. The triac must be controlled according to the heater. The transformer has a low current, of the order of a few hundred mA.
This circuit activates an output, which can be a lock, only when a card containing the programmed code...
Found in an October 1992 Radio Electronics magazine article, this circuit generates a low-power tone in...
Found in a manufacturer documentation from the 90s, this circuit makes use of period components. The...