This circuit without sensors in series triggering an SCR was found in volume 5 of the 1995 Encyclopedia of Electronic Circuits. The circuit can have the number of sensors changed.
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...