Yes, that was the only vague speculation I could come up with too - displaying a 3 bit 'byte' in early binary calculators or similar. But I've not found any documentation that points in that (or indeed any) direction. The obscurity of the application probably accounts for why they're as rare as hen's teeth now.
Jon. On Thursday, October 29, 2020 at 1:47:23 AM UTC gregebert wrote: > I'm going to guess it was an attempt to use octal-based math (which is a > subset of binary) in early computers, instead of decimal, because of the > greater efficiency in calculations. From what I've gathered, dekatrons were > an electronic mimic to the base-10 mechanical adding machines. But computer > science theory and electronics soon converged on binary, which we still use. > > Remember the PDP-8 ? It was 12 bits, or 4 octal words. > > On Wednesday, October 28, 2020 at 4:01:06 PM UTC-7 Jon wrote: > >> Misery? How can such a lovely tube be the cause of misery? :) >> >> So, the mystery tube is a Rodan DK25. Grahame correctly deduced from the >> picture that it is a three-guide (single pulse) base-8 selector dekatron. >> It's hooked up in a standard single pulse circuit which automatically >> creates fast transfers from G1 to G2 and from G3 to the 'next' main >> cathode, so what we're looking at is the persistence of vision effect of >> the glow resting predominantly on the G2 guides and main cathodes. 8 main >> cathodes, 8 sets of guides G1, G2, G3 for a total of 32 pins, of which half >> are visibly glowing in this regime. >> >> The DK25 is the only base-8 counting tube as far as I know, which is why >> the picture is truly diagnostic of the precise model of tube. Why Rodan >> made it, I have no idea, but it was a regular catalogue item not some >> weirdo developmental. There is a conventional base-10 selector tube in the >> same form factor, the DK24, which is much more commonly found, and even >> more oddly a base-6 tube too. That last one's a bit easier to understand >> from an application perspective, as base-6 and base-12 tubes (like the ETL >> GC12/4B & GS12D) are useful for counting time. >> >> So a real oddball, which I'm very pleased to have in the collection! >> >> Jon. >> >> On Friday, October 23, 2020 at 6:13:14 PM UTC+1 Pramanicin wrote: >> >>> Come on Jon, put us out of our misery..... :) >>> >>> On Sunday, October 18, 2020 at 9:27:51 AM UTC-7 Jon wrote: >>> >>>> >>>> Sharp eyes Grahame, and some sharp deductions too... >>>> >>>> The tube is indeed spinning, quite quickly. So we are looking at a >>>> persistence of vision effect, but not one created by a highly specific >>>> camera shutter speed - this is what the tube looks like to the naked eye. >>>> And neither is the tube being abused with a funky hook-up, it's operating >>>> in the manufacturer's reference circuit (might be give or take on the odd >>>> component value, I don't remember). It is a commercial tube, not a >>>> prototype / developmental tube. Your comment on mica vs ceramic is spot on >>>> - the family of tubes of which this is a member do switch from mica >>>> supports to ceramics. I have not actually seen an example of this >>>> particular type with a ceramic support, but I have no reason to believe >>>> they were not made. >>>> >>>> So, very nice progress. Anyone able to get us all the way over the line? >>>> >>>> Jon. >>>> >>> -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/a5879daa-1ddd-47d1-9eaa-1a7a94984cd1n%40googlegroups.com.
