For multiplexed nixie tube designs, the idea of biasing is to keep the voltage of the anodes for tubes that are off below the sustaining voltage. Most nixies will ionize around 170V, and sustain around 135V. So if you bias them at 85V (half the supply voltage if you run at 170V), then you are assured it will be off.
In the context of the wikipedia article you mentioned, the bias they refer to is the static current thru a vacuum tube, and like nixie tubes, they will degrade faster at higher currents. I doubt biasing a multiplexed nixie tube to keep it off will affect it's life. Crossover distortion is irrelevant for nixie tubes because they are not used as amplifiers. One reason I dont use multiplexed drivers in my designs is because the tubes are not on continuously, so I believe that a multiplexed nixie would be dimmer than a direct-drive nixie running at the same current. If additional current is driven into the tube to make it brighter (to compensate for the loss of brightness due to multiplexing), I would be concerned about reduced lifetime. I dont believe tube lifetime is a linear function of current; doubling the recommended operating current would probably cut the lifetime much more than 50%. Multiplexing uses fewer transistors (which saves on component cost and PCB area), but that doesn't bother me because I can get transistors and PC boards very cheap; billions are made every year. Not true for nixies; I think Burroughs stopped making them about 40 years ago (I apologize for being such a zealot about brand-loyalty....) so the supply of nixies is finite and dwindling. Another reason I dont multiplex them is the datasheet advised against using long-life tubes in pulsed-mode, which implies not to multiplex them. Other tubes might be OK with multiplexing. -- 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/msgid/neonixie-l/62d71531-1055-40d9-a9c6-16769def153e%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
