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If you
put 3 LEDs in series you only need one resistor per 3
LEDs
Power
disipated (WASTED) by the resistor is also reduced to a third as it is only
dropping 3v now.
also
using the series method you are lighting 3 LEDs with only 20mA compared to
60mA
if driven individually.
Total
power consumption is now 33% of what it would have been.
Smaller transformer + thinner wire + less power = lower running
costs = more money left for toys :-)
Keith
www.diyha.co.uk
www.kat5.tv
Personally i would use 12vdc bus to power them
and use current limiting resistors for each Led . The resistor
value would be approx 450 ohm (470). It was calculated as
follows
the led voltage = 3v approx so 9v must be
dropped
across the resistor . The current = 20mA divide voltage (9V) by
.02
and hopefully the answer is 450 otherwise ive
just made a fool of myself .Leds should not be connected in parallel
without
individual resistors as one robs the other of current .
Frank Mc
----- Original Message -----
Sent: Wednesday, April 24, 2002 9:13
PM
Subject: RE: White LED Lighting... was
RE: [ukha_d] Re: ADSL vs Cable
Straight off, these can't be dimmed by X-10 in the way
you mean Nikola, as
they are not 240v replacements.. they are simple
components, reqiring a 3V
supply. It seems you wire them in
serial/parallel networks to provide a 12V
system, which can then be used
in a system similar to existing 12v Halogens.
The devices themselves
vary their light output dependant on current, so they
can be dimmed
quite
easily, you just need a bit of circuitry to do so.. (or
possibly, a
dimmable transformer would do the trick.. my leccytronics isn't
good
enough to be sure)
Ian.
-----Original Message-----
From:
Nikola Kasic [mailto:nikola@xxxxxxx]
Sent: 24 April 2002 11:47
To:
ukha_d@xxxxxxxSubject: RE: White LED Lighting... was RE:
[ukha_d] Re: ADSL vs Cable
I might be interested, but I'm not
sure.
Can you tell me can they be dimmed using some kind of X10
dimmer?
I'm looking for some lighting solution for my hallway. I want to
put
recessed lights because utility room doors ara just 2-3 cm below the
ceiling
and they hit the current light unit and broke it. But my problem
is that my
suspended ceiling (plasterboard) is just 5 cm from concrete
ceiling. That's
not enough for putting any halogen light, because of the
heat. That area is
not ventilated, of course, it's just a plasterboard
screwed onto wooden
battens.
Could this be a solution
then?
Nik
-----Original Message-----
From: Ian Lowe
[mailto:ian@xxxxxxx]
Sent: 24 April 2002 10:00
To:
ukha_d@xxxxxxxSubject: RE: White LED Lighting... was RE:
[ukha_d] Re: ADSL vs Cable
yeah,
I found a company in
korea doing MR14 MR16 sized replacements for the small
Lv Halogens, in
20W equivelants. These were clusters of 15 LEDs, each
producing about
3Cd..
Since digging more and more, I found a maglite like torch
quiting a 42
Candela output in white, using THREE LEDs!! it was also
100,000 year (Ten
Years continuous use) LED life, and about 100 hours on
three AA cells..
so I had a further rummage, and found what I
believe
to be the highest rated
white LEDS available on the market
now...
12 Candela units, from computronics in Australia. (they are
selling a bag of
500 for about ?300 + shipping)
The bizzare thing
for me is this:
the 2500mcd ones use 20mA at about 3.8V
optimal..
And the 12000mcd ones, despite being nearly five times
brighter use, er,
20mA at about 3.8V
I'm totally
smitten!!
The idea of having a cool crisp light (I like a slight
blue
tint at the best
of times, so the lack of any "red" component doesn't
bother me) that can be
used with normal usage patterns for 25 years and
uses about >ONE< Watt in
place of a 50W Halogen, whilst producing
an equivelant 80W light level is
pretty amazing..
I'm having
ideas
of totally cool under cupboard lighting, but having twice
as much light
for about 4% of the leccy... :)
more research required...
as
an aside, if we don't get a European supplier, is anyone interested
in
chipping in for some of the LEDs from Computronics. I think it works
out at
about 60p each. ?
Ian
-----Original
Message-----
From: paul_watkin [mailto:paul_watkin@xxxxxxx]
Sent:
23 April 2002 20:31
To: ukha_d@xxxxxxxSubject: White LED
Lighting... was RE: [ukha_d] Re: ADSL vs Cable
Nichia have the
brightest white LED's on the market at about 6.4cd in
a T1 3/4 package
or
3.2cd in T1
http://www.nichia.co.jp
Not sure
who in Europe holds a disty franchise for Nichia though, try
Arrow, EBV
somebody like that. I'll try and find out who it
is
tomorrow.
Other companies to look at are Panasonic, Lumiled
(Agilent and
Philips Joint venture to replace the lightbulb with led's)
and also
Agilent Technologies.
Although you would probably need
an
account with somebody like Arrow
or EBV to get access to stuff from the
above suppliers.
Regards
Paul
--- In ukha_d@y...,
"PatrickLidstone" <patrickl@t...> wrote:
> >
> >
Due
to really awful search functions (and every electrical
appliance
>
> containing LEDs), I can't find details. There is a 3mm LED
on
the
> Maplin
> > site
> > (http://maplin.co.uk/products/details.php?
>
cartid=0204231835361451415&modulec
> >
ode=&moduleno=17821&manufacturer=Nichia). I based my thoughts
on
> the
> > variety of LED torches around.
>
>
Rapid Electronics do a separate opto-electronics catalogue
-
probably
> worth a gander.
>
> You'll find full tech
specs on RS (Radio Spares) and Farnell
websites
> for a huge range
of LEDs.
>
> Patrick
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