The Sun – Up Relay Switch can be used to provide a audible switch for when the sun comes up. It can also be used to detect a light beam, headlights etc.
When the light leaves work suddenly. When meet the light makes Photo Transistor work bias current change it has made the transistor works to cause Relay work with. For VR1 perform fine decorate the rapidity of the circuit. This circuit is the circuit is simple.
The equipment that use to replace can. such as Q1 = 2N2222 use other number can replace almost be finished request a kind NPN alike enough such as BC549 or BC337 or C1815 or C945 etc. For oval should use 6V-9V sizes that are valuable the resistance within relay coil about 500ohm. Other detail has a little , then build easily sir.
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