The picture there, shows red and black wires on the LED module.
Red would be the +12V wire. Black would be ground. Polarity is
important, because more than the safe reverse voltage is being
applied to the LEDs. (Unlike computer case front panel LEDs,
which are safe to reverse, due to only +5V being used.)
If you want a copy of an ATX power supply spec, you can get one here.
Section 4.5.3 PDF page 38 Molex wire colorshttp://
www.formfactors.org/developer/specs/ATX12V_PSDG_2_2_public_br2...
Purchase a Molex "Y" cable. That will give you connectors and wire
to work with. A "Y" cable scheme, one per LED array, will also make
it possible to extend a single Molex from the power supply, to run
multiple loads.
+---- (LED array - where female connector used to be)
|
Molex_Male ----+---- Molex_Female
Cut the yellow and one black wire away from one of the female
connectors. That is your source of power. If you're lazy, you
can leave the remaining red and black on that Molex, as it
means less work to insulate wire ends.
Connect yellow from Molex, to red on LED array.
Connect black from Molex, to black on LED array.
Cover the joints with heatshrink tubing (Polyolefin) or (ugh!) electricaltape.
You don't want any bare wires to touch stuff in the case,
since "sparks will fly".
Specs are here (not as complete as I'd like).
http://www.maplin.co.uk/Media/PDFs/Module 47376.pdf
Using the picture on that spec sheet, or looking at the color picture
in the following link, you can see there are surface mount current limiting
resistors already distributed along the strip. Depending on the LED color,
the population of resistors varies. Some strips have pairs of
resistors, others have single resistors per clump of LEDs.
http://www.omc-uk.com/ShowDetails.asp?id=1311
I can't be absolutely certain, but it could be constructed like this.
Red ------------+------------+-----> to ten more columms
(+) | |
resistor resistor
| |
LED LED
| |
LED LED
| |
LED LED
| |
Black ----------+------------+-----> to ten more columns
The total strip current is 280ma. There are 12 columns. That is
23.3 milliamps per column. The forward bias voltage of each
LED, varies with the color, so as the color of the LED strip
is changed, different value resistors must be used. If the
power dissipation limits of one resistor are not sufficient,
that may be a reason for a pair of resistors next to one another.
You can prepare your own schematic of the strip, using a multimeter
set on ohms, to trace the circuit. It would have been nicer if they'd
provided a schematic.
The strip expects a regulated supply, and all the numbers
in the spec sheet, apply at the stated voltage. So when
fed 12V, you'd expect 280mA current flow, with some room
for unit to unit variation.
I would expect their 24V version is an entirely different
design. It would be more likely to have six LEDs in the
column for example. If they continued to use three LEDs per
column, the resistors would get quite hot.
The most efficient way to run them, is in columns like that.
An even more efficient way, is to power them from a
current regulator or current source, but then the
regulating device's efficiency must be considered
as well.
Paul
i test the led's yesterday with the Car