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Quite Correct Keith
But from a wiring point of view were there are a string
of
leds along a skirting in a hallway for instance i would imagine
wiring
them individually using speaker wire in parallel would be easier especially
for guys who are not into electronics.The 3 in series is good for a
cluster were you need more lite .
Frank Mc
----- Original Message -----
Sent: Wednesday, April 24, 2002 10:19
PM
Subject: RE: White LED Lighting... was
RE: [ukha_d] Re: ADSL vs Cable
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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