Hi Ron, Multiplexing was also often seen with LED displays (7 segment) and that worked very well because the segments are diodes. No currents that flow in unexpected ways.
Nixieclocks of the last decade also often use multiplexing. The ‘segments’ don’t behave like diodes at all. Many unexpected current paths exist, depending on which anodes are on, which cathodes are off. Be aware that identical digits of different tubes are connected in series, because the cathodes of these identical digits are all wired together. Disconnecting a cathode junction sets all these cathodes floating. There is always 1 active anode. From that active anode it is not difficult to find two digits in series, which leads you to another (turned off) anode, but that tube has at least one digit connected to ground. That is not a very good climate to ensure digits will turn off rapidly. This is the situation if single transistors are used as switching element. A 74141 has clamping zeners, and solves this problem by preventing the cathodes going too high. You could also lower the HV. Below 135 volt you will have no ghosting. If you add the voltage divider + diode, the cathodes (of your little neons) are not allowed to go higher than half HV. They are still in series between anode drivers, but not enough voltage left over to get ghosting issues. Frank From: Ron Schuster Sent: Saturday, September 08, 2012 4:13 AM To: neonixie-l@googlegroups.com Subject: Re: [neonixie-l] NE-2 lamps not fully blanking I've seen an arrangement something like that in some schematics I've seen on the web. Can you explain what that does? On Friday, September 7, 2012 10:58:57 AM UTC-4, Frank Bemelman wrote: Hi Ron, You could try two resistors of 47K in series, between HV and GND. Connect a diode 1N4148 or something, cathode to this voltage divider. Connect the anode to the collector of Q9. Your nixies are fine, because the 74141 has internal clamping zener diodes. Frank -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msg/neonixie-l/-/VQHzrwTr-qAJ. For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
