high visibility in leeds

Just to let you know of a new shop in Leeds called Active Workwear at
56 Bradford Road, Pudsey, opposite Chris Richards Motorcycles!!!!
that can supply all manner of High Visibility and or waterproof outer
clothing clothing at competetive rates email or tel 0113 256 6655

 

Got anything in black?

 

Got any HiVis Kilts?

 

Using the patented Mavis Beacon "Hunt&Peck" Technique, mike

Look mummy, a spammer.

Oh, and look! A spammer's phone number. What *fun*...

 

" Hello, can I speak to Mr Brightstripe please, first name Ivor."

 

**** off.

--

Dave

GS 850 x2 / SE 6a
SbS#6 DIAABTCOD#16 APOSTLE#16? FUB#3
FUB KotL OSOS#12? UKRMMA#19

 

That would be the new ultraviolet reflective black leathers, that only
highlight you when being approached by boy racers with blue LEDs on their
cars.
(Yes, I do know, I have one of those blue LED torches, it makes
flourescent things show up rather well, meaning it produces a fair old
whack of UV.)

 

I thought LEDs only produced one wavelength, therefore if you can see
them they aren't doing UV?

 

Dunno, but it's a blue LED and it charges up glow in the dark things
quicker than a normal lightbulb, and makes flourescent things flouresce
rather brightly. A plain blue wavelength wouldn't actually make it
flouresce, would it - as flourescence is due to reflecting UV?

 

I bet a car crashes into it. SMIDY.


--
Alan

http://www.ads-training.co.uk
"Kneesliders Sponsored by Cane"
GSX-R1000 , Triumph Thunderbird, ZXR750L2 Racer(gone), GS500,
GHPOTHUF#27
TGF, UKRMFBC#7, Two#24, BOTAFOF#11, YTC#9, GYASB#1. SbS#23.
DFWAG#2, DS#2, DIAABTCOD#20. remove "thisbit" in the reply
http://sportsbike.org (our own endurance team) http://Team-ukrm.com
"Nemo repente fuit turpissimus"

 

If all it did was reflect UV then it wouldn't do anything - you wouldn't
be able to see it. It absorbs then re-emits the light at a longer
wavelength, shifting it towards red colours. It's all to do with
electron shells, IIRC my physics correctly.

Therefore, it could be UV as you say, but it could also be just blue or
violet light. This doesn't prove that LEDs do or don't produce one
wavelength. I suspect they do, as different colours are made using
different gasses. When used in light production gasses typically only
produce one wavelength.

If any of the resident physicists want to jump on my sweeping
statements, feel free.

 

I don't think that's the case. AIUI each electron/shell jump would
emit a photon at a given wavelength determined by the energy expended
to make that jump, but most gases consist of many shells with
different energy levels.

Consider most domestic flourescent lights. They generate a reasonable
approximation of white light, don't they? Consisting of a very wide
range of different wavelengths.

IANAP. Should I have let that stop me?

 

Gasses in LEDs? Nope.

LEDs work by combining electrons with holes at the interface
between two different types of semiconductor. The electron + hole
then gives up some energy, which is specific to the types
of semiconductor. Multiwavelength semiconductors use multiple
"blocks"[1] of semiconductors.

[1] I'm not sure of the exact configuration.

 

Yes, but I thought they were made up of other LEDs. I'm happy to be
proven wrong, and an explanation of how it's done would be welcome.

 

Well, you'll need some semiconductor physics.

http://www.physics.gatech.edu/advancedlab/labs/photoelectric/photoelectric-3.html
is a bit technical.

You might want to start here:
http://britneyspears.ac/physics/basics/basics.htm

(seriously)

 

Aha. I assumed semiconductors, doping, gasses, one wavelength. Little
knowledge, and all that I think.

Ta muchly.

 

Ah yes, but that's made up from as little as 5 different gasses mixed,
giving off 5 wavelengths. I thought each LED made 1 wavelength, and
you'd stick multiple ones in one lens to create white or compsite
colours.

However, will's given the word, so I obviously need to do some reasearch
in the physics section next time I'm at the library.

Hell no. This is UKRM.

 

Indeed; not fantastically "white" though.

 

Harsh, but fair.

 

SMIWD

Sorry mate i was dazzled.