"white" LED's vs. incandescent and halogen lights

On Dec 16, 12:11*pm, Chalo wrote:
SMS wrote:

[BellSports]
I guess Trek and Specialized are also anti-cyclist companies, LOL.

Trek and Specialized haven't (to my knowledge) lobbied for laws that
reduce participation in cycling and make it harder on those of us who
remain. *I don't love them, but I don't havegoodreasons to avoid
their products.

Chalo

Dear Chalo,

http://www.newyorker.com/humor/issue...e=2#showHeader

Cheers,

Carl Fogel

Tom Sherman °_° wrote:
Andrew Muzi wrote:

Minus five F again this morning.
No crowds in my way just before dawn. Didn't see even one bicycle this
morning.

Even the one you were riding?

Don't ... look ... down!

Mark J.

On 17 Dec, 04:57, Tom Sherman °_°
wrote:
Paul Oosterhout wrote:
Clive George wrote, On 12/16/2009 10:13 AM:
"Paul O" wrote in message
...

Chalo wrote, On 12/15/2009 7:38 PM:

snip
I used to get VistaLite 5-LED rear flashers because they used AAs.
When I discovered that VistaLite was owned by the anti-cyclist company
Bell Sports, I started buying Planet Bike blinky lights instead. *I
don't prefer the AAA battery size, but in practice it does not seem to
be a problem.

Chalo

Chalo,
Mind if I ask why you consider Bell Sports to be an "anti-cyclist
company". Is there something going on with Bell Sports that I'm not
aware of?

It's pretty obvious to anybody who's read these NGs for more than a
couple of months.

I think I know what you are getting at and I will just drop the matter
here...

We have not had a h*lm*t discussion in a while.


They have been supplanted by foam caps.

On Tue, 15 Dec 2009 17:00:01 -0800 (PST), Chalo
wrote:

There is a critical difference. Incandescent bulbs radiate out most
of their heat instead of retaining it in the device. And they are
made of glass and metals that are relatively tolerant of high
temperatures. An LED dumps all its heat within the semiconductor die,
which can easily burn itself up if it does not have an adequate path
through which to discharge waste heat. LEDs are damaged by relatively
low temperatures-- for example, residual heat from soldering their
leads can harm them if joints are not soldered quickly enough.

I do actually know all this, I have a degree in electrical
engineering. I also have LED front and rear lamps and don't recognise
more than a tiny fraction of the issues Steven seeks to raise as
insurmountable obstacles.

Guy
--
http://www.chapmancentral.co.uk/urc
GPG public key at http://www.chapmancentral.co.uk/pgp-public-key.txt

Chalo wrote:
Just zis Guy, you know? wrote:
SMS wrote:
In any case, I don't think anyone's touched on the biggest reason why it
isn't practical to do drop-in replacements of a 3W LED to replace a 3W
filament bulb. The 3W LEDs generate a large amount of heat at the
semiconductor junction, and require very good heat sinks.
Yes, it's well known that incandescent "bulbs" (lamps, Steven, they
are called lamps) emit no heat whatsoever.

There is a critical difference. Incandescent bulbs radiate out most
of their heat instead of retaining it in the device. And they are
made of glass and metals that are relatively tolerant of high
temperatures. An LED dumps all its heat within the semiconductor die,
which can easily burn itself up if it does not have an adequate path
through which to discharge waste heat. LEDs are damaged by relatively
low temperatures-- for example, residual heat from soldering their
leads can harm them if joints are not soldered quickly enough.

I think that LEDs got the reputation of generating no heat from
low-power "being seen" LEDs. Non-engineers like Guy don't realize that
an LED is actually a semiconductor with a junction.

On Thu, 17 Dec 2009 21:04:06 -0800, SMS
wrote:

Non-engineers like Guy don't realize that
an LED is actually a semiconductor with a junction.

Non-readers like SMS don't know what B.Eng (hons) MIET means.

Guy
--
http://www.chapmancentral.co.uk/urc
GPG public key at http://www.chapmancentral.co.uk/pgp-public-key.txt

We have not had a h*lm*t discussion in a while.

=v= So what? Unless somebody actually has something to say that
hasn't already been spewed onto Usenet 100 times before, there's
really not point.

=v= And no, coming up with "Hell Mutts" because it wasn't yet
in everyone's *plonk*files does NOT qualify as actually having
something to say. It only qualifies as being obnoxious.
_Jym_

Jym Dyer wrote:
We have not had a h*lm*t discussion in a while.

=v= So what? Unless somebody actually has something to say that
hasn't already been spewed onto Usenet 100 times before, there's
really not point.

It was tongue in cheek.

=v= And no, coming up with "Hell Mutts" because it wasn't yet
in everyone's *plonk*files does NOT qualify as actually having
something to say. It only qualifies as being obnoxious.
_Jym_


Boo hoo.

--
Tom Sherman - 42.435731,-83.985007
I am a vehicular cyclist.