Light Dark switch activated relay circuits

This Light Dark switch activated relay circuits schematics are the simplest electronic circuits that can help you to activate other electronic device at the light or dark .
This Light Dark switch activated relay circuits are very simple and require one electronic relay and other few common components that are not critical . For Light Dark switch activated relay circuits you need to use a 5-6 volts electronic relay .

The R2 potentiometer is used to adjust the trigger on level .The diode in the diagram shows to be 1N914. This is ok if you have a light-duty relay, also the 1N914 is a signal diode so actually does not qualify.
If you don’t find the 1N914 you can substitute it with a 1N4001 diode (or better) instead. The 2N2222  (Q1) transistor can be substitute with :NTE123A, ECG123A, PN100, or other similar types . The R1 component is a photo resistor .