This 555 IC circuit was found in the November 1994 issue of Radio Electronics magazine. The circuit can be powered by voltages from 12 to 24 V.
In this circuit, obtained from a 1979 publication, IC1 is a 555 and IC2 is a 4020. The transistor is the...
The presented circuit uses a window comparator to keep a relay activated only when the sensor is...
Similar circuits can be found on this site. This is from an 80's American documentation. The...