Hi

I have a store some 5km away... but anyway, it seems its possible to
webshop at least in Ikealand.

http://www.ikea.com/ms/sv_SE/customer_service/how_to_e-shop/how_to_e-shop.html

--

Björn

For those who don't speak swedish try:

<http://www.ikea.com/ms/en_GB/customer_service/how_to_e-shop/how_to_e-shop.h
tml>

Dave

-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of bg@lysator.liu.se
Sent: 30 January 2010 16:01
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] [OT] Ikea Lamp

Hi

I have a store some 5km away... but anyway, it seems its possible to webshop
at least in Ikealand.

http://www.ikea.com/ms/sv_SE/customer_service/how_to_e-shop/how_to_e-shop.ht
ml

--

Björn

time-nuts mailing list -- time-nuts@febo.com
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Robert Atkinson wrote:

Traditional LEDs might not be optimized for speed, bug being GaAsP based
they are probably not too shabby. InP and other fun (and fast) materials
is used. Digging up on LEDs led me over YAG to bubble memories.

Interesting side-effects of this discussion is that one learns more in
fields one does not ponder too much over normally.

Cheers,
Magnus

Chuck Harris wrote:

I got one of these so called 2D fluorescent tubes in a packet and bought it home
on the train late in the evening. The trains are electric with cables overhead.
What was strange was that the lamp was glowing dimly in the packet - I can only
assume the E field from the overhead cables for the train was the source of power.

Dave

Dr. David Kirkby wrote:

I should have added, it carried on glowing for some time after I got home too.
At that point, I was well away from the train lines, though we do have 11 kV
overhead cables around 30m from the house. It eventually stopped glowing so I
assume it was the presence of the overhead train lines which caused this.

Hi Paul:

LEDs come in many flavors of white.  The ones called warm white can be
very comfortable but they are not as bright as the plain white or cool
white LEDs.

Also high power LEDs can burn your eye.  Not because they emit UV but
rather just because they are bright, like the Sun.
http://www.prc68.com/I/LED.shtml#Atlas  This is a 7 Watt LED that burned
my eyes.

Wien's displacement law relates the wavelength emitted from a hot body
to it's surface temperature.  For numbers for the Sun or a human see:
http://www.prc68.com/I/Probeye.shtml#WaT
Planck's law took another five years to relate frequency and surface temp.

Have Fun,

Brooke Clarke
http://www.PRC68.com

paul swed wrote:

Or, possibly, your radiant personality :). - Mike

Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960

-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Dr. David Kirkby
Sent: Saturday, January 30, 2010 12:47 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] White LED's

Dr. David Kirkby wrote:

I should have added, it carried on glowing for some time after I got home
too.
At that point, I was well away from the train lines, though we do have 11 kV

overhead cables around 30m from the house. It eventually stopped glowing so
I
assume it was the presence of the overhead train lines which caused this.

time-nuts mailing list -- time-nuts@febo.com
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and follow the instructions there.

Clarke
Sorry to hear that you hurt your eyes. I suspect many are unaware of the
risk.
I have experimented with higher power LEDs but nothing like 7 watts so very
good to have learned something. I have to say even looking at the lower
power LEDs you get the feeling that looking straight on is not a good idea.

My wife used some of the new LEDs on a christmas tree this year. We didn't
like them and turned them off using just the traditional lamps. She now
understands what a point source is.
Also if straight on they were quite bright off angle 12 degrees they were
pretty dim.

I have tinkered for a while looking for effectively spread leds for panel
meters. I dislike changing lights in my radios. But the LED simply do not
spread light the way lamps do.

Like your idea of the flexible trouble light.

On Sat, Jan 30, 2010 at 12:55 PM, Brooke Clarke brooke@pacific.net wrote:

Dr. David Kirkby wrote:

When I was a kid, there was a main set of high tension power lines several
hundred yards from my house.  I had friends that had garden sheds under the
towers that were lit by fluorescent lamps collecting the stray fields.  A
piece of wire on each end of the bulb enhanced the effect.

I knew of one guy that had a big coil of wire in the roof of his shed
and he could light a 100W incandescent bulb from the stray fields.

-Chuck Harris

If you care about accurate colour rendering, stick with incandescent,
preferably halogen.  "White" LEDs are actually blue LEDs coated with a
phosphor that absorbs some of the blue light and emits approximately
yellow instead.  If you look at the spectrum, you'll see a broad yellow
peak and a narrower blue peak.  Your eyes see it as approximately white,
but it's deficient in red and green compared to a black body emitter
like hot tungsten.  On the other hand, it's not as spiky as the output
of fluorescents.

The particular IKEA units I have both look approximately "daylight" in
colour temperature, and the colour is pretty uniform across the
illuminated field (except for the very edge, which is yellow, but that's
probably due to chromatic aberration in the lens, not the LED source).
They work better than most of the LED flashlights I've seen, which tend
to have large intensity and colour changes between the centre and the
edge of the illuminated field.

 Dave

On 30/01/2010 07:49, paul swed wrote: