Using a 709 integrated circuit this circuit was found in the June 1972 issue of Radio Electronics magazine. More modern operational equivalents can be used. The power supply is symmetrical.
This source for devices for automotive use was found in a 1985 documentation. The power...
We found this circuit in an old Popular Electronics. It is possible to light a common neon lamp...
This circuit has an opposite action to the previous one, triggering when light falls on the...