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Electron gun lightning.

I was just thinking about electron guns and how they could
theroretically staticly cherge metal they were aimed at. This gave me
an idea. If I hung a mylar balloon a few inches from the ground, from a
plastic insulative string, and shot an electron gun from a computer
monitor at it; would the ballon build up a negative charge and shoot a
lightning bolt to the ground?
 
D

DBLEXPOSURE

Jan 1, 1970
0
I was just thinking about electron guns and how they could
theroretically staticly cherge metal they were aimed at. This gave me
an idea. If I hung a mylar balloon a few inches from the ground, from a
plastic insulative string, and shot an electron gun from a computer
monitor at it; would the ballon build up a negative charge and shoot a
lightning bolt to the ground?

Lol

The can't theoretically charge metal they are aimed at. They only work when
they are aimed at a charge............

Here study up on how a CRT works and then tell us if you think your
experiment will work..

http://en.wikipedia.org/wiki/Cathode_ray_tube

http://inventors.about.com/library/inventors/blcathoderaytube.htm

http://www.chem.uiuc.edu/clcwebsite/cathode.html
 
J

John Larkin

Jan 1, 1970
0
Lol

The can't theoretically charge metal they are aimed at. They only work when
they are aimed at a charge............

Sure they can. Whack a hunk of metal with electrons, and it'll go
negative.

The trick would be to keep the balloon inflated in the vacuum you'd
need to keep this kind of electron gun working. There are electron
guns that can zot a beam through air, but that's a whole nother story.

John
 
D

DBLEXPOSURE

Jan 1, 1970
0
John Larkin said:
Sure they can. Whack a hunk of metal with electrons, and it'll go
negative.

The trick would be to keep the balloon inflated in the vacuum you'd
need to keep this kind of electron gun working. There are electron
guns that can zot a beam through air, but that's a whole nother story.

John

How are we going to "whack" this balloon with electrons?

I think he wants to do it outside the tube. Are we gonna cut a hole in the
face of the tube and run some clip leads from the anode to the balloon?
 
J

John Larkin

Jan 1, 1970
0
How are we going to "whack" this balloon with electrons?

I think he wants to do it outside the tube. Are we gonna cut a hole in the
face of the tube and run some clip leads from the anode to the balloon?

A regular CRT gun can't do this, as I think I noted. But there are
electron guns with thin windows, usually beryllium, that have vacuum
inside but let the beam escape into free air. It takes a pretty
powerful beam, as in 100's of kilovolts, to travel any useful distance
in air, but it is done, as for sterilizing foods and such.

If you banged a metallic object with such a beam, it would acquire
negative charge. And you'd maybe die from the incidental x-rays.

John
 
D

DBLEXPOSURE

Jan 1, 1970
0
John Larkin said:
A regular CRT gun can't do this, as I think I noted. But there are
electron guns with thin windows, usually beryllium, that have vacuum
inside but let the beam escape into free air. It takes a pretty
powerful beam, as in 100's of kilovolts, to travel any useful distance
in air, but it is done, as for sterilizing foods and such.

If you banged a metallic object with such a beam, it would acquire
negative charge. And you'd maybe die from the incidental x-rays.

John

Interesting, Sounds like momentum carries the beam past the anode? Perhaps
a deflection coil to keep the beam off the Anode?

I was thinking it might be easier for the OP to achieve his fireworks with a
magnetron and a parabolic reflector. If I had a hunk of mylar I'd throw it
in the microwave to see what happens....

Of couse there might be some dangerous radiation to worry about here as
well... Oh well, My kids are grown and wasent thinking of having anymore
anyway..
 
J

John Larkin

Jan 1, 1970
0
Interesting, Sounds like momentum carries the beam past the anode? Perhaps
a deflection coil to keep the beam off the Anode?

Usually the beryllium window *is* the anode. If the electrons are
going fast enough, most of them sail clean through, just slip berween
the Be nuclei. Beryllium is the common choice because it's light and
strong (a thin foil has to stand up to 15 psi differential) and the
nuclei are small. Electrons will also happily sail through an anode
with a hole in it, but then the vacuum would leak out.
I was thinking it might be easier for the OP to achieve his fireworks with a
magnetron and a parabolic reflector.

That wouldn't transfer charge.

John
 
D

DBLEXPOSURE

Jan 1, 1970
0
John Larkin said:
Usually the beryllium window *is* the anode. If the electrons are
going fast enough, most of them sail clean through, just slip berween
the Be nuclei. Beryllium is the common choice because it's light and
strong (a thin foil has to stand up to 15 psi differential) and the
nuclei are small. Electrons will also happily sail through an anode
with a hole in it, but then the vacuum would leak out.


That wouldn't transfer charge.

John

Okay, but most mylar balloons are "Alimunized Mylar" and perhaps with a
little manipulation of the balloon we might be able to get some sparks
going...
 
M

me

Jan 1, 1970
0
Sure they can. Whack a hunk of metal with electrons, and it'll go
negative.

only with respect to some potential reference. Whack it hard enough and
get bremstralung radiation...
 
At the time I wrote this I hadn't realized the the electrons could only
travel in a vacum, it was a mistake I regreted less than an hour later.
So... how about an ion-ray Gun?
 
D

DBLEXPOSURE

Jan 1, 1970
0
At the time I wrote this I hadn't realized the the electrons could only
travel in a vacum, it was a mistake I regreted less than an hour later.
So... how about an ion-ray Gun?

Electrons travel everywhere...

I believe CRT's receiving tubes, etc.. are evacuated is to keep impurities
out which would shorten the life of the cathode.
 
D

Don Bruder

Jan 1, 1970
0
DBLEXPOSURE said:
Electrons travel everywhere...

But they travel MUCH better in places where they aren't running into
things.
I believe CRT's receiving tubes, etc.. are evacuated is to keep impurities
out which would shorten the life of the cathode.

Tell ya what... Let's have you test that belief.

Let's do a simple cookbook-style experiment, shall we?

Open up your TV set, and pull the control board off the end of the
picture tube. Probably have to wiggle it a bit - they're usually pretty
tight.

In the middle of the ring of pins on the back of the tube, there's a
little tit of thin glass where they melted it shut after drawing down
the vacuum on it. Use a pair of needlenose pliers or similar to grab
that little tit and bend it until you feel it crack and you hear a hiss,
whistle, whoosh, or some similar "air in fast motion through small
opening" noise.

Once the noise stops, put the plug back on the tube - make sure you
match up the keyway - and fire that puppy up.

Report back on how well it works.

Hint: Before you go destroying your TV set, lemme save you some effort.
It ain't gonna work AT ALL. Electrons CAN travel through air in certain
situations (think lightning - Charge flowing through an ionized channel
of air), but not well. That's why air is generally considered an
insulator. An electron beam is either absorbed or scatttered into
uselessness by collisions with the atoms making up the air and/or any
particles that might be suspended in it.
 
D

DBLEXPOSURE

Jan 1, 1970
0
Don Bruder said:
But they travel MUCH better in places where they aren't running into
things.


Tell ya what... Let's have you test that belief.

Let's do a simple cookbook-style experiment, shall we?

Open up your TV set, and pull the control board off the end of the
picture tube. Probably have to wiggle it a bit - they're usually pretty
tight.

In the middle of the ring of pins on the back of the tube, there's a
little tit of thin glass where they melted it shut after drawing down
the vacuum on it. Use a pair of needlenose pliers or similar to grab
that little tit and bend it until you feel it crack and you hear a hiss,
whistle, whoosh, or some similar "air in fast motion through small
opening" noise.

Once the noise stops, put the plug back on the tube - make sure you
match up the keyway - and fire that puppy up.

Report back on how well it works.

Hint: Before you go destroying your TV set, lemme save you some effort.
It ain't gonna work AT ALL. Electrons CAN travel through air in certain
situations (think lightning - Charge flowing through an ionized channel
of air), but not well. That's why air is generally considered an
insulator. An electron beam is either absorbed or scatttered into
uselessness by collisions with the atoms making up the air and/or any
particles that might be suspended in it.

--
Don Bruder - [email protected] - New Email policy in effect as of Feb. 21,
2004.
Short form: I'm trashing EVERY E-mail that doesn't contain a password in
the
subject unless it comes from a "whitelisted" (pre-approved by me) address.
See <http://www.sonic.net/~dakidd/main/contact.html> for full details.

Geeze Don, why so sarcastic?



I said tubes are evacuated to keep impurities out, didn't feel like writing
a smart-ass sarcastic dissertation on the subject. Are you saying that
impurities will not affect the cathode?



Tubes get gasy quite often, they don't just quite working they die a slow
death. Degradation of the cathode plays a part in that death.



In your experiment I am sure quite a number of things would go wrong,
perhaps some arcing at the anode. Filaments might burn open. And if it
tried to make a picture it probably wouldn't be perfect or long lived. Have
you ever tried it?



Go buy two light bulbs, very carefully let the air out one. Now fire em
both up and see which one last longer.



I was responding to the "Electrons only travel in a vacuum comment" It is
simply not true. If it where my TV wouldn't need tube as I wouldn't be able
to receive any signal to display on it
 
J

Jasen Betts

Jan 1, 1970
0
I was just thinking about electron guns and how they could
theroretically staticly cherge metal they were aimed at. This gave me
an idea. If I hung a mylar balloon a few inches from the ground, from a
plastic insulative string, and shot an electron gun from a computer
monitor at it; would the ballon build up a negative charge and shoot a
lightning bolt to the ground?

no. the electron gun won't function in the atmosphere.

the voltage inside the computer monitor isn't enough to make a spark jump
more than an inch or two through the air.

however if you could get enough charge onto the balloon there would be a
spark to ground if the ground didn't attract the baloon to it frist :)

Bye.
Jasen
 
J

Jasen Betts

Jan 1, 1970
0
I was responding to the "Electrons only travel in a vacuum comment" It is
simply not true. If it where my TV wouldn't need tube as I wouldn't be able
to receive any signal to display on it

well, yeah, electrons travel through cables too :)

but my TV gets its signal from an antenna and radio waves aren't composed
of electrons. they're composed of photons.

Bye.
Jasen
 
D

DBLEXPOSURE

Jan 1, 1970
0
Jasen Betts said:
well, yeah, electrons travel through cables too :)

Yes, but I do not have cable TV. ANd even the I am certain that somewhere
along the line the signal was transmitted through through the air. i.e.
sattelite, microwave STL link, ENG truck, etc etc...
 
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