[HELP] LDR (Light Dependent Resistor)

Discussion in 'General Electronics Chat' started by rdolloh, Nov 8, 2012.

  1. rdolloh

    Thread Starter New Member

    Nov 7, 2012
    Equipement-- * ATX Power Supply, 5V and 12V * 9V, 18V, 27V and a 36V battery setup (4x9V) * LDR's; Different sizes, not sure what specifics. * Light bulb 5W; 1.5 Ohms * CPU fan 300k Ohms and runs on a 12V power source ------------------------------------------------------------------------------------------ When I connect the CPU fan on a 12V circuit, with the biggest LDR nothing happens until I change the 12V into 36V and shine a strong light source on the LDR. But when I connect the light bulb of 5W instead of the CPU fan and I shine a strong light source on the biggest LDR, nothing happens (The small LDR I have fails with all setups). Any suggestions? I want to make the light bulb give light when the smallest light source (i.e. daylight) shines on the LDR.
  2. Wendy


    Mar 24, 2008