HeNe questions

Hello! So I'm one of the lucky ones who got one of those tiny little 6 HeNe tubes and matching PSUs that Ultimatekaiser was selling a while back.

I just got the ballast resistor in the mail today, and I wired it all up the way UK showed me, and the tube lights up and I get a tiny red dot out the end, but I'm getting a fizzing noise from the tube, and I can see the plasma in the tube flickering a bit. I only ran it a few seconds in case something might damage the tube.

I *think* its the the connections I've made to the tube. I don't have proper clips so i just wrapped the wires from the PSU around where the clips would go. Could that be the problem?

The only other thing I think it could be is that there isn't enough power going into the PSU. It says it needs 7-9 volts (no mA input rating), I'm just running it off a 9-volt battery. Would a 9-volt battery not provide enough current perhaps?

Also, one last thing, I've heard how HeNe tubes hold an electrical charge, so now I've basically got a quarantine on my desk where the tube is because I'm scared to touch it now.

Can any part of the tube shock me? Like the glass tube part? Or only the metal parts?

How can I safely discharge it? I've got 2 75K ohm 5 Watt resistors, if I put them in series and shorted the cathode and anode of the tube with them would that work?

Thanks!

It's not getting enough power, 9V cells are for smoke/CO2 alarms, that's about it. Make sure the anode resistor is as close to the anode as you can get it too.

Typically you'd need 9V at around 1-5 amps for a small-med HeNe. A 9V cell is only good for maybe 100mA for a short period of time.

Only the metal parts of the tube can shock you, and it's not lethal, just a real eye opener. Yes you can use those resistors to discharge it but you can't leave them in place when the tube is powered. I usually just use a 20" alligator clip lead to short out the ends, you won't harm it (save from scratching a mirror if you're wildly not careful).

Sigurthr said:

It's not getting enough power, 9V cells are for smoke/CO2 alarms, that's about it. Make sure the anode resistor is as close to the anode as you can get it too.

Typically you'd need 9V at around 1-5 amps for a small-med HeNe. A 9V cell is only good for maybe 100mA for a short period of time.

Only the metal parts of the tube can shock you, and it's not lethal, just a real eye opener. Yes you can use those resistors to discharge it but you can't leave them in place when the tube is powered. I usually just use a 20" alligator clip lead to short out the ends, you won't harm it (save from scratching a mirror if you're wildly not careful).

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Hey don't bash the (v, I have a teensy Hene that runs off one

"eye opener" for sure. Be extra careful, because I have always been careful, but always end up shocking myself -_-
Your connections aren't a problem, you can basically just set the wires on the tube ends (at that high of a voltage, you don't need a uber secure soldered connection for it to work). Clips certainly are nice though, because it prevents the wires from falling off (I just wrap the wire around the tube ends), because you don't want to run the supply without a load.

Ah. Wasn't aware 9 volt batteries were low current. Crud.

Only 9 volt power supply I could find was a 300 mA one. Darn.

Would 6 D batteries be able to put out enough current? Just so I can actually use the tube while I search for a 9 volt supply.

Yep, D cells work fine!

Found a better solution. Just taped 2 18650's in series. Plenty of current. Tube lit up nice and bright with no fizzing or flickering.

Loving glow of the plasma. Very neat, and not something a lot of people get to see or appreciate.

Also these little tubes are impressive. The dot is far brighter than my larger Novette HeNe.

EDIT: Is it normal for a bit of ozone to form from operating a HeNe tube? Getting a bit of it off mine.

You must be getting a bit of intermittent arcing on the connections then. Shouldn't be any ozone or corona.

Yeah sounds like a lack of current and bad connection. Glad you got it running more stable now, but I really do emphasize the use of clips I have some I can send to you in a envelope. A single 9 V battery will run them, but not for an extended amount of time. If you have the one of the little supplies that I was offering, it's a 3.7mA supply. They're rated for up to 4mA but 0.3 mA is not enough of a change to change the output on one this small.

As for discharging the tube yeah just use the other resistor to discharge it by bridging the ends, or let it sit for about 10. Min. That little one has bleed down iirc.

ultimatekaiser said:

. They're rated for up to 4mA but .3 mA not enough if a change to change the output on one this small.

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Didn't follow that. Nice to hear others are putting theirs to good use.

But Curious about running this off DC batteries instead of wall brick.

Since this was the start info on this thread. ----What batteries would you suggest for most efficient use for powering the little HeNe brick?

2x 18650
5x Alkaline D cells
6x NiMH D cells
3x CR2 3V Lithium

The Lightning Stalker said:

2x 18650
5x Alkaline D cells
6x NiMH D cells
3x CR2 3V Lithium

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Thats a whole lot of D cells

2x 18650 sounds ideal and like a plan.

Thanks

Any idea on run time (roughly) with the Group buy HeNe and driver?

icecruncher said:

Thats a whole lot of D cells

2x 18650 sounds ideal and like a plan.

Thanks

Any idea on run time (roughly) with the Group buy HeNe and driver?

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$ grep 'battery life calculator' ⏎

Okay dug through the group buy thread and found out how many watts they use (I had asked) and the answer is they use roughly 5 watts.

Sooo maths!

The 18650's I have are the nice 3400 mAh panasonic ones.

so 3.4 Ah X 3.7 volts os 12.58 watts. Ill just go with 12.5 watts for ease.

12.5 Watts per battery, using 2 of them is 25 watts. So you could run the HeNe tube for roughly 5 hours off of 2 high capacity 18650's.

Yeah they generally tun about 5-6 watts depending on your choice of ballast. With a 75K ballast it runs at about 1400VDC roughly at about 3.7-4mA so I get about 5-5.6 watts if my math is correct give or take a little. So yeah, about 4.5-5 hours on a good day in theory. Though the tube would likely drop out or become unstable before that... Which is really bad for the supply and tube. Maybe you should give it a try and let us know.

HeNe tubes have a limited run time? Do they get to warm or does the gas pressure increase to a point where it doesn't lase anymore?

ultimatekaiser said:

Though the tube would likely drop out or become unstable before that...

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I have never heard of that before. I
thought a good tube could run for days on
end. I have never run my HeNe that long
though.