We found this circuit in the July 1992 issue of Radio Electronics magazine. An optical system produces the light beam that, when interrupted, triggers the alarm. The sensitivity is adjusted by R4.
This circuit is from Ferranti documentation from 1967. The operational is of the time, but the...
This simple circuit can be used in a robot that follows the light directly feeding a small motor....
This circuit makes the simple test of SCRs that have a low maintenance current, with those of the...