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Re: LED lighting for garden
- To: ukha_d@xxxxxxx
- Subject: Re: LED lighting for garden
- From: Ian Oliver <ioliver.lists@xxxxxxx>
- Date: Fri, 20 Apr 2001 10:27:21 +0100
- Delivered-to: rich@xxxxxxx
- Delivered-to: mailing list ukha_d@xxxxxxx
- Mailing-list: list ukha_d@xxxxxxx; contact
ukha_d-owner@xxxxxxx
- Reply-to: ukha_d@xxxxxxx
> I didnt fully read the earlier posts regarding the intended use, but I
> assume this is just for a decorative effect rather than illumination.
These
> LED's are extremely bright but have a VERY narrow viewing angle, some
less
> than 20 degrees.
Yes, decorative, so we want to throw beams onto and into trees.
> With LED's you MUST have a resistor to limit the maximum current
throught
> them to a safe value. Taking the White LED's on the page you mention,
> Forward voltage @ 20mA is 3.6V so placing several in series would add
up as
> follows 3.6, 7.2, 10.8 (limit for a 12v supply) 14.4, 18v, 21.6 (limit
for
> 24V supply). 3 LEDs on 12V needs a 60 ohm resistor to drop the excess
1.2V
> nearest standard value is 62R. 6 LED's on 24V needs a 120 ohm resistor
> (standard value)
> Power rating should be 0.6W Metal Film Resistor
Thanks for that. I'll get some LEDs and experiment. Anyone know a good
source in the
UK? I've checked Farnell but they seem quite expensive. OK, for a few to
experiment,
but no good for doing the job for real.
Regards
Ian Oliver
Using Java on Tini for control via Dallas 1-wire
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