B
BretCahill
Guest
What is the basic problem in making compact flouercent flashlight bulbs?
Bret Cahill
Bret Cahill
P
Phil Hobbs
Guest
BretCahill wrote:
tube with anything like the surface brightness of a tungsten filament. The large
diffuse radiating surface means that you can't get any sort of beam from such a
bulb. Stick a couple of layers of Magic Invisible Tape on the bulb of an ordinary
flashlight to get an idea of what this does.
LEDS are a much better bet.
Cheers,
Phil Hobbs
Surface brightness. Due to limited phosphor lifetime, you can't make a fluorescent
tube with anything like the surface brightness of a tungsten filament. The large
diffuse radiating surface means that you can't get any sort of beam from such a
bulb. Stick a couple of layers of Magic Invisible Tape on the bulb of an ordinary
flashlight to get an idea of what this does.
LEDS are a much better bet.
Cheers,
Phil Hobbs
M
Mike Harrison
Guest
On Wed, 24 Sep 2003 13:05:19 -0400, Phil Hobbs <pcdh@SpamMeSenseless.us.ibm.com> wrote:
http://ledmuseum.home.att.net/lc100.htm
....Although a HID flashlight does exist :
http://ledmuseum.home.att.net/lc100.htm
P
Phil Hobbs
Guest
Mike Harrison wrote:
Searchlights, for example.
That looks like a great flashlight, but I wouldn't want to try finding bulbs at
Walmart.
Cheers,
Phil Hobbs
Right, arc lamps have much higher surface brightness than tungsten, even.
Searchlights, for example.
That looks like a great flashlight, but I wouldn't want to try finding bulbs at
Walmart.
Cheers,
Phil Hobbs
B
BretCahill
Guest
don@manx.misty.com (Don Klipstein) in
be just one problem: a lot of volume is
required for efficient flourescent lights.
area?
8 - 10 inches in diameter?
Bret Cahill
Short length and small diameter seem to
be just one problem: a lot of volume is
required for efficient flourescent lights.
There isn't any way to increase the surface
area?
Why not use a really big reflector -- about
8 - 10 inches in diameter?
Bret Cahill
D
Don Klipstein
Guest
In article <20030924130115.03086.00000143@mb-m07.aol.com>, BretCahill wrote:
1. The voltage drop per centimeter of discharge length is low. Unless
the discharge path is at least a few centimeters long, most of the voltage
drop across the lamp will be electrode losses.
2. There is an optimum diameter for fluorescent lamps, and their
efficiency decreases when you go below a couple centimeters and decreases
a lot when you go below several millimeters in diameter.
3. When the "electron temperature" (average kinetic energy of free
electrons, expressed in temperature terms) is best for producing mercury's
shortwave ultraviolet wavelengths that make fluorescent lamps work (as
opposed to other UV wavelengths, infrared, and infrared wavelengths from
the argon also present, etc.) it is a limitation on how much UV the
mercury can produce. You cannot exceed the same amount of UV in that
spectral feature's bandwidth radiated by the same area of radiating
surface of a blackbosy whose temperature matches the "electron
temperature" in question. So you cannot get fluorescent lamps with the
surface brightness of incandescents, LED chips, etc.
- Don Klipstein (don@misty.com, http://www.misty.com/~don/dschtech.html)
Three problems:
1. The voltage drop per centimeter of discharge length is low. Unless
the discharge path is at least a few centimeters long, most of the voltage
drop across the lamp will be electrode losses.
2. There is an optimum diameter for fluorescent lamps, and their
efficiency decreases when you go below a couple centimeters and decreases
a lot when you go below several millimeters in diameter.
3. When the "electron temperature" (average kinetic energy of free
electrons, expressed in temperature terms) is best for producing mercury's
shortwave ultraviolet wavelengths that make fluorescent lamps work (as
opposed to other UV wavelengths, infrared, and infrared wavelengths from
the argon also present, etc.) it is a limitation on how much UV the
mercury can produce. You cannot exceed the same amount of UV in that
spectral feature's bandwidth radiated by the same area of radiating
surface of a blackbosy whose temperature matches the "electron
temperature" in question. So you cannot get fluorescent lamps with the
surface brightness of incandescents, LED chips, etc.
- Don Klipstein (don@misty.com, http://www.misty.com/~don/dschtech.html)
P
Phil Hobbs
Guest
BretCahill wrote:
bright mercury arcs, it's just that the phosphor toasts almost instantly
if you go above a certain limiting flux level. This is why compact FLs
are long twisted tubes and not spherical globes.
cm/steradian.
Yes, of course, if you collect all the light from the bulb and image it
on the wall, you can get a surface illuminance of 1/M**2 times the
bulb's surface illuminance, where M is the magnification. Assuming you
don't lose any, which is a fairly heroic assumption.
That isn't my idea of a flashlight, but don't take my word for it. Why
don't you build it, and see how well it sells?
Cheers,
Phil Hobbs
No, it really is a surface issue. There's no problem building _very_
bright mercury arcs, it's just that the phosphor toasts almost instantly
if you go above a certain limiting flux level. This is why compact FLs
are long twisted tubes and not spherical globes.
The area isn't the issue--it's the surface brightness in lumens/square
cm/steradian.
Yes, of course, if you collect all the light from the bulb and image it
on the wall, you can get a surface illuminance of 1/M**2 times the
bulb's surface illuminance, where M is the magnification. Assuming you
don't lose any, which is a fairly heroic assumption.
That isn't my idea of a flashlight, but don't take my word for it. Why
don't you build it, and see how well it sells?
Cheers,
Phil Hobbs
W
Watson A.Name - "Watt Sun
Guest
In article <20030924130115.03086.00000143@mb-m07.aol.com>,
bretcahill@aol.com mentioned...
or below freezing. Fluorescents have been in use for exterior
lighting for a long time here in So Calif, but then it doesn't get
that cold.
Another problem is that the light output is spread out over a large
area, so it's difficult to concentrate it into a beam. But I've got a
Burgess portable fluo light that's from the '60s, and uses lantern
batteries or an electric power cord. I couldn't afford to buy
batteries for it, so I've always used it on the power cord. It has a
short 15"(?) tube at the focal point of a chrome sheet for a
reflector, to help direct the light to the front. But it's nowhere
near as bright as a regular flashlight. Burgess - remember those
batteries?
)
If you want to know just about everything about lighting, check out
Don Klipstein's web pages. http://members.misty.com/don/light.html
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
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My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
bretcahill@aol.com mentioned...
One problem is that they don't put out much light at temps near
or below freezing. Fluorescents have been in use for exterior
lighting for a long time here in So Calif, but then it doesn't get
that cold.
Another problem is that the light output is spread out over a large
area, so it's difficult to concentrate it into a beam. But I've got a
Burgess portable fluo light that's from the '60s, and uses lantern
batteries or an electric power cord. I couldn't afford to buy
batteries for it, so I've always used it on the power cord. It has a
short 15"(?) tube at the focal point of a chrome sheet for a
reflector, to help direct the light to the front. But it's nowhere
near as bright as a regular flashlight. Burgess - remember those
batteries?
)If you want to know just about everything about lighting, check out
Don Klipstein's web pages. http://members.misty.com/don/light.html
--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
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My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
W
Watson A.Name - "Watt Sun
Guest
In article <3F71CECF.2F5F15F4@SpamMeSenseless.us.ibm.com>,
pcdh@SpamMeSenseless.us.ibm.com mentioned...
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
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My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
pcdh@SpamMeSenseless.us.ibm.com mentioned...
Much better bet for what?
--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
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My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
R
Richard Crowley
Guest
"Watson A.Name - Watt Sun" wrote ...
Light production for a given size.
W
Watson A.Name - "Watt Sun
Guest
In article <20030924210726.27155.00000134@mb-m03.aol.com>,
bretcahill@aol.com mentioned...
and be dissipated as heat?
--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
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My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
bretcahill@aol.com mentioned...
Well, where's the light going to go? Right back into its own surface
and be dissipated as heat?
--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
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My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
J
JeffM
Guest
The way a flourescent light works is very obvious
once you strip off the phosphor layer inside the bulb.
You then have what was very common in head shops and nightclubs years ago
--a black light.
The ultraviolet light produced by the mercury-vapor lamp
is absorbed by the phosphors and re-radiated as visible light.
The phosphors can only absorb so much energy without being destroyed.
That's kinda like trying to cook a turkey at 650 degrees for 2 hours
instead of 325 degrees for 4 hours.
once you strip off the phosphor layer inside the bulb.
You then have what was very common in head shops and nightclubs years ago
--a black light.
The ultraviolet light produced by the mercury-vapor lamp
is absorbed by the phosphors and re-radiated as visible light.
The phosphors can only absorb so much energy without being destroyed.
That's kinda like trying to cook a turkey at 650 degrees for 2 hours
instead of 325 degrees for 4 hours.
B
BretCahill
Guest
Watson A.Name - "Watt Sun" <alondra101@hotmail.com> in
momentum transfer & forgot all about
fields.
Pretty funny now that I think about it.
around the curved or pleated surfaces and
away from the tube.
I don't immediately see what would
preclude that or other tactics.
Bret Cahill
.. . .
Ooops. Spent too much time in heat and
momentum transfer & forgot all about
fields.
Pretty funny now that I think about it.
Use lenses or reflectors to get the light
around the curved or pleated surfaces and
away from the tube.
I don't immediately see what would
preclude that or other tactics.
Bret Cahill
W
Watson A.Name - "Watt Sun
Guest
In article <vn4tboa9o585d7@corp.supernews.com>, rcrowley7@xprt.net
mentioned...
_less_ efficient than fluorescent lights. See Don Klipstein's LED
pages for more info on this. http://members.misty.com/don/ledx.html
--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
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My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
mentioned...
They're not any better efficiency than halogen bulbs, which are much
_less_ efficient than fluorescent lights. See Don Klipstein's LED
pages for more info on this. http://members.misty.com/don/ledx.html
--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
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My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
W
Watson A.Name - "Watt Sun
Guest
In article <f8b945bc.0309242359.5a2819ca@posting.google.com>,
jeffm_@email.com mentioned...
only an hour or so. Why didn't someone think of that low tech
solution years ago? Or did it just go out of style for decades, then
suddenly come back?
--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
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My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
jeffm_@email.com mentioned...
Ooh, charcoal! Now the trend is to deep fry the turkey outside in
only an hour or so. Why didn't someone think of that low tech
solution years ago? Or did it just go out of style for decades, then
suddenly come back?
--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
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My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
W
Watson A.Name - "Watt Sun
Guest
In article <20030925040741.14483.00000208@mb-m28.aol.com>,
bretcahill@aol.com mentioned...
buying a couple screw-in fluo replacement bulbs for five bucke each,
but decided against it, figuring that they were half the regular price
because they were half as good and lasted half as long, or maybe less.
These were three inverted U tubes, the other brands were the kind with
the tube in a spiral or screw thread shape. I thought, what happens
to all the light that is on the inside of inverted Us or the screw
thread? I would guess that a lot of it doesn't make it out, but gets
wasted as heat when it hits the other parts of the bulb. But it still
beats an incandescent bulb!
--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
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My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
bretcahill@aol.com mentioned...
I was over at the Big Orange Box store the other day and thought about
buying a couple screw-in fluo replacement bulbs for five bucke each,
but decided against it, figuring that they were half the regular price
because they were half as good and lasted half as long, or maybe less.
These were three inverted U tubes, the other brands were the kind with
the tube in a spiral or screw thread shape. I thought, what happens
to all the light that is on the inside of inverted Us or the screw
thread? I would guess that a lot of it doesn't make it out, but gets
wasted as heat when it hits the other parts of the bulb. But it still
beats an incandescent bulb!
--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
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My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
R
Richard Crowley
Guest
"Watson A.Name - Watt Sun" <alondra101@hotmail.com> wrote in message
news:MPG.19dc44894700ee48989706@news.dslextreme.com...
news:MPG.19dc44894700ee48989706@news.dslextreme.com...
But aren't they more rugged and long-lasting?
B
BretCahill
Guest
Watson A.Name - "Watt Sun" <alondra101@hotmail.com> in
grease?
Bret Cahill
.. . .
In politics that's call "good reasoning."
They couldn't justify using that much
grease?
Bret Cahill
L
Lizard Blizzard
Guest
Richard Crowley wrote:
not cheap.
--
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Incorrect uses: (i) the apostrophe must not be used with a plural
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(ii) there is no such word as ~her's, our's, their's, your's~.
Confusions: it's = it is or it has (not 'belonging to it'); correct
uses are ~it's here~ (= it is here); ~it's gone~ (= it has gone);
but ~the dog wagged its tail~ (no apostrophe).
----------------(For the Apostrophe challenged)----------------
From a fully deputized officer of the Apostrophe Police!
<<Spammers use Weapons of Mass Distraction!>>
I bought some batteries, but they weren't included,
so I had to buy them again.
-- Steven Wright
FOR SALE: Nice parachute: never opened - used once.
(Problem) Evidence of leak on right main landing gear
(Solution) Evidence removed
F
o
d
d
e
r
f
o
r
s
t
u
p
i
d
"
n
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t
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t
"
e
r
r
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m
s
g
..
Cost is a big factor, too. Perhaps the biggest factor. And LEDs are
not cheap.
--
----------------(from OED Mini-Dictionary)-----------------
PUNCTUATION - Apostrophe
Incorrect uses: (i) the apostrophe must not be used with a plural
where there is no possessive sense, as in ~tea's are served here~;
(ii) there is no such word as ~her's, our's, their's, your's~.
Confusions: it's = it is or it has (not 'belonging to it'); correct
uses are ~it's here~ (= it is here); ~it's gone~ (= it has gone);
but ~the dog wagged its tail~ (no apostrophe).
----------------(For the Apostrophe challenged)----------------
From a fully deputized officer of the Apostrophe Police!
<<Spammers use Weapons of Mass Distraction!>>
I bought some batteries, but they weren't included,
so I had to buy them again.
-- Steven Wright
FOR SALE: Nice parachute: never opened - used once.
(Problem) Evidence of leak on right main landing gear
(Solution) Evidence removed
F
o
d
d
e
r
f
o
r
s
t
u
p
i
d
"
n
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Thinker
Guest
"BretCahill" <bretcahill@aol.com> wrote in message
news:20030924210726.27155.00000134@mb-m03.aol.com...
Then it would not be compact anymore!
news:20030924210726.27155.00000134@mb-m03.aol.com...
Then it would not be compact anymore!