I agree with Greg, the voltage WRT Gnd is important for brightness (as its what gives the electrons the incentive to move in the first place). Series connected filaments on individual tube VFDs will give you a nice demonstration of the same aformentioned problems with linearity of brightness as DC driven filaments for long VFD displays.
By far the most used commercial approach I see (e.g. Nortake / Futaba VFD panels that run on 5vdc) is to have a small PCB mounted coupled inductor (fancy name for a smal high frequency transformer really) driven by a half or full H-Bridge arrangement. Secondary winding driving the filament with a center tap to main Ground. Other lazy way applcable here is to just use a small 50hz mains transformer as a PSU, with a center tapped secondary, center tied to ground - like virtually every VFD bedside alarm clock ever made... I doubt it would affect it if you also rectified each end of the winding with a diode and used it for your electronics (I think the last VFD alarm clock I killed for parts only had one center tapped winding on its transformer. They also tap off one side pre-rectification and square it up for timekeeping... As an aside, those DG12B tubes are beautiful! -- 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 view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/cc50e3ba-9b98-4bd5-a8e8-73a7eba27b22%40googlegroups.com.
