LED project - need some guidance

Thread Starter


Joined Apr 27, 2010
Hi all,

I was a little hesitant to post yet, because I don't want this to seem like a "please do this for me post", but I could use some advice. :)

I am working on a project to use LEDs to back light translucent plexiglass panels. I am looking at using PLCC2 surface mount type LEDs (current 2ma, 3.0 min voltage). I need something small (physically) so that I can sandwich the LED's between two sheets of plexi.

I expect to have around 25 panels in the project, and with my current level (lack of:D) of knowledge, was thinking that each panel would have 5 LEDs in series and all panels wired in parallel (125 LEDs total). If I am correct, that will be 2.5amps total (.02ma x 125 = 2.5a).

If these numbers are correct, what voltage power supply will I need? From a wizard I found online, I believe 24volts is needed, but with my limited knowledge at this point, I am not sure how to confirm that. And if 24volts is right, I've come up with needing a 470 ohm resistor for each panel.

Am I even close to being on the right track?

I obviously want a toggle switch to cycle power, but I also want the ability to dim the LEDs and don't have a clue what I need for this.

To give you some background, I have dabbled with electronics before, but nothing on this scale. I am currently reading the E-book which is helping tremendously (and was also how I found this forum) but I still have much to learn. I've also ordered several different types of LEDs to experiement with as I am really a "hands on" learner. However, I want to be sure I am not going to hurt myself either! :)

Thank you!



Joined Aug 7, 2008
With 5 LEDs @ 20mA.in series that is still just 20mA/ panel X 25 = .5A. Resistors of 450 to 470 @ 1/4 W should be OK with 24V supply.

Thread Starter


Joined Apr 27, 2010
Thanks guys! Trying to read through the article now, but I think it will take several attempts to comprehend.


Joined Mar 24, 2008
No problem, we have a lot of people who don't mind answering questions, myself included. Don't hold back because you think it sounds silly, this is how we learn.