4 useful circuits with LDR 

Hello friends!
In this video i will show to you four usefull circuits which we can make with LDR (light depend resistor).
The first is when is dark the light is on!
The second when os light the light is on!
The third concerns an auto light and works in ac of mains!
And the fourth is an alarm system in which a laser light is involved and can be upgraded with many ways!
Enjoy the video!