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FrozenGate by Avery

HeNe tube question

weeba2kv

weeba2kv

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Ok i got this lil tube but i need to know how many volts it needs and milli amps
my quess is about 1800 Volt 4-6 mA am i right ?

2cr7cev.jpg


If it lights up i'll post some nice pics Thanks already.
 





My guess would be that it's roughly right, I'd guess 4-5mA at 1500V, but my guess can be off a bit. Maybe if you've got some model number or any info where you got it we can try to find some specs. Or you could compare it to other tubes this size.
 
It was labeled with KT115051 the tube is 11 cm.

but i know they run @ 4-5 mA-1500 1800 volt
 


well it lid up but the CCFL module died after 10 seconds haha
 
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HeNe lasers can take some electrical abuse, that ccfl module apparently not :)
Try to get a proper power supply, they're rarely on marktplaats, so ebay would be the place to look.
 
Solonar said:
Did you have a ballast resistor?
Click to expand...
No , the tube drew about 6-7 mA and that was about the max current the module could give ( but as i now saw later today ) I hooked the module on 15 V and not 12 that probably blew it

Lets see this thread is for now as a experiment to hook up tubes in a different way
I'm going to buy a new CCFL module and try again ( they cost 8 dollars )
If the lil tube get's extreme hot... then a ballast will be needed
 
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He-Ne tubes MUST have a ballast resistor, also, usually He-Ne power supplies have inside two different multipliers ..... the main one, that can supply the working current at the working voltage (this change from tube to tube) for maintain the plasma, and a second ladder elevator section following the first one, that just produce 8000 to 12000 V at some microamperes for ignite the tube, and become not working when the tube is on.

Not the same thing as a backlighting PSU for laptops.



EDIT: something like this one :)
 
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CCFL inverters put out AC, it's a good thing the inverter died because AC will destroy a HeNe tube in a matter of minutes, you may well have already done some damage.

That looks like the Uniphase barcode scanner tube I have. Mine wants about 1300V-1500V at 3.5mA. As someone else said, you *must* use a ballast resistor, and a properly current regulated power supply. The anode (+) end is the plain one, the cathode is connected to the aluminum can. Getting this backwards will destroy the tube very quickly due to sputtering on the anode mirror.
 
Cyparagon said:
How? :undecided:
Click to expand...

Notice the electrodes are asymmetrical. The cathode is a HUGE aluminum can to dissipate the heat from ion bombardment. The anode is a tiny little metal mount for the mirror, right up at the mirror. Connect it backwards or drive it with AC and the anode becomes a cathode and that tiny little mount sputters metal onto the mirror. The gain in a HeNe laser is so low that a single speck of contamination on the inside of either mirror can completely kill lasing.

Read Sam's laser FAQ, I'm not making this stuff up. I personally ruined a HeNe tube when I was a kid and didn't know any better by wiring it up backwards. Note that some tubes are more durable than others. The low gain "other color" tubes are especially fragile.
 
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james is spot on. You can beat them to death with high voltage or high current, but they won't last long on AC or backwards DC.

EDIT: At least they won't last long as a laser. The electrical discharge will always remain quite pretty, though.
 
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Interesting. But isn't sputtering lessened when the material is hotter? (hot cathode vs cold cathode) Is it a function of voltage, current, temp, or all of the above? Or is it because the cathode is further away from the mirror?
 
Cyparagon said:
Interesting. But isn't sputtering lessened when the material is hotter? (hot cathode vs cold cathode) Is it a function of voltage, current, temp, or all of the above? Or is it because the cathode is further away from the mirror?
Click to expand...


Sputtering is lessened when the material is hot enough to facilitate thermionic emission, but that means glowing hot. All of the above. Voltage is dependent mostly on the gas fill but will vary some depending on how much current you force through the thing. Cathode heating depends on current per surface area, and mirror contamination depends on the amount of sputtered cathode material and where it's located. There is another factor I forgot to mention, the cathode can is coated with oxides that improve its ability to release electrons while the anode has no such coating. When this coating is depleted, sputtering increases greatly and the tube is rapidly approaching end of life. The more current you shove through it, the faster the coating is used up. For a long lived tube, you want the cathode to be as large as possible, located far enough from the mirror that sputtered material condenses elsewhere, and the drive current should be the minimum that allows for a stable discharge and acceptable power output.
 
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