Here are some DIY LDR switch circuits available on our website and the web. LDR switches are used to switch a relay or other device when light are present or absent. LDRs or Light Dependent Resistors ...

Forepart of this circuit section is a 5mm photoresistor (LDR).This component is used to trigger the relay latch circuit wired around the planar passivated, very sensitive gate silicon controlled ...