The schematic given here is a project of an automatic night light / lamp using 555 IC. The circuit will automatically activate six 5mm LEDs at night when you close your room light or when there is no light on the surface of the LDR. The circuit is using a 230V AC capacitor power supply. The 330nF / 400V film

capacitor drops the AC mains. The bridge of four 1N4007 diodes rectifies the voltage comings from the 330nF capacitor and converts it in to DC voltage. The 220uF 16V capacitor is used to filter the voltage coming from the diode bridge. The voltage is then goes in the LM7812 voltage regulator IC that steps down the voltage to 12V DC for operating the night light circuit.

The night light circuit is built around a 555 timer IC. The LDR (Light dependent resistor) or photoresistor is used to sense the Light. When the daylight or room lamp light falls on the surface of the LDR its resistance decreases hence the 555 IC makes the LEDs off. At night time when there is no light on the surface of the LDR the resistance of LDR increases due to which the 555 IC activates the LEDs. The sensitivity of the circuit can be adjusted with 50K variable resistor. The circuit is not using any transformer and directly connected to the AC therefore do not touch any component of the circuit when it is connected to the AC mains.

Note: Many points of this circuit are at AC mains voltage. It could give you lethal shock if you are not careful. If you don't know much about working with AC line voltages do not attempt to construct this circuit.
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Automatic Night Light / Lamp Using 555 Circuit