The design provided here is very compact and can be used for switching ON a group of LEDs automatically when dusk falls and switch them OFF when day breaks.
You will need the following parts to make an automatic day night LED lamp circuit:
A veroboard, four numbers of diode 1N4007, a couple of BC 547 transistors, resistors with the values of 2k7 and 1k, a filter capacitor of 1000 uF / 25 volts, a preset of 1K, some LEDs as described in the diagram and the resistors for limiting the LED current, a PPC capacotr having a value of
How to make an automatic day night LED lamp:
Cut the veroboard to approximately 4 by 4 inches.
Fix the transistors first and then go on connecting the rtest of the parts just as illustrated in the CIRCUIT DIAGRAM.
Beware the circuit is very dangerous to touch when switched ON, so maintain extreme care while touching the involved parts.
The circuit functions in the following way:
Suppose there’s no light falling on the LDR and apparently it’s dark around the LDR. This increases the resistance of the LDR which inhibits the following transistor from conducting which in turn switches ON the transistor carrying the LEDs and the LEDs are also switched ON.
Exactly opposite happens when light falls on the LDR when the LEDs are all switched off.