We found this circuit in the June 1992 issue of Radio Electronics magazine. The sensor is a common diode. The circuit is powered by the power grid from a 12 V transformer.
This circuit was adapted from an Italian publication that no longer exists. This is “Onda Quadra”...
This circuit was obtained in an Electronic Engineering of the 90s. The operational amplifiers and...
The basic component of this circuit is a general-purpose SCR. The voltage is according to the...