This Vox or sound activated relay was found in an American documentation from 1975. Equivalent transistors can be used, and the SCR can be a TIC106. The relay is according to the supply voltage.
The 78xx series is manufactured by several semiconductor companies that present ideas for use in...
This alarm siren was found in volume 5 of the 1995 Encyclopedia of Electronic Circuits. The...
This circuit can be implemented with other comparators in the same series. The circuit is from a...