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.
Placed in the vicinity of a telegraphic transmitter (CW), this circuit produces an audible signal on...
This circuit provides 2.5 W of power with 6 V supply and 4-ohm speaker. We found it in the Radio...
This circuit was found in Intersil's documentation from the 70's, being indicated for powering...