Controlling brightness for a DC incandescent light

Forum 2005-2010 (read only) Hardware Interfacing
1

Hello all,

first post, and possible dumb question. :slight_smile:

I am looking to control, via Arduino, The brightness of a DC incandescent light bulb (12v-24v). Like the type you would find in a typical hand held flashlight (torch).

Now I have played with the PWM dimming samples and LEDs, but I would need something additional for an incandescent light as it requires more power, right?

I searched the forum, and found dimming applications for AC, but I am thinking this has got to be much simpler. I imagine it would involve adding more resistance in series with the bulb or controlling the voltage across the bulb leads?

Any suggestions?

thanks!
-rob

2

To control an incandescent bulb, you need to use a transistor; look at the examples in the playground and elsewhere for controlling a relay or solenoid. The only difference would be that you don't need the diode across the load (in a relay or solenoid, the coil - in your case, the lamp), because there is no inductive kickback.

Then, drive the transistor with your PWM signal as normal...

3

Great, thanks for the tip.

BTW, I am looking into these opto-isolated solid state DC relays for another switching application.

http://www.opto22.com/site/pr_details.aspx?cid=4&item=DC60MP

Could these also be used be used for dimming the DC light as well (by driving it with PWM)??

I know this would not work well with a mechanical relay (not fast enough). But I am not that familiar with these relays.

thanks