I found a reference: http://www.r-type.org/articles/art-132.htm that explains the difference. So I am using double pulse rather than an integrated single pulse to get the delay. The data sheet implies I should be using -80v pulses to drive the rings. I guess I will up the drive voltage when my optocouplers arrive. I ordered 80v ones, perhaps I should have ordered the 300v ones. Oh well, another $8 shipping if I must. Some useful parts from DigiKey: MOC8050M-ND optocoupler 80v SFH619A-ND optocoupler 300v HM4682-ND Hammond 186C120 transformer to isolate my CRT clock that is live to line. It has dual primaries and I will see if I can use it backwards to get two 120v outputs isolated from line (which will only work for 120v power in Canada/USA) 497-2344-5-ND ULN2003A 7 segment driver for Vacuum Fluorescent displays, stepper motors, relays. Observe voltage ratings. There is an 8 transistor version as well. Peter
On Thursday, February 18, 2021 at 10:27:29 AM UTC-5 peter bunge wrote: > I tried another Dekatron but I'm not sure what it is, and it doesn't work. > The glow just flickers back and forth on adjacent elements. > This tube looks a bit like the GS10C/S but has no markings, has a metal > base, and the end is domed instead of flat. It fits the same socket and > appears to have guide rings. > My high voltage optocouplers don't arrive until this afternoon and I have > already tried +/- 25v which is 30v above the rating of the optocoupler I am > using. They have not blown, yet. > I am trying to understand the data sheet for the GS10C/S, looking at > recommended operating conditions: > What does double pulse drive-amplitude mean? > What does Integrated pulse drive amplitude mean? > I just finished re-reading Ronald Dekker's description of how it works and > his experiments. > Peter > > On Thu, Feb 18, 2021 at 3:09 AM Jon <[email protected]> wrote: > >> Good to hear - another successful neon spinny thing! >> >> Jon. >> >> On Wednesday, February 17, 2021 at 10:55:59 PM UTC [email protected] >> wrote: >> >>> I tried my new circuit with the optocouplers using 270k for R5 & R6 and >>> 1k for R3 & R4. >>> It works within the limits of +0v and about -22v. It is interesting that >>> the other circuit did not work for low + bias. It must be the slower >>> positive edge as someone mentioned. I will use about +30 and -30v, whatever >>> the rectified transformer gives. >>> This is my preliminary software. It only counts up at present from 0 to >>> 9 fast (10Hz) slowing down to 1Hz then repeating. The delay between the >>> steering pulses depends on the speed so at 1 Hz you can actually see every >>> pin lit. I thought it a waste to not see them. I have not fully tried this >>> software, only a Dekatron test version, so if there are errors please >>> forgive me. There is a BCD version that also works. I may add a "Spinner" >>> between 0 to 9 counts in place of the 2 second delay, 1 second forwards and >>> 1 second backwards. >>> // main loop >>> while (1) // loop endlessly >>> { >>> for(j=1;j<=10;j++) // sets the delays >>> { >>> for(i=0;i<=9;i++) // the BCD digit displayed (Nixies, >>> etc) >>> { >>> // generate clock and BCD >>> output_high(pin_C4); // high for 10 uS >>> delay_us(10); >>> output_low (pin_C4); // end pulse >>> portC = i; // output BCD >>> // Dekatron clocking >>> output_high(pin_A5); // steering ring 1 >>> delay_ms(j*50); >>> output_high(pin_A4); // steering ring 2 >>> delay_ms(j*50); >>> output_low (pin_A5); >>> delay_ms(j*50); >>> output_low (pin_A4); >>> // period of sequence >>> delay_ms(j*100); // set period >>> } //end for i loop >>> delay_ms(2000); // wait 2 seconds after each 0 to 9 count >>> } //end for j loop >>> } //end of endless while loop >>> } // end of main function >>> >>> On Wed, Feb 17, 2021 at 4:00 PM Jon <[email protected]> wrote: >>> >>>> No hard figures - it's dependent on a bunch of factors; principally >>>> manufacturing quality, how you use the tube, operating temperature and gas >>>> fill. If you keep the operating current within spec and preferably at the >>>> lower end, avoid the tube getting heated from its surroundings and above >>>> all else keep the glow moving around all of the electrodes, they will last >>>> a seriously long time. The electrical properties will change gradually - >>>> the maintaining voltage rises and the latitude around the voltages >>>> required >>>> for reliable stepping decreases. So you were absolutely right to point out >>>> the importance of taking note of these elements of the spec when designing >>>> - you can get away with a lot on a NIB tube, but progressively less with >>>> age. Of course if the application requires clear glass to see the lovely >>>> glow, then the tube may reach end of its useful life in that application >>>> as >>>> sputtering gradually obscures the view, and that may happen well before it >>>> ceases to step reliably. >>>> >>>> I'm not surprised by gregebert's description of his A101 - his >>>> application sounds like a great recipe for a long dekatron life. The slow >>>> speed ones are tough as anything and they love to work! Just for context, >>>> I >>>> believe that the large majority of dekatrons working in the stores of the >>>> WITCH today are from the original complement of tubes the machine was >>>> built >>>> with at the start of the 1950s. Can't formally prove it of course, but the >>>> date codes are consistent with that. Also, as we've noted before on other >>>> Russian glow tubes, the guaranteed life spans on the datasheets are >>>> ridiculously conservative if the tubes are treated well. The A101 >>>> datasheet >>>> gives a 1000 hour life - his A101 has done 70x that! I have a similar >>>> experience with my IN9 clock - the prototype unit is still going strong on >>>> its original tubes after 120K hours - datasheet life is 1K hours. >>>> >>>> Note that we're talking here about use-related life limitation - the >>>> death in storage of the high-speed dekatrons is a whole different topic. >>>> >>>> Jon. >>>> >>>> On Tuesday, February 16, 2021 at 8:49:07 PM UTC Dekatron42 wrote: >>>> >>>>> No, unfortunately not, no hard figures - maybe Jon has. I've only read >>>>> in some books about dekatron construction (neon tube construction in >>>>> general where dekatrons are shown as special variations) that they have >>>>> similar lifespans compared to small neon lamps but that the complex >>>>> design >>>>> complicates the failure modes/rate and also that keeping >>>>> currents/voltages >>>>> within the values specified in the datasheet will guarantee that they >>>>> work >>>>> as long as possible. >>>>> >>>>> It depends on when you say a dekatron fails, it can get a silvery >>>>> finish on the glass so you almost can't see the glow but it still works >>>>> and >>>>> it can fail a lot earlier than that due to internal flash-overs due to >>>>> sputtering onto the ceramic material which means a current can flow in >>>>> this >>>>> sputtered material as the distance is shorter there compared to other >>>>> paths >>>>> (I have a few dekatrons with that failure and of course a few with a >>>>> silvery look). >>>>> >>>>> I have to count my dekatrons one day to see if I have enough to build >>>>> a second Harwell WITCH..... ;) :) >>>>> >>>>> /Martin >>>>> >>>>> On Tuesday, 16 February 2021 at 17:16:07 UTC+1 gregebert wrote: >>>>> >>>>>> *Martin* - Do you know how long dekatrons last ? I have an A-101 >>>>>> running as a spinner in one of my clocks, and it's been going 60RPM >>>>>> 24/7 >>>>>> for almost 8 years with no signs of degradation. I use 30k dropping >>>>>> resistors at the cathodes, and the current is right at the spec value of >>>>>> 450uA, so that gives about 15V for "steering", and the driving waveform >>>>>> is >>>>>> 3-phase with overlap. I >>>>>> >>>>>> On Tuesday, February 16, 2021 at 4:15:05 AM UTC-8 Dekatron42 wrote: >>>>>> >>>>>>> There is one more dimension to think about when running a dekatron >>>>>>> and that is that over time it will degrade due to sputtering affecting >>>>>>> the >>>>>>> electrodes and to maintain a correct counting when it ages you should >>>>>>> keep >>>>>>> the voltages as described in the datasheet, especially the guide and >>>>>>> bias >>>>>>> voltages as those are needed when the dekatron nears its end of life - >>>>>>> it >>>>>>> is the same effect that is in play if you want to raise a dekatron from >>>>>>> the >>>>>>> dead if it has been heavily used or just stored for a very long time >>>>>>> without use, raise the bias/pulse voltages and sometimes the anode >>>>>>> voltage >>>>>>> to surpass the effects of the sputtering - effectively increasing the >>>>>>> current flow between the anode and the guides/cathodes. >>>>>>> >>>>>>> So even if dekatrons work at other voltages you will see the effects >>>>>>> of lower/incorrect voltages when they near their end of life, this has >>>>>>> been >>>>>>> described in older litterature where the internals of dekatrons has >>>>>>> been >>>>>>> disected in detail - you might just need some 10V below the glowing >>>>>>> cathode >>>>>>> to move the glow on a new dekatron but as it ages it will stop working >>>>>>> at >>>>>>> that voltage. >>>>>>> >>>>>>> /Martin >>>>>>> >>>>>>> On Tuesday, 16 February 2021 at 00:53:36 UTC+1 [email protected] >>>>>>> wrote: >>>>>>> >>>>>>>> Those values were left over from the 5v circuit. I was more >>>>>>>> concerned with the level shifting from the PIC at 0 to +5v. >>>>>>>> Peter >>>>>>>> >>>>>>>> On Mon, Feb 15, 2021 at 6:48 PM Jon <[email protected]> wrote: >>>>>>>> >>>>>>>>> I'd had a similar thought about increasing the bias resistors - >>>>>>>>> it's not necessary to run so much current (5mA) through that part of >>>>>>>>> the >>>>>>>>> circuit. >>>>>>>>> >>>>>>>>> OK, so your proposed conditions are that the dekatron will see are >>>>>>>>> 400V anode to main cathodes; guides swinging from +25V to -25V with >>>>>>>>> respect >>>>>>>>> to main cathodes. Tube current will be about 345uA. >>>>>>>>> I've replicated these on my dekatron tester using a nice NIB >>>>>>>>> GS10C/S as the test subject and can confirm that they do work - the >>>>>>>>> tube >>>>>>>>> stepped fine up at speeds up to over 4kpps once I'd woken it up a bit. >>>>>>>>> >>>>>>>>> Caveats: >>>>>>>>> 1) I only tried one tube. >>>>>>>>> 2) My circuit is rather different to yours so although the static >>>>>>>>> voltages are the same, the pulse shapes are almost certainly >>>>>>>>> different. And >>>>>>>>> we didn't even talk yet about pulse durations, so I've no idea what >>>>>>>>> your >>>>>>>>> PIC is spitting out. But as long as you're not trying to cut things >>>>>>>>> too >>>>>>>>> fine, there's lots of latitude to find patterns that work. Keep >>>>>>>>> things >>>>>>>>> north of 100us per phase and you'll be fine unless you've got a >>>>>>>>> really >>>>>>>>> reluctant tube. >>>>>>>>> 3) I was running at slightly lower current (300uA) so you've >>>>>>>>> probably got a bit more margin for speed than I had. Recommended >>>>>>>>> operating >>>>>>>>> conditions are 325uA +/- 20%, so we're both inside that range. But a >>>>>>>>> little >>>>>>>>> more rather than less current is useful when pushing higher speeds. >>>>>>>>> I'm >>>>>>>>> guessing though that you're looking for a much slower stepping speed >>>>>>>>> for >>>>>>>>> this application though. >>>>>>>>> >>>>>>>>> If you've not already done so, I'd definitely second Martin's >>>>>>>>> recommendation to take a look at Michael Moorrees' dekatron work (he >>>>>>>>> looks >>>>>>>>> in here from time to time too). He used a couple of elegant design >>>>>>>>> tricks >>>>>>>>> which simplify the interfacing of dekatrons to modern electronics / >>>>>>>>> microcontrollers - I've followed his approach in pretty much all the >>>>>>>>> stuff >>>>>>>>> I've built and it works a treat. Not to say that other approaches >>>>>>>>> aren't >>>>>>>>> equally useful too of course. >>>>>>>>> >>>>>>>>> Jon. >>>>>>>>> >>>>>>>>> On Monday, February 15, 2021 at 9:39:13 AM UTC Dekatron42 wrote: >>>>>>>>> >>>>>>>>>> I'd raise the resistance to at least some 100k for the two bias >>>>>>>>>> resistors R5 & R6 in your diagram above. >>>>>>>>>> >>>>>>>>>> I'd also use the correct bias voltage and just use an MPSA42 with >>>>>>>>>> its emitter to common ground for the driver to simplify the circuit >>>>>>>>>> as >>>>>>>>>> Ronald Dekker and Michael Moorrees with their dekatron circuits. >>>>>>>>>> >>>>>>>>>> Different dekatrons need different bias and pulse voltages on the >>>>>>>>>> guide electrodes to count properly so accomodating for those >>>>>>>>>> requiremenst >>>>>>>>>> will remove a lot of problems and keep down the fault finding time. >>>>>>>>>> >>>>>>>>>> /Martin >>>>>>>>>> On Monday, 15 February 2021 at 03:05:12 UTC+1 [email protected] >>>>>>>>>> wrote: >>>>>>>>>> >>>>>>>>>>> You are absolutely right. 5v was not high enough despite >>>>>>>>>>> Ronald's and my confirmation that it would work. >>>>>>>>>>> I am changing to +25v and -25v and will have an optocoupler with >>>>>>>>>>> the diode driven from the 5v PIC and the transistor at the bottom >>>>>>>>>>> of the >>>>>>>>>>> resistor between the two power supplies. It keeps it simple. I have >>>>>>>>>>> to >>>>>>>>>>> order the optocoupler because none of my old ones have higher than >>>>>>>>>>> 30 v >>>>>>>>>>> rating. >>>>>>>>>>> I will have to think about the extra two power supplies. Maybe I >>>>>>>>>>> can't avoid them. It will be a few days until I get the parts. >>>>>>>>>>> Peter >>>>>>>>>>> [image: Dekatron Circuit.jpg] >>>>>>>>>>> >>>>>>>>>>> On Sun, Feb 14, 2021 at 3:18 PM Jon <[email protected]> >>>>>>>>>>> wrote: >>>>>>>>>>> >>>>>>>>>>>> Interesting approach - not seen it rigged up quite like that. >>>>>>>>>>>> Let us know how it goes! >>>>>>>>>>>> >>>>>>>>>>>> My immediate question is whether there's a big enough potential >>>>>>>>>>>> difference between an inactive guide and a main cathode to get a >>>>>>>>>>>> reliable >>>>>>>>>>>> transfer forward from a deactivating G2 to the 'next' main cathode >>>>>>>>>>>> rather >>>>>>>>>>>> than back to the adjacent recently used G1 - 5V is much lower than >>>>>>>>>>>> the >>>>>>>>>>>> datasheet guide bias. Might be OK at slow stepping speeds with >>>>>>>>>>>> long guide >>>>>>>>>>>> pulses. Also the leading edge of your guide pulses is going to be >>>>>>>>>>>> fairly >>>>>>>>>>>> slow as Q1/2 come out of saturation and the guides are passively >>>>>>>>>>>> pulled >>>>>>>>>>>> down to the 'active' voltage. Most guide drive circuits use a NPN >>>>>>>>>>>> pull-down >>>>>>>>>>>> to the active state which creates a sharp leading edge and then a >>>>>>>>>>>> slower >>>>>>>>>>>> return to the inactive state. >>>>>>>>>>>> >>>>>>>>>>>> Jon. >>>>>>>>>>>> >>>>>>>>>>>> On Sunday, February 14, 2021 at 7:06:28 PM UTC >>>>>>>>>>>> [email protected] wrote: >>>>>>>>>>>> >>>>>>>>>>>>> Having finished the Amperex 8453 display I started on my >>>>>>>>>>>>> Dekatron. Thanks to all for the suggestions. >>>>>>>>>>>>> I read up on Ronald Dekker's clock project >>>>>>>>>>>>> https://www.dos4ever.com/decatron/decatronweb.html >>>>>>>>>>>>> and decided against a direct drive from a 74141 because, even >>>>>>>>>>>>> if it was practical, it would not look as good as using all the >>>>>>>>>>>>> pins. It >>>>>>>>>>>>> would look like the 8453 I just finished except without the >>>>>>>>>>>>> number mask. >>>>>>>>>>>>> A few quick experiments showed that a -24v power supply was >>>>>>>>>>>>> needed for the easiest implementation.. This is my design. I will >>>>>>>>>>>>> let you >>>>>>>>>>>>> know if it works. >>>>>>>>>>>>> >>>>>>>>>>>>> A PIC drives the circuit: it starts with Q3 off to force a >>>>>>>>>>>>> start at 1. A high on R3 or R4 is the same as the switches in >>>>>>>>>>>>> Ron's test >>>>>>>>>>>>> circuit placing -24v on the guides. As my PIC sends the BCD for >>>>>>>>>>>>> the other >>>>>>>>>>>>> displays and clocks the E1T it will generate the sequence to >>>>>>>>>>>>> advance or >>>>>>>>>>>>> retard this Dekatron.. >>>>>>>>>>>>> [image: Dekatron Circuit.jpg] >>>>>>>>>>>>> >>>>>>>>>>>> -- >>>>>>>>>>>> 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 [email protected]. >>>>>>>>>>>> To view this discussion on the web, visit >>>>>>>>>>>> https://groups.google.com/d/msgid/neonixie-l/62979e37-ef21-46e1-9b7c-45a4c4080238n%40googlegroups.com >>>>>>>>>>>> >>>>>>>>>>>> <https://groups.google.com/d/msgid/neonixie-l/62979e37-ef21-46e1-9b7c-45a4c4080238n%40googlegroups.com?utm_medium=email&utm_source=footer> >>>>>>>>>>>> . >>>>>>>>>>>> >>>>>>>>>>> -- >>>>>>>>> >>>>>>>> You received this message because you are subscribed to a topic in >>>>>>>>> the Google Groups "neonixie-l" group. >>>>>>>>> To unsubscribe from this topic, visit >>>>>>>>> https://groups.google.com/d/topic/neonixie-l/dQn3tFBYfoc/unsubscribe >>>>>>>>> . >>>>>>>>> To unsubscribe from this group and all its topics, send an email >>>>>>>>> to [email protected]. >>>>>>>>> To view this discussion on the web, visit >>>>>>>>> https://groups.google.com/d/msgid/neonixie-l/75f258db-83ea-4df3-9d50-52dcaed1461en%40googlegroups.com >>>>>>>>> >>>>>>>>> <https://groups.google.com/d/msgid/neonixie-l/75f258db-83ea-4df3-9d50-52dcaed1461en%40googlegroups.com?utm_medium=email&utm_source=footer> >>>>>>>>> . >>>>>>>>> >>>>>>>> -- >>>> 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 [email protected]. >>>> >>> To view this discussion on the web, visit >>>> https://groups.google.com/d/msgid/neonixie-l/bcaa0282-1c44-4b37-9f6f-98845208efecn%40googlegroups.com >>>> >>>> <https://groups.google.com/d/msgid/neonixie-l/bcaa0282-1c44-4b37-9f6f-98845208efecn%40googlegroups.com?utm_medium=email&utm_source=footer> >>>> . >>>> >>> -- >> 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 [email protected]. >> > To view this discussion on the web, visit >> https://groups.google.com/d/msgid/neonixie-l/3cc6ab77-f4c7-4ae9-8d65-6a60653b7895n%40googlegroups.com >> >> <https://groups.google.com/d/msgid/neonixie-l/3cc6ab77-f4c7-4ae9-8d65-6a60653b7895n%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. 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