Re: LED Lighting Again

["Frank Mc Alinden" <fmcalind@xxxxxxx>]

Hi Richard


>        suggested the series wiring was fine but
> parallel not such a good idea - something about current flow not
> being evenly divided. Any views on this?

You can wire them in parallel but each led should have its own
resistor.....I did some led garden lighting using 12v and series the leds
in
groups of 3 with a series resistor for each group....Wiring in parallel
means the resistors must dissipate more power as you need approx 10v to
drop
across the resistor   whereas the series setup is only a few volts.......

> One other query - has any one any idea how much power a, say, 12V
> supply draws when connected to the mains but not supplying to its
> supplied device.  Curious really as they often feel warm.  Or am I
> just being daft here

Wouldnt be worth worrying about.........

HTH
Frank

----- Original Message -----
From: "rb_ziggy" <richard.boreham@xxxxxxx>
To: <ukha_d@xxxxxxx>
Sent: Friday, January 02, 2004 7:43 AM
Subject: [ukha_d] LED Lighting Again


> Following on from Andy Laurence's experiences of LED lighting I've
> decided to take the plunge for an 'automated' wardrobe.  Well ok, it
> will be automated to the extent of lighting coming on as you enter
> the dressing room at night and the interior will illuminate as the
> door open.
>
> This is my first foray into this so a few queries (sorry if obvious)!
>
> From Andy's description it appears the LED's were wired to the power
> supply in parallel (I infer this as each had the same resistor and it
> looks like there was quite a few of them, so running in series from a
> 9V supply looks unlikely???).  Could someone confirm this works
> fine.  I ask as another site referenced a while back (Lee's LED Guide
> at www.leesspace.com/LEDs) suggested the series wiring was fine but
> parallel not such a good idea - something about current flow not
> being evenly divided. Any views on this?
>
> My intention is to wire up two 'legs' to one power supply.  The first
> will supply (prob just one or two) LEDs to provide a low level night
> time illumination when someone enters the area (PIR triggered,
> switched via a relay on Comfort). The second leg is a simple switch
> on the wardrobe door to illuminate the interior. Any views on this?
> (A 1 amp regulated supply should easily satisfy the total set of
> LEDs).
>
> One other query - has any one any idea how much power a, say, 12V
> supply draws when connected to the mains but not supplying to its
> supplied device.  Curious really as they often feel warm.  Or am I
> just being daft here. (I had thought about switching at the mains
> side - e.g. an X10 appliance module - but this would obviously use
> two separate supplies and appliance modules.)
>
> Regards
>
> Richard
>
>
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