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Re: Fw: Replacement Super Bright LED lights
Benfield, John (GTI EMEA) wrote:
> LED's work off constant current rather than voltage, therefore you
> cannot dim them by reducing the voltage - they carry on working at
full
> brightness until they suddenly turn off.
Ah, they're Luxeon stars, aren't they - so presumably have a constant
current power supply attached to them which wouldn't take kindly to
being dimmed.
The LEDs themselves most definitely do not behave the way you describe
though :-)
> This probably not too good for
> the transformer/driver. You can dim LED's but most systems have a
dimmer
> that accepts a separate 1-10v control line. In this case the driver is
> also performing the dimming (by changing the current).
>
Any LED can be dimmed by scaling the voltage, although it's thoroughly
non-linear. Pulse width modulation is the usual scheme for dimming a LED
- that's probably what the dimmable ones use, controlled by the extra
input.
Jim
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