Led spans.

[Felino]

If i wanted to make an array of our favorite thing, leds, which is better, running them in series or parallel? Would i am trying for efficiency here, my array would probably consist of around 30 leds to start off with. Red, green, and blue, see what i am getting at?

I will need to have seperate control of each colour, then hooking up with a pic, with a transistor so that i can use pwm to control seperate channel. I plan to have the leds in a straight line, as below.

Code: Select all

R-G-B-R-G-B-R-G-B-R-G-B

Would i be better switching them as a group, ie, all the reds, with one large transistor, or as smaller groups say 4, with a smaller transistor?

-Felino

[Mario]

If i wanted to make an array of our favorite thing, leds, which is better, running them in series or parallel? Would i am trying for efficiency here, my array would probably consist of around 30 leds to start off with. Red, green, and blue, see what i am getting at?

I will need to have seperate control of each colour, then hooking up with a pic, with a transistor so that i can use pwm to control seperate channel. I plan to have the leds in a straight line, as below.

Code: Select all

R-G-B-R-G-B-R-G-B-R-G-B

Would i be better switching them as a group, ie, all the reds, with one large transistor, or as smaller groups say 4, with a smaller transistor?

-Felino

For efficiency, I would say control same-colored leds with one big transistor. I mean, if you wired up a transistor for every led, that would be a ton of work!

[Felino]

I also read about the voltages i would need for them in series, how much would that be for 10 leds, am i right in thinking around 20v?

[vskid]

I also read about the voltages i would need for them in series, how much would that be for 10 leds, am i right in thinking around 20v?

Ya, 20-30v for 10, they're about 2-4v each depending on color and size.

[Felino]

Mmm, boost converters ar not really my thing, so proably 40v is not the best thing to use, its probably parallel then.

Still not sure about the transistor thing though.

[Felino]

Lastly, sorry bou the bump, but could i run this without resisters, since i will be using pwm, and i keep i under say, 50% duty?