On Oct 17, 8:14 am, "[email protected]" <[email protected]> wrote: > My experience is with B7971's multiplexed at a 2kHz rate. There was > no obvious flickeing. But there was a lot of acoustic noise and radio > frequency interference that was clearly produced by the > multiplexing. > > In another discussion, someone raised a concern about reduced > lifetime. I don't know about that, but I do know that the three > clocks I built about 35 years ago are still going strong, so that is > 18 tubes running over 200,000 hours.
A 2KHz there's not going to be any flickering, unless you're a hawk. Human eyeballs can't respond that fast. Is that 2KHz the 'commutating' rate, or the the total 'refresh' (frame) rate ? The frame (or refresh) rate is the commutating rate divided by the number of tubes (assuming 1 of n multiplexing). For most humans a refresh rate 60Hz, or more, will not flicker. That's a commutating rate of 240Hz, for 4 tubes, and 360Hz for 6 tubes. Again assuming only one of the 4 (or 6) tubes ON at any time. As for life, it only became a question if you're really upping the anode current, to compensate for brightness, well in excess of the maximum recommended 'steady state' current. If you keep the current in the specified range, there is not going to be a problem. Brightness will go down, but nixie clocks are usually in a much dimmer room (at home), than the bright rooms in a work environment. 'Singing' only seems to be a problem with the larger tubes (ie IN18 ...). Its probably due to the multiplexing rate being at the mechanical resonant frequency (or harmonic) of the tubes metal components. There might be some variation between digits, and the anode. You can adjust your commutating rate, and see if you can make it come and go. In short, multiplexing is not a problem, if you do your homework. Since you seem to be going the uC (Arduino) route, then you have a lot of control over you're particular commutating frequency. Therefore, you can play with it to control both flicker and singing. As for life, keep the current in spec (not too high AND not too low - that's bad too), and mux'ing ain't a problem. Its only a problem for the lazy. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
