Having had many, many droplight bulbs go over the years from dropping or
even just bumping them, (the cage keeps the glass from breaking, usually,
but the filament goes anyway) I finally discovered an improvement. NJ is
currently offering an instant rebate on compact fluorescent "bulbs". These
are really cheap right now, so I put one in my droplight the other day while
looking for a new bulb. Works fine, stays very cool (which is always an
advantage under the car with the light next to your head), and gives 100W
equivalent light. I haven't dropped it yet, but I suspect that it will be a
lot more robust. Sure a lot cheaper than the ruggedized "drop light bulbs"
they sell for this application (which are not a lot more rugged than
ordinary bulbs, in my experience.

Metal content: (1) The cage on mine is made of metal. (2) The cars I work
on with it are mostly metal. :-)

--
Bob (Chief Pilot, White Knuckle Airways)

I don't have to like Bush and Cheney (Or Kerry, for that matter) to love
America

"Bob Chilcoat" wrote in message
...
Having had many, many droplight bulbs go over the years from dropping or
even just bumping them, (the cage keeps the glass from breaking, usually,
but the filament goes anyway) I finally discovered an improvement. NJ is
currently offering an instant rebate on compact fluorescent "bulbs".
These
are really cheap right now, so I put one in my droplight the other day
while
looking for a new bulb. Works fine, stays very cool (which is always an
advantage under the car with the light next to your head), and gives 100W
equivalent light. I haven't dropped it yet, but I suspect that it will be
a
lot more robust. Sure a lot cheaper than the ruggedized "drop light
bulbs"
they sell for this application (which are not a lot more rugged than
ordinary bulbs, in my experience.

That's funny. I've always used "rough service" type bulbs and have had
excellent luck with them, even when dropping. The only negative I've
experienced with them is that the bulb darkens considerably as the filament
evaporates and deposits on the inside of the bulb. Mine usually die from
old age, and by then I'm happy to see them gone because the light I'm
getting is quite poor. Thanks for the tip on the fluorescent light,
though. I do prefer the nice, white (and cool) light they provide.

Harold

Harold & Susan Vordos wrote:
"Bob Chilcoat" wrote in message
...

Having had many, many droplight bulbs go over the years from dropping or
even just bumping them, (the cage keeps the glass from breaking, usually,
but the filament goes anyway) I finally discovered an improvement. NJ is
currently offering an instant rebate on compact fluorescent "bulbs".

These

are really cheap right now, so I put one in my droplight the other day

while

looking for a new bulb. Works fine, stays very cool (which is always an
advantage under the car with the light next to your head), and gives 100W
equivalent light. I haven't dropped it yet, but I suspect that it will be

a

lot more robust. Sure a lot cheaper than the ruggedized "drop light

bulbs"

they sell for this application (which are not a lot more rugged than
ordinary bulbs, in my experience.


That's funny. I've always used "rough service" type bulbs and have had
excellent luck with them, even when dropping. The only negative I've
experienced with them is that the bulb darkens considerably as the filament
evaporates and deposits on the inside of the bulb. Mine usually die from
old age, and by then I'm happy to see them gone because the light I'm
getting is quite poor. Thanks for the tip on the fluorescent light,
though. I do prefer the nice, white (and cool) light they provide.

Harold


Well I've been running a 12W fluorescent for about 4 years in my
inspection lamp. As we have bayonet fittings over here the additional
mass of the ballast on the base of the bulb worried me a bit as it
wasn't snug in the fitting, so I fitted a rubber O ring as packing
between the bottom of the ballast and the top of the holder. No more
blown bulbs :-)

Also if anyone has a failed tubular inspectin lamp with the resistive
cord instead of a proper ballast, if you nick the circuit board out of a
9W bulb, it will run the tube in the inspection lamp just fine. Just
match up the filament connections and fit a new mains lead. I pulled
one out of a skip in a marina, and found that the lamp had a blown
filament at one end as well. I put a 33 ohm
resisor accross the blown filament which let the ballast get enough
current through it t warm up the other filament enough to start. Its
been running like that for about 9 months of occasional use now
(probably a week or two of continuous duty)

--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk [at]=@, [dash]=- &
[dot]=.
*Warning* SPAM TRAP set in header, Use email address in sig. if you must.

In article ,
"Harold & Susan Vordos" wrote:

"Bob Chilcoat" wrote in message
...
Having had many, many droplight bulbs go over the years from dropping or
even just bumping them, (the cage keeps the glass from breaking, usually,
but the filament goes anyway) I finally discovered an improvement. NJ is
currently offering an instant rebate on compact fluorescent "bulbs".
These
are really cheap right now, so I put one in my droplight the other day
while
looking for a new bulb. Works fine, stays very cool (which is always an
advantage under the car with the light next to your head), and gives 100W
equivalent light. I haven't dropped it yet, but I suspect that it will be
a
lot more robust. Sure a lot cheaper than the ruggedized "drop light
bulbs"
they sell for this application (which are not a lot more rugged than
ordinary bulbs, in my experience.

That's funny. I've always used "rough service" type bulbs and have had
excellent luck with them, even when dropping. The only negative I've
experienced with them is that the bulb darkens considerably as the filament
evaporates and deposits on the inside of the bulb. Mine usually die from
old age, and by then I'm happy to see them gone because the light I'm
getting is quite poor. Thanks for the tip on the fluorescent light,
though. I do prefer the nice, white (and cool) light they provide.

Harold

I also use rough service bulbs that are dipped in some sort of
translucent rubber like material... they don't shatter when/if they get
splashed. I've also had excellent life spans with them.

I've also drilled two holes in the reflector, and installed two short
1/4-20 bolts from the inside out, with nylock nuts on the outside that
act as 'anti roll' feet.

My droplight will lie stable on it's back or either side. A most handy
modification.

I can put up a dropbox photo if anyone's interested.

Erik

Bob Chilcoat wrote:

Having had many, many droplight bulbs go over the years from dropping or
even just bumping them, (the cage keeps the glass from breaking, usually,
but the filament goes anyway) I finally discovered an improvement. NJ is
currently offering an instant rebate on compact fluorescent "bulbs". These
are really cheap right now, so I put one in my droplight the other day while
looking for a new bulb.
snippage

I also discovered this some years ago when our electric company and
Benny's stores were giving them away..Did my whole house up..except
where I need to see fine detail, like in the shop. There I still use a
combination of flourescent and filament to get a nice color balance.
They can take a beating...I've had the same one in my droplight for
three years at least and it's been dropped many times, gotten wet a few
times, and it is still going .... Gotta love it!




--
Paul
'91 XL1200
'77 GL1000 (W.I.P.)
"I feel more like I do now than when I got here"

Recently our local power company has been recommending replacing
incandescent bulbs with compact flourescent for energy savings. I've found
that the color of these are rather harsh and that the colors also vary from
one manufacturer to another. Sometimes the color temperature is listed on
the package but without something to reference it to, it is worthless to me.
What is the color temperature of a standard incandescent? Better yet, I
like the color of halogen bulbs, where do they fall?

Thanks,

Shawn

On Fri, 03 Dec 2004 21:19:46 GMT, Erik wrote:

BIG SNIP
I also use rough service bulbs that are dipped in some sort of
translucent rubber like material... they don't shatter when/if they get
splashed. I've also had excellent life spans with them.

Also called "Food Service" bulbs. Fluorescent can be purchased with
that same coating, and the idea is that if they break (get hit) they
won't fall in food, or in the case of elevators, onto people. Neither
of these are very common though, as in both the food and elevator
service, full lenses (lites) are used instead.

"Erik" wrote in message
...
snip-----.

I've also drilled two holes in the reflector, and installed two short
1/4-20 bolts from the inside out, with nylock nuts on the outside that
act as 'anti roll' feet.

My droplight will lie stable on it's back or either side. A most handy
modification.

Damned good idea! Nothing irritates me more than my light turning over when
I'm under a car and can't reach it easily. Needless to say, it's always
pointing in the wrong direction. I think your description is more than
adequate without posting a pic, at least for me. Thanks for the tip, Erik.

Harold

Excellent idea.
Karl
"Erik" wrote in message
...
In article ,
"Harold & Susan Vordos" wrote:

"Bob Chilcoat" wrote in message
...
Having had many, many droplight bulbs go over the years from dropping
or
even just bumping them, (the cage keeps the glass from breaking,
usually,
but the filament goes anyway) I finally discovered an improvement. NJ
is
currently offering an instant rebate on compact fluorescent "bulbs".
These
are really cheap right now, so I put one in my droplight the other day
while
looking for a new bulb. Works fine, stays very cool (which is always
an
advantage under the car with the light next to your head), and gives
100W
equivalent light. I haven't dropped it yet, but I suspect that it
will be
a
lot more robust. Sure a lot cheaper than the ruggedized "drop light
bulbs"
they sell for this application (which are not a lot more rugged than
ordinary bulbs, in my experience.

That's funny. I've always used "rough service" type bulbs and have had
excellent luck with them, even when dropping. The only negative I've
experienced with them is that the bulb darkens considerably as the
filament
evaporates and deposits on the inside of the bulb. Mine usually die
from
old age, and by then I'm happy to see them gone because the light I'm
getting is quite poor. Thanks for the tip on the fluorescent light,
though. I do prefer the nice, white (and cool) light they provide.

Harold

I also use rough service bulbs that are dipped in some sort of
translucent rubber like material... they don't shatter when/if they get
splashed. I've also had excellent life spans with them.

I've also drilled two holes in the reflector, and installed two short
1/4-20 bolts from the inside out, with nylock nuts on the outside that
act as 'anti roll' feet.

My droplight will lie stable on it's back or either side. A most handy
modification.

I can put up a dropbox photo if anyone's interested.

Erik


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I found the early CF bulbs had rather lousy spectral characteristics and
also lousy ballasts. The more recent ones have a much better output
spectrum and the high frequency ballasts are much better, no flicker or
problems with strobe effect.

Halogen lighting is nominally about 3,200 degrees kelvin color
temperature and daylight is typically considered at around 5,500 degrees
(that varies a bit or course). It's a little more complicated than just
color temperature though it's also a function of the output spectrum.
Fluorescent lights, particularly the older ones, emit light at a few
specific wavelengths where halogen and incandescent emit across a much
wider spectrum. Even if the apparent color temperature is the same the
light may not look the same due to missing wavelengths.

The newer CF lamps have much better phosphor blends and fill in many of
those gaps. The earlier fluorescents were particularly heavy on some
green wavelengths. They now have fluorescents with specifically blended
phosphors that have strong red, green and blue output bands to match the
needs of video lighting use. Replacing 20kw of halogen studio lighting
with 5kw of fluorescent is a big power savings on the lighting alone and
also on greatly reduced air conditioning costs.

I find the best way to select the CF lamps is to look at them in the
operating display most stores seem to have to get an idea of what they
look like and then bring the one that looks best home for testing.

The human eye can do some very interesting color balancing so it is more
important to keep the lighting in a given area consistent that to have
it a specific color temperature. If you want a good test of this
balancing ability, try looking into a video camera with a B&W viewfinder
for 10 min or so while keeping your other eye open. You'll find the the
eye that has been in the viewfinder sees it as "real" black and white
while if you look at it with your other eye it appears blue and white.

The only things I find that takes a little getting used to is the 1/4
second or so turn on delay and the minute or two to come up to full
brightness. I have several 42w CF lamps in the cheap spring clamp
reflector shades that have replaced the 500w halogen floodlights as work
lights for many projects.

Pete C.



Shawn wrote:

Recently our local power company has been recommending replacing
incandescent bulbs with compact flourescent for energy savings. I've found
that the color of these are rather harsh and that the colors also vary from
one manufacturer to another. Sometimes the color temperature is listed on
the package but without something to reference it to, it is worthless to me.
What is the color temperature of a standard incandescent? Better yet, I
like the color of halogen bulbs, where do they fall?

Thanks,

Shawn

In article , Harold & Susan Vordos says...

Damned good idea! Nothing irritates me more than my light turning over when
I'm under a car and can't reach it easily. Needless to say, it's always
pointing in the wrong direction. ....

Translation: 'directly *away* from what I'm working on, and
directly *at* my eyes!!'

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

"jim rozen" wrote in message
...
In article , Harold & Susan Vordos says...

Damned good idea! Nothing irritates me more than my light turning over
when
I'm under a car and can't reach it easily. Needless to say, it's always
pointing in the wrong direction. ....

Translation: 'directly *away* from what I'm working on, and
directly *at* my eyes!!'

Jim

Chuckle!

So that was you under there. Couldn't tell. Light was in my eyes.

Harold

Thanks!

Shawn

Now is the time to start looking seriously at LEDs.

Ted

"Ted Edwards" wrote in message
...
Now is the time to start looking seriously at LEDs.

Ted
Yep! I just ordered my first LED flashlight.

Harold

Check out the LED lights at Costco. 1 watt if I remember correctly.
Karl

"Harold & Susan Vordos" wrote in message
...

"Ted Edwards" wrote in message
...
Now is the time to start looking seriously at LEDs.

Ted
Yep! I just ordered my first LED flashlight.

Harold




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On Sun, 05 Dec 2004 13:53:46 GMT, "Karl Vorwerk"
calmly ranted:

Check out the LED lights at Costco. 1 watt if I remember correctly.

Are those new, Karl? They're not listed on the website at all.
(Nothing in the search for "flashlight", printer parts and a
"mood light" under the search for "LED".)


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"Larry Jaques" wrote in message
...
On Sun, 05 Dec 2004 13:53:46 GMT, "Karl Vorwerk"
calmly ranted:

Check out the LED lights at Costco. 1 watt if I remember correctly.

Are those new, Karl? They're not listed on the website at all.
(Nothing in the search for "flashlight", printer parts and a
"mood light" under the search for "LED".)

Not everything that stores carry are on the web page. Stock even differs
between stores I've found in the past.

Lane

Larry Jaques wrote:

On Sun, 05 Dec 2004 13:53:46 GMT, "Karl Vorwerk"
calmly ranted:


Check out the LED lights at Costco. 1 watt if I remember correctly.


Are those new, Karl? They're not listed on the website at all.
(Nothing in the search for "flashlight", printer parts and a
"mood light" under the search for "LED".)


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I saw them - two in a package. Uses two double A's.
Martin

--
Martin Eastburn, Barbara Eastburn
@ home at Lion's Lair with our computer
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder

First time I've seen them. I bought the Streamlight 4AA LED light there
several months ago or I would have bought them. I just saw the new improved
Leatherman Wave at Home Depot for $60.
Karl

"Larry Jaques" wrote in message
...
On Sun, 05 Dec 2004 13:53:46 GMT, "Karl Vorwerk"
calmly ranted:

Check out the LED lights at Costco. 1 watt if I remember correctly.

Are those new, Karl? They're not listed on the website at all.
(Nothing in the search for "flashlight", printer parts and a
"mood light" under the search for "LED".)


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The use of a flourescent bulb also probably removes a danger that most
people would never consider. A fella I went to college with changed
trades after becoming a Tool and Die maker, and set to work as an
automotive mechanic. One day, while he had a car up on a hoist,
searching for a fuel leak, his trouble light fell, and the exposed
filament was engergized long enough to ignite the small amount of fuel
present. It wasn't much fuel, but because it was spread over a fairly
large area, it was a big enough fire to burn him pretty badly. He's fine
now, but it could have been much worse.


--
__
Pete Snell
Royal Military College
Kingston Ontario


The reasonable man adapts himself to the world;
the unreasonable one persists in trying to adapt the world to himself.
Therefore all progress depends on the unreasonable man.
- George Bernard Shaw

"Peter Snell" wrote in message
...
The use of a flourescent bulb also probably removes a danger that most
people would never consider. A fella I went to college with changed
trades after becoming a Tool and Die maker, and set to work as an
automotive mechanic. One day, while he had a car up on a hoist,
searching for a fuel leak, his trouble light fell, and the exposed
filament was engergized long enough to ignite the small amount of fuel
present. It wasn't much fuel, but because it was spread over a fairly
large area, it was a big enough fire to burn him pretty badly. He's fine
now, but it could have been much worse.

Indeed! I also don't much enjoy using an incandescent light for working
inside a vehicle. Damned things have a way of melting all kinds of plastics,
and they're really hard on skin when you happen to lean on them.

H

On Fri, 3 Dec 2004 10:48:26 -0500, "Bob Chilcoat"
vaguely proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

Funny! I was going to post almost exactly this post, yesterday! I had
the same experience. I dropped one of thses things and to my amazement
it kept working.

They have every advantage. Cool, low power, robust. Not quite cheap
here yet, but getting better. Well worth the dough.

I actually posted here asking about 12v - 240v inverters, because I
was going to be working outside. These fluoro's are ideal. I can run
6, maybe 7 "100W equivalents" off a 150W inverter, cost about $50. And
get quite a few hours out of a well-charged 12V battery. No fire
hazard if I drop one. Also a reflector can be any old piece of white
plastic and when I switch off, I can handle the thing straight away.

I now have 6 on camera tripods. Great for the BBQ as well.

Duck's nuts!

Having had many, many droplight bulbs go over the years from dropping or
even just bumping them, (the cage keeps the glass from breaking, usually,
but the filament goes anyway) I finally discovered an improvement. NJ is
currently offering an instant rebate on compact fluorescent "bulbs". These
are really cheap right now, so I put one in my droplight the other day while
looking for a new bulb. Works fine, stays very cool (which is always an

This thread is old so probably dead -- but ask Jerry Martes how he
likes his 1-watt Luxeon LED floodlight he received today. Eric
Snow will probably be making one like it pretty soon. These are the
ones using a 35-cent lens from AxMan surplus. Not as much light
as from a fluorescent, but the lamphead is only 1" dia x 1" deep and
it can illuminate everything hands can reach with enough light to read
fine print. It won't break if you drop it. "Lamp" life is 50,000
hours. It cost under $10, plus a bit of machining. It would cost
more than that for entry dues because of minimum order and set
exorbitant shipping charges from Future, the sole distributor of
Luxeons. The lux was $6.50, the lens was 35 cents. Batteries and
dropping resistor are left as an exercise.

On Fri, 3 Dec 2004 10:48:26 -0500, "Bob Chilcoat"
wrote:

Having had many, many droplight bulbs go over the years from dropping or
even just bumping them, (the cage keeps the glass from breaking, usually,
but the filament goes anyway) I finally discovered an improvement. NJ is
currently offering an instant rebate on compact fluorescent "bulbs". These
are really cheap right now, so I put one in my droplight the other day while
looking for a new bulb. Works fine, stays very cool (which is always an
advantage under the car with the light next to your head), and gives 100W
equivalent light. I haven't dropped it yet, but I suspect that it will be a
lot more robust. Sure a lot cheaper than the ruggedized "drop light bulbs"
they sell for this application (which are not a lot more rugged than
ordinary bulbs, in my experience.

Metal content: (1) The cage on mine is made of metal. (2) The cars I work
on with it are mostly metal. :-)

One thing to keep in mind is the size of the fluorescent
bulb. I have found that the higher wattage bulbs can be
larger than the "equivalent wattage" incandescent. I have
had them be either too long or too large in diameter to fit
some reflectors or cages. And they don't drop too well when
they're in contact with the cage!!!
I've found that they work well in my swing arm lamp on the
drill press and mill.
By the way, does anyone know if the bulb type florescence
will create a strobing effect like the old ballast and tube
types do?

In article , nic "user wrote:
One thing to keep in mind is the size of the fluorescent
bulb. I have found that the higher wattage bulbs can be
larger than the "equivalent wattage" incandescent. I have
had them be either too long or too large in diameter to fit
some reflectors or cages. And they don't drop too well when
they're in contact with the cage!!!
I've found that they work well in my swing arm lamp on the
drill press and mill.
By the way, does anyone know if the bulb type florescence
will create a strobing effect like the old ballast and tube
types do?

The ones which I have taken apart (after failure) have a printed
circuit board hosting a high frequency inverter to ionize them, instead
of depending on filaments to start the ionization. So -- the variation
in ionization will probably be too fast to show up relative to the decay
time of the phosphor.

But the thing to do, for any given lamp. is to test it. A
variable speed drill motor with a Jacobs style keyed chuck should
suffice. Vary the speed and watch for the pattern of the gear teeth
slowing down or standing still.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
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In article ,
says...
In article , nic "user wrote:
One thing to keep in mind is the size of the fluorescent
bulb. I have found that the higher wattage bulbs can be
larger than the "equivalent wattage" incandescent. I have
had them be either too long or too large in diameter to fit
some reflectors or cages. And they don't drop too well when
they're in contact with the cage!!!
I've found that they work well in my swing arm lamp on the
drill press and mill.
By the way, does anyone know if the bulb type florescence
will create a strobing effect like the old ballast and tube
types do?

The ones which I have taken apart (after failure) have a printed
circuit board hosting a high frequency inverter to ionize them, instead
of depending on filaments to start the ionization. So -- the variation
in ionization will probably be too fast to show up relative to the decay
time of the phosphor.


The compact fluorescents with electronic ballasts typically run in the
tens of kHz range. Surprisingly, the phoshpor is not persistent enough
to smooth out the peaks. I was able to measure the frequency of several
lamps with a phototube and scope. This was working on an illuminator for
a high speed machine vision application. With very short exposures it
was possible for the vision system to get confused if the exposure did
not average enough on-off cycles of the lamp.

CFs with replaceable lamps usually have magnetic ballasts, I don't know
why.

Ned Simmons

In article ,
Ned Simmons wrote:
In article ,
says...

[ ... ]

The ones which I have taken apart (after failure) have a printed
circuit board hosting a high frequency inverter to ionize them, instead
of depending on filaments to start the ionization. So -- the variation
in ionization will probably be too fast to show up relative to the decay
time of the phosphor.


The compact fluorescents with electronic ballasts typically run in the
tens of kHz range. Surprisingly, the phoshpor is not persistent enough
to smooth out the peaks. I was able to measure the frequency of several
lamps with a phototube and scope.

Hmm ... are you sure that you weren't seeing ultraviolet coming
through the phosphors. The UV is what excites the filters, and you
might try a low-pass filter (say red or orange) to see what it looks
like on the scope. If that looks smooth, perhaps the next step would be
to get a tunable optical filter (like a B&L Monochrometer) and check on
the other side of the tuned filter to see just where you get the ripple.

This was working on an illuminator for
a high speed machine vision application. With very short exposures it
was possible for the vision system to get confused if the exposure did
not average enough on-off cycles of the lamp.

Was the system sensitive to UV? Perhaps a haze filter would
have helped.

CFs with replaceable lamps usually have magnetic ballasts, I don't know
why.

Hmm ... not all of them. Some of those "monkey's fist" coils of
tubes plug in.

Enjoy,
DoN.

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In article , DoN. Nichols says...

Hmm ... are you sure that you weren't seeing ultraviolet coming
through the phosphors.

This is not possible - the major component of the mercury line is
at 254 nm, which is way too short to be passed by the glass tube.
Also the phosphors are completely opaque at those frequencies,
because the coatings are engineered to absorb all of the UV and
convert them into visible light. Any UV that gets past the
phosphor layer and absorbed by the glass will reduce the lamp's
efficiency.

Lighting phosphors have very short persistence. Long persistence
phosphors imply a metastable trap state in the system - and those
tend to be likewise be pretty lossy.

Probably what he was seeing was the response of the actual phosphor.

Jim


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In article ,
jim rozen wrote:
In article , DoN. Nichols says...

Hmm ... are you sure that you weren't seeing ultraviolet coming
through the phosphors.

This is not possible - the major component of the mercury line is
at 254 nm, which is way too short to be passed by the glass tube.
Also the phosphors are completely opaque at those frequencies,

Hmm ... the phosphors are sufficiently scattered so *visible*
light goes through with little problem -- just hold a flashlight behind
one to prove this. I doubt that there is sufficient density in the
phosphor coating to block the UV when it is so sparse in the visible.

because the coatings are engineered to absorb all of the UV and
convert them into visible light. Any UV that gets past the
phosphor layer and absorbed by the glass will reduce the lamp's
efficiency.

O.K. But I still have my doubts. I guess that the UV lamps in
the same form factor as the standard fluorescents is quartz glass.

Lighting phosphors have very short persistence. Long persistence
phosphors imply a metastable trap state in the system - and those
tend to be likewise be pretty lossy.

O.K. Scope phosphors tend to be selected for long decay times.
The same for CRTs for terminals with green or amber displays, while TV
CRTs tend to have rather fast decays -- as needed because of the
frequent changes. Obviously, the white phosphor terminals are using TV
CRTs for economy purposes.

Probably what he was seeing was the response of the actual phosphor.

Perhaps, though I still suspect UV penetration, even if somewhat
attenuated by absorption in the (quite thin) glass walls.

Enjoy,
DoN.

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Hmm ... are you sure that you weren't seeing ultraviolet coming
through the phosphors.

This is not possible - the major component of the mercury line is
at 254 nm, which is way too short to be passed by the glass tube.
Also the phosphors are completely opaque at those frequencies,

Hmm ... the phosphors are sufficiently scattered so *visible*
light goes through with little problem -- just hold a flashlight
behind
one to prove this. I doubt that there is sufficient density in the
phosphor coating to block the UV when it is so sparse in the visible.

Don't forget that an ideal phosphor would be opaque in the UV and
transparent in the visible. If it's not tranparent, it can reabsorb the
visible photons and efficiency goes down. That means the flashlight can
shine through, and also the visible lines from the mercury even if the
UV is blocked. If you look at typcial spectra for fluorescent lamps
(see sylvania.com, for example), the output is a mix of the phoshpor
output plus the mercury lines that fall in the visible, so without some
kind of filter or monochromator your phototube had to be reacting to
both.

--
Regards,
Carl Ijames carl.ijames at verizon.net

In article , DoN. Nichols says...

Perhaps, though I still suspect UV penetration, even if somewhat
attenuated by absorption in the (quite thin) glass walls.

Even a very thin layer of the glass of the type used for
lamp envelopes will completely cut off any 254 nm radiation.

But the glass never sees this, it's all absorbed completely
by the phosphor. IOW if you could 'see' in the 254 nn UV
region, a smear of, say, cool-white phosphor on even a quartz
(suprasil) plate would still look like flat black paint.
Even though the quartz would allow UV to pass, even a very
thin layer of phospor absorbs the UV completely.

Phospors are quantum mechanical machines that gobble up
UV photons, and spit out visible ones. If they allowed
the higher energy photons to pass through, they would not
make good lighting equipment. :^)

Jim


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please reply to:
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In article ,
says...
In article ,
Ned Simmons wrote:
In article ,
says...

[ ... ]

The ones which I have taken apart (after failure) have a printed
circuit board hosting a high frequency inverter to ionize them, instead
of depending on filaments to start the ionization. So -- the variation
in ionization will probably be too fast to show up relative to the decay
time of the phosphor.


The compact fluorescents with electronic ballasts typically run in the
tens of kHz range. Surprisingly, the phoshpor is not persistent enough
to smooth out the peaks. I was able to measure the frequency of several
lamps with a phototube and scope.

Hmm ... are you sure that you weren't seeing ultraviolet coming
through the phosphors.

It seems unlikely. If that were the case I'd have expected to see a high
frequency ripple biased by the persistence of the phosphors. This was
several years ago, but my recollection is that the trace made a full
excursion.

This was working on an illuminator for
a high speed machine vision application. With very short exposures it
was possible for the vision system to get confused if the exposure did
not average enough on-off cycles of the lamp.

Was the system sensitive to UV? Perhaps a haze filter would
have helped.

The image sensor itself may have been, but any UV would have to have
passed thru not only the lamp phosphor and envelope, but about 2" of
acrylic, a 1/8" glass window, a 1/8" clear urethane belt, and finally
thru the the glass elements of the camera lens. Even acrylic optimized
for UV transmission passes very little at the wavelength Jim cited.

The illuminator backlit the parts under inspection (wooden clothespin
halves travelling at 15-20 feet/sec) and it was easy to see random
variations in the apparent brightness of the illuminator when the
exposure was short enough to include only a few peaks of the light.

Ned Simmons

In article , Ned Simmons
says...

The image sensor itself may have been, but any UV would have to have
passed thru not only the lamp phosphor and envelope, but about 2" of
acrylic, a 1/8" glass window, a 1/8" clear urethane belt, and finally
thru the the glass elements of the camera lens. Even acrylic optimized
for UV transmission passes very little at the wavelength Jim cited.

There are very few materials that pass 254 nm radiation, suprasil
quartz (quartz that has low OH radical concentration) being one
of them.

Basically if you want to see if anything passes UV light, illuminate
it with that wavelength and see if it fluoresces. If it does, it
is absorbing the incident radiation.

Jim


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Hey Guys,


Well, Season's Greetings to Everybody. I have to say it now, as we
will be away in California until the New Year.

Take care.

Brian Lawson,
Bothwell, Ontario.

On Mon, 13 Dec 2004 01:41:43 -0500, Brian Lawson
wrote:

Hey Guys,


Well, Season's Greetings to Everybody. I have to say it now, as we
will be away in California until the New Year.

Take care.

Brian Lawson,
Bothwell, Ontario.

Give me a call when you come out and come up to the house and visit~

805-732-5308

Ill let you dig though my Stuff G

Gunner

"To be civilized is to restrain the ability to commit mayhem.
To be incapable of committing mayhem is not the mark of the civilized,
merely the domesticated." - Trefor Thomas

"Brian Lawson" wrote in message
...
Hey Guys,


Well, Season's Greetings to Everybody. I have to say it now, as we
will be away in California until the New Year.

Take care.

Brian Lawson,
Bothwell, Ontario.

If you drive south on I-5 through Washington State, we'd love to have you
drop by. It's 14 miles out of your way from the freeway.

Harold

"Brian Lawson" wrote in message
...
Hey Guys,


Well, Season's Greetings to Everybody. I have to say it now, as we
will be away in California until the New Year.

Take care.

Brian Lawson,
Bothwell, Ontario.

And to you and yours, Brian. Don't let them put a ring in your ear while
you're in California. Those guys are trying to make everyone look like a
Colorado Spinner.

Ed Huntress

Brian Lawson wrote:
Hey Guys,


Well, Season's Greetings to Everybody. I have to say it now, as we
will be away in California until the New Year.

Take care.

Brian Lawson,
Bothwell, Ontario.

Welcome to California, Brian.

Remember as you cross the state line: Use your turn signals, go to jail.



--Winston