Nixies: stupid questions.

CowJam:

wyager: Are you using an anode resistor? That's crucial. It sounds to me like something's up with your driver IC. Can you post a schematic?

No, what size resistor?

My circuit is as described - no resistors or caps or anything. The nixie plugs into the IC and 180v+, the arduino plugs into the four IC logic pins and the IC is also linked to +5v and GND. All the grounds are linked.

For what I know this should work. I have a couple of nixies here and I am starting to work with nixies those days. I will give a try to this setup (that should work, in my opinion) F

CowJam:

wyager:
Are you using an anode resistor? That’s crucial. It sounds to me like something’s up with your driver IC. Can you post a schematic?

No, what size resistor?

My circuit is as described - no resistors or caps or anything. The nixie plugs into the IC and 180v+, the arduino plugs into the four IC logic pins and the IC is also linked to +5v and GND. All the grounds are linked.

The resistor depends on the specs of the Nixie in question. For instance I have some sub-miniature Russian IN-17 nixie clones that are speced for 170V and 47k series resistor. The sheet I have says they will work at lower voltages and upto 82k series resistor. The series resistor goes on the anode to avoid having resistors for every cathode (which can directly connect to the driver).

That said I haven’t tried interfacing these tubes yet, I’ve merely verified they light up.

Thanks. They're number 12s. I got a dozen of them, sockets and the ICs from Ukraine (gotta love ebay!) - they look Russian (cyrilic writing on them).

I'll have a play tonight and see what else I can break ;)

I've got them working, thank you everyone (especially wyager).

I slapped a 33k ohm resistor on the anode and it's working fine now using a fresh IC (I've permanently damaged the first one).

Excellent! It was probably just too much current that damaged the old IC.

Yeah. I'll get the hang of this electrickery stuff eventually!

Spoke too soon! http://arduino.cc/forum/index.php/topic,50274.msg358237.html

No! That's awful! =(

I am following your experiment and as soon as I finish my pov experiment I will apply them to nixies... Where did you find the datasheet for yours? I have just tried to light up my IN-14 from my DCDC power supply but I am quite sure that the others little blulbs that I have, IN-3 (just neon bulbs) can't work at 170v...

I googled for it. Not sure I had a datasheet for my actual nixies, but I got the datasheet for the chips (which came with the nixies) by googling, and this is it: http://cowjam.co.uk/arct/k155id1.pdf

I've got some IN-35s which are just neon bulbs and they run fine at 180v (or whatever my circuit is running at) and ran fine with or without a 33k ohm resistor. These ones: http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=390206146006&ssPageName=STRK:MEWNX:IT#ht_864wt_905

We bought nixies from the same vendor :slight_smile:
Mine are those
http://cgi.ebay.it/ws/eBayISAPI.dll?ViewItem&item=400174245756&ssPageName=STRK:MEWNX:IT
I am going to try to drive them at 170v and see…
After reading about your experience I was thinking that multiplexing and optocouplers should be the safest way…

Yeah, optocouplers are the way to go!

If I figure out what happened I’ll report back on here.

BTW guys, small neon bulbs should have at least 100K resistors (some use 200K) at 170+V or else they could burn out themselves or your circuit. I am able to multiplex them at 170v with a 100K resistor. Remember that the gas inside them will change its resistance until the voltage across the lamp is the sustaining voltage. A 200K resistor (which is probably better for long life) makes them look a little sputtery.

My A1As regulate themselves at 60V, which means that 110V gets dropped over the anode resistor. 110V/100000?=1.1mA. Almost twice the recommended amount, but I figure since I'm multiplexing... Still probably not healthy.

wyager, thanks a lot for the advice. I am going to follow it!

Federico: wyager, thanks a lot for the advice. I am going to follow it!

This ^ !

No problem. Also, 666 posts cowjam. 8)

the number of the beast ]:D

By the way i see that you (wyager) use a lot of transistors for driving your project. Don't you have a 74141 off hand?

ps. the optocouples i need, TLP627, are damn expensive :fearful:

Federico: the number of the beast ]:D

By the way i see that you (wyager) use a lot of transistors for driving your project. Don't you have a 74141 off hand?

ps. the optocouples i need, TLP627, are damn expensive :fearful:

I was basing my project off parts I could get from digikey and I couldn't find any HV nixie drivers. The MPSA42s were only like 5 bucks for 25 IIRC, so I just went with those. I suppose after the shift registers and resistors and perfboard, the 74141s off ebay would have been cheaper, but it was a learning experience anyway. :P

BTW, are the optocouples to protect the rest of the circuit from high voltage?

I don't know if this will have contributed to the burnout, but I have discovered that I'd got the pins all muddled.

The power and ground pins were fine, but I had misinterpreted the position of the nixie pins so that I had the number sequence reversed.

I had also failed to spot the utterly confusing layout of the logic pins on the IC. If you look you'll see that the pins are labelled A, D, B, C (in that order). The logic chart is labelled D, C, B, A.

I will have undoubtedly sent things to the IC that it wasn't expecting, though the logic chart says that should merely have resulted in no output.

wyager: BTW, are the optocouples to protect the rest of the circuit from high voltage?

I need them for multiplexing the nixies. If I connect all the cathodes to the nixie driver IC then I need a way to switch on the 170v anodes. I am experimenting the tlc5940 but I can't let it manage the high voltage. That's way I tought about optocouplers connected to the high voltage anche my TLC to open and close the gate.

CowJam: I had also failed to spot the utterly confusing layout of the logic pins on the IC. If you look you'll see that the pins are labelled A, D, B, C (in that order). The logic chart is labelled D, C, B, A.

So the datasheed is wrong?? Anyway it looks like a strange way for burning an IC...