spacehonkey
New Member
I'm a complete NOOB at this stuff. This is my first attempt to put a circuit board together and it shows. I'm trying to build a light sensitive switch so whenever I cover the LDR it energizes the relay. I have everything setup on a breadboard just like it shows on this link **broken link removed** but it doesn't seem to work. I shot the components and they're all good. I did find out that even though the voltage from the LDR does decrease, from 10Vdc to 4.5Vdc, when I cover it it doesn't change the output voltage of the OpAmp. The output from the OpAmp will only adjust when I physical adjust the resistants on the trimmer pot. Also the relay clicks over the instant I power up the system. I think the transistor has something to do with that because I disconnected the OpAmp from the system and the relay was still energized. I then took out the transistor and the relay turned off. I'm probably way off on how a transistor works but I thought the collective wouldn't read the ground coming through the emitter until the base had voltage running though it. I'm not sure what I'm doing wrong.
Can anyone out there help me out?
Can anyone out there help me out?