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Hi Kevin
I just wish computing was as easy as connecting leds .
Maybe
the Computer guru,s can help me make sense of all their jargon .Anyway for
you
me Keith Ian B and other electronic buffs series parallel doesnt
matter
but for the non electronic people make it nice and easy .
Frank Mc
----- Original Message -----
Sent: Wednesday, April 24, 2002 11:04
PM
Subject: RE: White LED Lighting... was
RE: [ukha_d] Re: ADSL vs Cable
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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