You can use a lot of trigger tubes for dekatron coupling, the problem being to bias the trigger electrode correctly - a thing that is much more easy with the GTE175M. There are old East German magazines showing how to use the Z70U and the Z5823 and similar types. The problem is that they don't fit as easily as a coupling stage like the GTE175M does. They don't fit directly for all types of dekatrons as the output voltage change available across the cathode resistor on the dekatron might be too small to fit the trigger voltage necessary for the trigger tube to get a stable triggering point meaning that you will have to use a potentiometer to trim the bias point for each coupling stage. You will usually have to put a negative voltage on the cathode resistor on the dekatron instead of grounding it to get a high enough voltage to reach the necessary trigger voltage change. The Z70U was used as a coupling stage between ZM1070 dekatrons and the Z5823 was used together with Z562S. Since the ZM1070 and Z562S use almost the same voltages as any other dekatron it should be possible to adjust the circuits for them to work properly with any other dekatron as long as the output voltage across the cathode resistor is enough to reach a stable triggering point with the biasing technique. I've heard that Mullard had a coupling stage with the Z70U for their Z504S (identical to the ZM1070) but I have not seen any circuit diagram for it. There is also the possibility of using for instance the EF80 valve as a coupling stage like ETL (Ericsson) did for their GSA10G - have a look at circuit LK201 on page CT-12 here: http://tubehobby.com/datasheets/DEKA.pdf. The EF80 is cheaper than the 12AT7 and it also handles the cut-off for long times better than the 12AT7, the double triode 5963 would be a better choice for long cut-off periods as it was developed for just that purpose in computers. /Martin
On Thursday, January 31, 2013 4:00:50 AM UTC+1, threeneurons wrote: > Unfortunately, the only trigger that has the proper signal levels > to commutate a dekatron properly is the Ericsson GTE175M: > > http://frank.pocnet.net/sheets/022/g/GTE175M.pdf > > A dekatron's guides need to see an incoming signal of a very minimum of > 60V transition, negative. Its outputs a signal that only goes ~20V, and in > the wrong direction. Most triggers need a larger incoming signal. The > GTE175M can do the job. All the other ones I've seen can't. In the old > days, the interconnecting stage, between dekatrons was usually a vacuum > tube triode. The favorite was a 12AT7. Look at figure 4, in this document: > > http://frank.pocnet.net/sheets/084/7/7155.pdf > > > On Wednesday, January 30, 2013 1:19:28 PM UTC-8, Smiffy wrote: >> >> >> >> But this thread is rather timely - just yesterday I went back to trying >> to figure out how to cascade A101 Dekatrons to form a clock/calendar. >> Whilst I'd figured a simple way to do it, using a tiny microcontroller >> between each stage (which also makes it easy to set,) barring the initial >> timing source, I wanted to stay away from silicon if possible. Would >> something like an XC18 (now that I've located a source,) be suited to this >> task? (Sufficiently illuminated, that is.) >> > -- 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 post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msg/neonixie-l/-/wPiZz2MfaqwJ. For more options, visit https://groups.google.com/groups/opt_out.
