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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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