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Crossed messages - Frank - yep - saw what you
meant
when I reread the post ( see other reply) - I have difficulty thinking
above
three after a long lunch, sometimes even before . You can save two
resistors though at 2p ea - oh - forgot there's the extra wire though
;).
Kevin
-
Look
after the milliwatts and the watts will look after
themselves.
Hi Kevin
But
if for instance you have 12 leds on your
skirting which will all operate together you
have
to get a supply from the first one to the 4th one to the 7th one the to the
10th one and all to save .2w per led. The parallel system requires you to
put
the resistor at the tap of point or at the led .The serie application would
suit what i have in mind eg Garden lites.
Frank Mc
----- Original Message -----
Sent: Wednesday, April 24, 2002 10:44
PM
Subject: RE: White LED Lighting... was
RE: [ukha_d] Re: ADSL vs Cable
The wiring complexity is really the same in both
situations - you need just two wires to each led - in the series solution
you save four connections as you lose two resistors and also you only have
to break one of the wires at each LED so you save 3/6 connections
there. You just interrupt one strand of the cable at each led (except the
last one) v having to connect across each time. If anyone wants I'll draw a
diagram.
Kevin
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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