Replacing Variable R with LDR in light dimming circuit

Thread Starter


Joined Mar 16, 2010
Hi, I am constructing a light dimming circuit that is based on light sensing LDR, Automation/efficient-energy-management/light-dimmers.php (Refer to Figure 3)

I am not constructing the external circuit in this case because I would the LDR to sense from the surrounding light. I would like to ask:
1.What should be the value of the LDR resistance?
2.How should I test the circuit? What are the precautions when testing it in a home 230 v power supply?
3. Whats should be the dimmable lamp power rating?
4.Other alternative model for the TRIAC?

Thank you in advance.


Joined Sep 9, 2010
You won't find support here for mains-connected projects like this one, for safety reasons. Your questions may be answered by careful reading of the component datasheets.