LED Lightbulb replacements

S

Steve

Guest

• Dec 21, 2005

• #21

Austin Shackles wrote:

> beats me. I invite anyone to call in and observe, though. You can also
> observe the same effect on Grumble... the amber flashers aren't as bright as
> you might expect.
>
> If I get some pennies, I might buy some of superbrightleds "4 inch truck
> lamps" which are 25 bucks apiece. they'd make nice trailer lights. see
> what they're like. They'd go quite nicely on the back of a landy, of
> course, too

I think it might be that the orange ones might make it from yellow and
red, yellow is closer to the most sensitive bit of our vision than red,
so you see it as brighter. Its an effect from our vision, not the physics.

Steve

 

A

Austin Shackles

Guest

• Dec 21, 2005

• #22

On or around Wed, 21 Dec 2005 18:22:10 +0000, Steve
<[email protected]> enlightened us thusly:

>Austin Shackles wrote:
>
>> beats me. I invite anyone to call in and observe, though. You can also
>> observe the same effect on Grumble... the amber flashers aren't as bright as
>> you might expect.
>>
>> If I get some pennies, I might buy some of superbrightleds "4 inch truck
>> lamps" which are 25 bucks apiece. they'd make nice trailer lights. see
>> what they're like. They'd go quite nicely on the back of a landy, of
>> course, too
>
>I think it might be that the orange ones might make it from yellow and
>red, yellow is closer to the most sensitive bit of our vision than red,
>so you see it as brighter. Its an effect from our vision, not the physics.

yebbut, the orange ones look *less* bright than the nominally dimmer red
ones.
--
Austin Shackles. www.ddol-las.net my opinions are just that
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S

Steve

Guest

• Dec 21, 2005

• #23

Austin Shackles wrote:

> yebbut, the orange ones look *less* bright than the nominally dimmer red
> ones.

Maybe its not that colour combination then ? Try the CD spectroscope test,
http://sci-toys.com/scitoys/scitoys/light/cd_spectroscope/spectroscope.html

Red should be dimmer, unless the LED emission angles are different,
which would affect the optics.

Steve

 

T

Tom Woods

Guest

• Dec 21, 2005

• #24

On Mon, 19 Dec 2005 22:44:44 +0000 (UTC), "David J. Button"
<[email protected]> wrote:

>and you didn't have light protectors on - tut tut!

Depending how fast the tree jumps out at you they might not always
help!

 

K

Karen Gallagher

Guest

• Dec 22, 2005

• #25

Steve Taylor wrote:
> Karen Gallagher wrote:
>
>> LED's are current driven, not voltage driven - fit no resistor &
>> something will have to blow or burn. You should be able to look up
>> the required current for the LED you have and chose a resistor to
>> suit the voltage you're running at, then the LED will work
>> correctly. Resistor in series, of course, not in parallel.
>
>
> Surely the vehicle lights have integrated resistors, for the fixed
> supply ? BTW not only do you need the required current, but the
> forward voltage drop of the diode, which varies with the LED
> technology, from
> 1.2 V to 4-ish for white Luxeon Lumileds.
> Then R= (Vsupply-Vf)/I where Vf is the forward volt drop, I is the
> current in Amps. R is then in Ohms.
>
>
> Steve

Not all have integrated resistors - especially if, for example, someone is
replacing dash panel light bulbs with LEDs, you'd not be installing a kit of
any sort.

An elementary introduction to LEDs is available in many places on the web,
here's one example some might find useful if you want an introduction to LED
technology: http://www.eleinmec.com/article.asp?6
Though it's a Pommie web page (prices are in UK £) LEDs are available pretty
much anywhere, and the data tables for them too.

Karen

--
"I'd far rather be happy than right any day."
- Slartibartfast

 

D

David G. Bell

Guest

• Dec 22, 2005

• #26

On Wednesday, in article
<[email protected]>
[email protected] "Austin Shackles" wrote:

> On or around Wed, 21 Dec 2005 15:03:43 +0000, Steve Taylor
> <[email protected]> enlightened us thusly:
>
> >Austin Shackles wrote:
> >
> >> what's odd is that the amber bulbs are made with LEDs at 8800 mcd each max.
> >> axial intensity, while the red ones are 7500mcd. But the red ones look
> >> brighter, subjectively, than the amber ones, in identical bulb housings.
> >>
> >
> >
> >What's even odder is this goes against the photopic sensitivity curves
> >of the eye ( http://www.resodance.com/ali/pho_sens.html if you're
> >interested )- or, we can't see red as well as we can see orange . Orange
> >is a LOT closer to our peak sensitivity than red.
>
> beats me. I invite anyone to call in and observe, though. You can also
> observe the same effect on Grumble... the amber flashers aren't as bright as
> you might expect.

There's four different sorts of light sensitive cells in the eye, three
of them sensitive to different colours, and quite a bit of image
processing in the optic nerve and brain. So that rather reddish
incandescent bulb doesn't look anything like as red to us as it does to
a camera.

So that red could be close to one of the local peaks in the curve, while
the orange has more total sensitivity, but is off-peak on two colour
receptors.

The eye's responses are more complicated than simple graphs can show.

--
David G. Bell -- SF Fan, Filker, and Punslinger.

"I am Number Two," said Penfold. "You are Number Six."

 

A

Austin Shackles

Guest

• Dec 22, 2005

• #27

On or around Wed, 21 Dec 2005 21:45:34 +0000, Tom Woods
<[email protected]> enlightened us thusly:

>On Mon, 19 Dec 2005 22:44:44 +0000 (UTC), "David J. Button"
><[email protected]> wrote:
>
>>and you didn't have light protectors on - tut tut!
>
>Depending how fast the tree jumps out at you they might not always
>help!

"warning - heavy plant crossing"
--
Austin Shackles. www.ddol-las.net my opinions are just that
Blue: The sky is blue for a reason. Blue light is a source of strength
and harmony in the cosmos. Create a blue light in your life by
telephoning the police
from the Little Book of Complete B***ocks by Alistair Beaton.

 

A

Austin Shackles

Guest

• Dec 22, 2005

• #28

On or around Thu, 22 Dec 2005 16:05:52 +1000, "Karen Gallagher"
<[email protected]> enlightened us thusly:

>Not all have integrated resistors - especially if, for example, someone is
>replacing dash panel light bulbs with LEDs, you'd not be installing a kit of
>any sort.

depends how you do it. sundry of the typical dash panel bulbs are
available.

http://www/superbrightleds.com has LED replacements for several of the
smaller bulbs.
--
Austin Shackles. www.ddol-las.net my opinions are just that
Blue: The sky is blue for a reason. Blue light is a source of strength
and harmony in the cosmos. Create a blue light in your life by
telephoning the police
from the Little Book of Complete B***ocks by Alistair Beaton.

 

T

Tom Woods

Guest

• Dec 22, 2005

• #29

On Thu, 22 Dec 2005 19:30:58 +0000, Austin Shackles
<[email protected]> wrote:

>On or around Wed, 21 Dec 2005 21:45:34 +0000, Tom Woods
><[email protected]> enlightened us thusly:
>
>>On Mon, 19 Dec 2005 22:44:44 +0000 (UTC), "David J. Button"
>><[email protected]> wrote:
>>
>>>and you didn't have light protectors on - tut tut!
>>
>>Depending how fast the tree jumps out at you they might not always
>>help!
>
>"warning - heavy plant crossing"



They always seem to cross behind you too...