Dashboard LED's

Dave Burns · Post by **Dave Burns** » 27 Feb 2004, 00:40

Some interesting clobber here, not cheap though.
http://www.ultraleds.co.uk
Dave

uhn113x · Post by **uhn113x** » 27 Feb 2004, 12:53

Hi (Marty?)
<blockquote id="quote">quote:<hr height="1" noshade id="quote">Didnt think thst was an issue when using LEDs of the same type? (ie all 5mm Hyperbrite Blues in this case) <hr height="1" noshade id="quote"></blockquote id="quote">
Yes - even a tiny difference in Vf will make a big difference to the current. Say you have 10 LEDs, even all from same batch - lowest Vf 2.5, highest 2.52.
If you connect them in parallel and calculate the series resistor to give 20mA, they will ALL have 2.5v across them, so that the current drawn by those with the highest Vf will be much less - the low one will act as a zener. In extreme cases, the highest one may not even turn on.
Mike

Paulxmski · Post by **Paulxmski** » 28 Feb 2004, 06:44

Hi yu all,
Ref leds my local store in Bletchley has keychain bright light led lights with red,blue, green and yellow leds they work off 2 x 2016 0r 1 x 2032 at 3 volts and they're £1each the 2032 batteries fit the XM remote and the whole thing is cheaper than most shops charge just for the battery, mayb four of them could be strung together for real christmas tree dash effect ha ha!

Post by **martyhopkirk** » 28 Feb 2004, 14:19

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by uhn113x

Hi (Marty?) - Yep Marty!
[quote]the low one will act as a zener. In extreme cases, the highest one may not even turn on.
Mike
<hr height="1" noshade id="quote"></blockquote id="quote">
Ah well, - I stand corrected. Its a loooooong time since i did my Btec in electronics (which i failed - which is why i became a nurse) but i never had any probs with the fiesta dash, as far as i know its still working as i see it occasionaly and the dash is still blue.