PCB - Rs 79.00 each
Assembled Board - Rs 179.00 each
Automatic Day Night Off On Street Porch Garden 12v LED Light Board
A simple board use as Dusk to Dawn Light or Emergency Light
12v operation Solar panels support up to 20w.
Sensitivity of the LDR can be adjusted via Preset.
Mains Power is applied via 0 - 15 volts transformer, it is rectified via D1,D2,D3,D4 Diodes and given to U1 voltage regulator.
The output voltage of U1 is set between 15.5 volts to 16.5 volts via RV1.
12 volts Battery is charged by this constant voltage variable current through D5 and R4.
when the Battery Voltage reaches 15volts, zener D6 turns on transistor Q1, cutting off U1 and stopping charging current.
The LED's are Controlled by LDR, in light LDRs have low resistance so Q3 will not turn on.
in Darkness LDRs have high resistance so Q3 will turn on the LED lights.
Always keep the LDR in the Shadow of LED's. LDR sensitivity towards light / Darkness can be adjusted via RV2.