Dark Sensitive Switch Using CA3140

Dark Sensitive Switch is a simple project which operates a relay when the light falling on the LDR goes below a set point.  This circuit is built using CA3140 Op-amp and can also be considered for use in energy saving application.

Input – 12 V @ 50 mA
Relay output – SPDT relay
Onboard preset to set the level
Relay On LED indicator
Power Battery Terminal (PBT) for easy relay output connection
Four mounting holes of 3.2 mm each
PCB dimensions 44 mm x 51 mm