DC gas ionization lamp?

[David Masters]

I am looking for something like a common flourescent or neon tube, but
one that runs on pure DC.

I don't mean it runs off an inverter but uses HVDC direct to the tube
to maintain ionization of the gas.

An AC ignition voltage would be OK as long as the tube runs on DC once
ignited.

I believe some cinema projection lamps do this, but they are far to
powerful and expensive in terms of power supply and heat generated.

Color, wattage or gas content does not matter, but the tube must be
cylindrical with diameter within the 10-30mm range. Length is not
critical.

What would be the best off-the-shelf solution for doing this?

Much thanks,

David Masters

 

[BFoelsch]

I am looking for something like a common flourescent or neon tube, but
one that runs on pure DC.

I don't mean it runs off an inverter but uses HVDC direct to the tube
to maintain ionization of the gas.

An AC ignition voltage would be OK as long as the tube runs on DC once
ignited.

I believe some cinema projection lamps do this, but they are far to
powerful and expensive in terms of power supply and heat generated.

Color, wattage or gas content does not matter, but the tube must be
cylindrical with diameter within the 10-30mm range. Length is not
critical.

What would be the best off-the-shelf solution for doing this?

Much thanks,

David Masters

Fluorescent lamps will run on DC, but you of course need special
current-limiting and starting circuitry to replace the ballast used on AC
applications. It is not difficult if you use pre-heat type lamps;
instant-start lamps are more challenging.

Exactly what are you trying to do? How much light do you need? How much lamp
life?

 

[Phil Allison]

"David Masters"

I am looking for something like a common flourescent or neon tube, but
one that runs on pure DC.

** Fluoro tubes will operate off pure DC.

Obviously the ballast and starting set ups have to be redesigned to suit DC.

You can get small fluoro lamps (5 watt) only 10mm dia and about 150mm long
from a lighting shop.

IIRC they run at about 150 volts and 30 mA.

What DC supply have you got ?



........ Phil

 

[Phil Allison]

"BFoelsch"



** You got spyware operating in my PC ??




........... Phil ;-)

 

[CC]

I am looking for something like a common flourescent or neon tube, but
one that runs on pure DC.

I don't mean it runs off an inverter but uses HVDC direct to the tube
to maintain ionization of the gas.

An AC ignition voltage would be OK as long as the tube runs on DC once
ignited.

I believe some cinema projection lamps do this, but they are far to
powerful and expensive in terms of power supply and heat generated.

Color, wattage or gas content does not matter, but the tube must be
cylindrical with diameter within the 10-30mm range. Length is not
critical.

What would be the best off-the-shelf solution for doing this?

Much thanks,

David Masters

A HeNe laser tube?

A hollow cathode lamp for a spectrophotometer?

Some of the projection lamps are Xenon short-arc, but these are
definitely expensive, at least $3500 for a bare bones system from
Hammamatsu.

You can run Xenon flashtubes at very low DC currents continuously, just
to get a dim blue-white glow.

What color do you want? Do you want a clear tube or not?

What about just a CCFL? I don't know if these run on AC or DC,
actually, just that they have the word "cathode" in the name.


Good day!

 

[Adrian Tuddenham]

I am looking for something like a common flourescent or neon tube, but
one that runs on pure DC.

Flourescent tubes will run on DC. The filaments are usually designed so
that, on AC, they are heated by bombardment on one half-cycle when they
are anodes and then have better emission properties when they are
cathodes. If you run the tube in one direction only, you may have to
consider heating the cathode from a small transformer.

The other problem with DC is that the tube will darken at one end after
a few hour's use because the mercury ions all migrate to one end. You
may need some sort of polarity reversal arrangement which operates from
time to time.

In the days when DC mains was still common, they used a special switch
for flourescent tubes, which reversed the polarity to the light fitting
each time it was switched on.

 

[Phil Allison]

"Adrian Tuddenham"

In the days when DC mains was still common, they used a special switch
for flourescent tubes, which reversed the polarity to the light fitting
each time it was switched on.

** That is a lovely, obsure old fact.

Is this from personal knowledge ?



............ Phil

 

[Adrian Tuddenham]

"Adrian Tuddenham"


** That is a lovely, obsure old fact.

Is this from personal knowledge ?

From reading up old textbooks to gain fundamental background knowledge.

 

[Don Lancaster]

I am looking for something like a common flourescent or neon tube, but
one that runs on pure DC.

I don't mean it runs off an inverter but uses HVDC direct to the tube
to maintain ionization of the gas.

An AC ignition voltage would be OK as long as the tube runs on DC once
ignited.

I believe some cinema projection lamps do this, but they are far to
powerful and expensive in terms of power supply and heat generated.

Color, wattage or gas content does not matter, but the tube must be
cylindrical with diameter within the 10-30mm range. Length is not
critical.

What would be the best off-the-shelf solution for doing this?

Much thanks,

David Masters

JKL Industries sells these by the bushel basket.

Otherwise, you are describing a NE-2 neon lamp.

--
Many thanks,

Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
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