LED Lighting Again

["rb_ziggy" <richard.boreham@xxxxxxx>]

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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