Originally indicated as an alarm alert in a 1990s US publication, this circuit can be used as a shield to control a strobe lamp. The sensor is a optocoupler with LDR.
This timer was found in a 1994 Electronics Now. The relay must be a sensitive type. If it has a...
We can make an oscillating relay producing a rectangular signal taking advantage of the inductance of...
This circuit appears at various points in this section and on this site, with minor variations. It uses the...