LDR power consumption

Forum 2005-2010 (read only) Hardware Interfacing
1

I've just got a quick question that I didn't find an answer to (might be I didn't look closely enough, if so I apologize).

When running an arduino on a battery while constantly reading measurements from an LDR, does the arduino consume more or less power if it is in a dark or brightly lit room?
Basically, what I'm thinking is that since an LDR is a variable resistor, the amount of current it allows through depends on the amount of light it is exposed to. But does this have an effect on the overall mAh consumption?

Appreciate any information on the subject :slight_smile:
Kjetil.

2

I guess the short answer is depending on how you hook up your LDR the answer could go either way.

That said, LDR's current draw is pretty small, if it changes between 10K to 1M in value due to the brightness change, the current change is less than 0.5 mA.

3

Thanks, AlphaZeta.

Then I guess I shouldn't worry too much about that part of the equation.
If it matters, I've connected the LDR from 5v to analog, with a 1K resistor from analog to ground.

Cheers.

4

That's correct. Good luck!