Re: Multiple LEDs

In article <aPv6g.22780$vy1.20022@xxxxxxxxxxxxxxxxxxxxxxxxxx>, "Farticus" <localhost@xxxxxxxxx> wrote:
Hi,

My customer has requested me to supply some PCBs populated with 120 LEDs to
form a single light, and to be driven by a 12 volt supply.

They suggest that the LEDs be wired in groups of 6 in series (2 x 6 = 12v)
with each group having a single series resistor. Then the total of 20 of
these groups to be connected in parallel
thus providing a series/parallel solution.

They claim that this method (they have previous ongoing experience) is
better than placing all in parallel for two reasons. First the consistency
of brightness of the LEDs wired in series is better than when wired in
parallel, and secondly less heat is generated from the use of a single
resistor if LEDs are wired in parallel. (+/- 30W) as well as the space taken
by the single large wattage resistor.

Does anyone in the group have experience/comments in this regard?

What do you see as the correct solution?

I have wired 64 in series parallel with only one resistor. I have wired
9 high power LED's with no resistor and a variable supply for testing purposes. No problems.
I suppose the LED's should be tested for consistancy.
greg
.

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