IV-12 power supply for filaments (considerations)

More
4 months 17 hours ago - 4 months 1 hour ago #13047 by 64bittz
I'd say that if you haven't already, you should read this:
www.noritake-elec.com/technology/general...mation/vfd-operation
It's literally the only big source of information about VFD operation. It doesn't really say much about single digit tubes tho and it focuses on those long displays which need AC filament drive for sure. It is really an informative read on the topic in any way.

It's sad that there isn't at least some sort of book about theory and operation of VFD tubes.

The other real shame is the sheer lack of information about these russian vfd tubes. There might be some documents, but those need extensive translation work. I might get away with simple datasheets, but not whole component books.

EDIT: As I keep looking through the internet for information about VFDs. I keep finding more and more application guides.
This one is from Allegro Microsystems. They provide a bit more info, but still don't clarify much. Also the page where they put the zener to have a higher bias voltage on the cathode doesn't make sense since the other side of the filament is still connected to GND. Still it might be useful to someone coming across this forum

EDIT 2:
I found this (credit to www.vwlowen.co.uk)
Now this is more like it. It's actually a pretty good guide on VFDs. As always, it tends to focus on AC filaments for long displays. Still a great read on the subject

EDIT 3:
This handbook doesn't contain much information about VFDs (I can see that either noritake or them copied from each other) but at page 1116 (shown by adobe, not the actual page on the book) it says that for static drive of the segments -0.6v is enough to turn them fully off, with up to -12v in multiplexed mode (although it's again only talking about big displays, for single digit ones it should be fine)
Last edit: 4 months 1 hour ago by 64bittz. Reason: Edit 3
The following user(s) said Thank You: BS_Jim

Please Log in or Create an account to join the conversation.

More
4 months 17 hours ago - 4 months 16 hours ago #13048 by 64bittz
So I found this:
www.tubebooks.org/Russian.htm
the first file listed is a 300 page long handbook about indicators and displays. The problem is, of course, that it's entirely in Russian. It would need extensive translation just to understand what they are talking about.
I think I'm going to translate the chapter section to see if there's something interesting, I'll edit this post with any new info. Keep asking on that please

EDIT: after lookig through the databook I found some western equivalents for which information, believe it or not, is even harder to find. Seems like a dead end this way. Russians produced tons and tons of different indicators, even HP bubble leds clones. Needless to say, for 95% of those information is virtually impossible to find.
What I really need to find out is the Anode Cut Off voltage that is mentioned in the noritake guide. To make matters worse, they say it varies greatly depending on the technology of the tube. This is getting more and more frustrating
Last edit: 4 months 16 hours ago by 64bittz.

Please Log in or Create an account to join the conversation.

More
4 months 1 hour ago - 4 months 1 hour ago #13049 by 64bittz
I found the PERFECT piece of information

You can find where I extracted this in the second link in my next posts (the
Futaba Vacuum Fluorescent Display Application Note
www.vwlowen.co.uk)
This explains what that "conductive layer" is. It appears I translated correctly. Still doesn't say the polarity though, still needs some interpretation. My guess is that GND (or the lower end of the filament) has to be connected there seen the purpose of the layer. Any thoughts?
Attachments:
Last edit: 4 months 1 hour ago by 64bittz.
The following user(s) said Thank You: Ty_Eeberfest

Please Log in or Create an account to join the conversation.

More
4 months 1 hour ago #13050 by 64bittz
hi Jim, I updated the reply to this message with further information you might find useful. Have a look at it if you like

Please Log in or Create an account to join the conversation.

Moderators: AccutronTy_EeberfestIan
Time to create page: 0.094 seconds
Go to top
JSN Boot template designed by JoomlaShine.com