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Light a bulb without a closed circuit

I was recently reading a paper about charges on the surface of circuit
elements, and how circuits settle to a stead-state of charge flow.
They mentioned in passing an experiment I have never seen, and I was
wondering if anyone here has heard of it:

They mentioned that they could light a bulb in a non-closed circuit,
by connecting one end to a battery and a bulb. Obviosuly it was not
usign a group loop or external induction, but was meant to be setup in
a way that the small transient could actually be seen. They even had
it so that if you bent the wire you could make bulbs light up because
you would be temporarily causing non-uniform charge areas that have to
flow to steady state (no current). Does anyone know specifically what
they did?

The only ones I have seen are where you put a capacitor and a globe in
a series circuit and connect it to a battery and make the globe light
when you move the bulb/wires close to the battery.
 
M

Martin Brown

Jan 1, 1970
0
Jan said:
Any neon will do it, stick one end in the mains, long piece of not connected
wire on the other side, or series resistor of a MOhm and touch it.
In RF environments you need no wires at all with neon bulbs.

More impressive still vertical fluorescent tubes will glow quite nicely
when you pass under an EHT power line. There was a nice art installation
of hundreds of them plonked in a field under supergrid pylons a few
years back in the UK. Made the front page of several papers.

Regards,
Martin Brown
 
W

whit3rd

Jan 1, 1970
0
They mentioned that they could light a bulb in a non-closed circuit,

With RF, it's easy. Put a dead fluorescent lamp in your microwave
oven next time you heat up the coffee, or connect rabbit-ear
antennae to an incandescent lamp and stand next to a
transmitter.
 
T

Tim Williams

Jan 1, 1970
0
With RF, it's easy.  Put a dead fluorescent lamp in your microwave
oven next time you heat up the coffee, or connect rabbit-ear
antennae to an incandescent lamp and stand next to a
transmitter.

Of course, all of these phenomena can be analyzed under normal rules
when you include parasitic capacitance to ground, which can be empty
space if nothing else; for instance, as I recall the Earth is around
1uF simply by being a conductive sphere.

Tim
 
Z

ZACK`

Jan 1, 1970
0
Martin Brown said:
More impressive still vertical fluorescent tubes will glow quite nicely
when you pass under an EHT power line. There was a nice art installation
of hundreds of them plonked in a field under supergrid pylons a few years
back in the UK. Made the front page of several papers.

Regards,
Martin Brown

you can light a up a dead fluo tube say 40watt with a
car ignition coil by osillating it like ccfs
 
M

Martin Brown

Jan 1, 1970
0
ZACK` said:
you can light a up a dead fluo tube say 40watt with a
car ignition coil by osillating it like ccfs

It is more fun if the ignition coil is used to drive a Tesla coil - then
you really can get some interesting illumination effects from vacuum tubes.

Regards,
Martin Brown
 
M

MisterE

Jan 1, 1970
0
Yes, volts per meter.
If the HV line is for example 100 kV, and 25 meters high, then you have 4
kV
per meter.
That should give 4 kV over the length of a 1 meter long vertical
fluorescent,
enough to trigger ionisation.

The experiment I was refering to was able to capture the slight current that
is caused when you connect a peice of metal to a potential, there was no
voltage 'field' involved.
 
M

MisterE

Jan 1, 1970
0
With RF, it's easy. Put a dead fluorescent lamp in your microwave
oven next time you heat up the coffee, or connect rabbit-ear
antennae to an incandescent lamp and stand next to a
transmitter.

No it was without any sort of induction or field, it was purely by capturing
the tiny movement of very small amount of charge in a wire when you connect
it to any voltage, like how you can measure static electric field that is
different in different parts of the same circuit, as charge accumulates
unevenely even at steady state.
 
W

whit3rd

Jan 1, 1970
0
No it was without any sort of induction or field, it was purely by capturing
the tiny movement of very small amount of charge in a wire when you connect
it to any voltage, like how you can measure static electric field that is
different in different parts of the same circuit, as charge accumulates
unevenely even at steady state.

I'm not sure what that means. There is an old experimental technique
using a 'ballistic galvanometer' that can capture charge transfer
on contact (like when your shoes rub the carpet and a static
charge transfers). There are very real fields involved there, of
course.
All material objects generate and shape electric fields.

"small amount of charge in a wire when you connect it" could cover
ANY kind of electric light.
 
W

whit3rd

Jan 1, 1970
0
Of course, all of these phenomena can be analyzed under normal rules
when you include parasitic capacitance to ground

Not all. To explain radiation (like, electric energy more than one
wavelength away from the antenna) requires Maxwell's equations,
not just the "usual" Kirkhoff rules.
 
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