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Topic: Clean and energy efficient LED dimming (Read 4 times) previous topic - next topic

MrGlasspoole

0.5 Meter?
It's a house. There are 5-10 meters...
I found this driver: http://www.leds.de/out/media/KSQ.pdf
And they write to make the cable from the supply not longer then 1,5 meters.
Or is it that they assume that power cables are always unshielded?

lax123

#26
Feb 17, 2013, 06:18 pm Last Edit: Feb 17, 2013, 06:25 pm by lax123 Reason: 1
uhh 20 meters, i read in one of your first posts..

well a cable is like a resistor...the longer the cable the bigger the resistor...
http://www.elektronik-kompendium.de/sites/grd/1003191.htm


so maybe ur input supply is 12V with a cable of 20meters maybe only 10V depending on load "arrive" at the end of the cable

heres a calculator:
http://www.bmc-braunschweig.de/de/sonstiges/78.html

MrGlasspoole

@lax123, i thank you that you want to help me. But that is basic stuff i know.

And this calculator shows what i don't understand. Why so big and short cables for LED's?
I read stuff like 0.75mm2 - 1.5mm2 on most sides.
But if you look at eldoLED POWERdrive they write 3 meters to the LEDs.
And they write 0.2mm2 per 1 ampere.
They also wrote somewhere that 6 meters is no problem with CAT cable and also wrote that
they have customers who made up to 50 meters.

What i can't find is a answerer to PWM over longer distance.
If i have a LED driver with PWM in - how long can i make the PWM line from the Arfuino
to the driver.

There is also the option to dim analog. This would change the color temperature a little.
But i can't see in the Cree datasheets what color temperature at which ampere.
They write color temperatures from 2600 to 4300 for the XP-E High-Efficiency White LEDs.

Damn is this LED stuff complicated when it comes to dimming.
I wish i had a oscilloscope :D

lax123

Hi,

can you link the source?
Quote
But if you look at eldoLED POWERdrive they write 3 meters to the LEDs.
And they write 0.2mm2 per 1 ampere.

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