This is an automatic light switch circuit (Photocell), can run 220v lamps in night automatically up to 10A.
Advantages of this circuit:
1-have 5 seconds delay time
2-can run up to 10A load
3-can use for any lamp types such as LED, CFL, low pressure sodium, high pressure sodium, ...etc.
4-adjustable light sensitivity by potentiometer
4-adjustable light sensitivity by potentiometer
Parts list:
Transistor 2N5551(2pcs)
Relay 12v
LDR
Potentiometer 25k
Bridge diode 1A
Zener diode 12v 1W
Diode 1N4007
Capacitor 330-820uF 400v
Capacitor 100uF 25v(2pcs)
Resistor 270 ohm 2W
Resistor 10k
Resistor 2.2k
Resistor 33 ohm
Resistor 270 ohm 2W
Resistor 10k
Resistor 2.2k
Resistor 33 ohm
you must put it in a small transparent plastic box for electric and moisture insulation.
NOTES:
1-Don't touch the circuit when it connected to electric line.
2-Put it away from lamps light (above the lamp)
As you see in this pic. i used 3A relay rather than 10A to make the circuit small as possible since my loads consume very low current
In following video you can see step by step making this Photocell:
