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Nic
I
was going to mention that in my reply to Keith that someone would suggest
putting 4 in series
with no resistor but didnt in case he thought
i was trying to be a smart arse . You need a resistor to limit
the
current.
Frank Mc
----- Original Message -----
Sent: Wednesday, April 24, 2002 10:36
PM
Subject: RE: White LED Lighting... was
RE: [ukha_d] Re: ADSL vs Cable
Keith, why not put 4 LEDs in series and you don't need any resistor?
Or
it's not reliable?
Nik
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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