This simple sensitive circuit was suggested in a July 1992 Radio Electronics issue. The relay is a double-contact changeover relay. Sensitivity adjustment is made at R2.
The trigger element of this circuit is a neon lamp. The SCR admits an equivalent. We found it in...
We found this circuit in a 1992 documentation. It consists of a digital signal splitter used in...
This circuit can use any comparator or even an operational amplifier. We can use the LM339 and the...