On Dec 19, 7:37 pm, John Rehwinkel <[email protected]> wrote: > > Power each tube's filament in parallel from the 5v supply, in series with a > > voltage dropping resistor. > It also has the advantage to soft-starting the filaments - cold filaments > have low resistance and draw heavier current until > they warm up. The series resistors limit this current surge. > > - John
This is how I do it for the IV-17 explorer kits I sell. I have tubes which have run for a couple of years now without any problem. in the muxh there is no visible signs of any gradient and even when the tubes are not muxed it is still true. the filament begins in the lower left of the tube, rises, folds over at the top of the tube and comes down to the pins again on the right side. Any gradient should be seen as a different in brightness of the left and right sides at the tube's base. I suspect that because of the close proximity of segments at the base to both sides of the heater (the higher voltage end on the right and the lower voltage end on the left) some sort of smoothing also takes place to even out the difference. Shorting out a resistor (in my case 1/2W 1210 SMD parts) would case the tube filament to receive too much voltage. I think I will add a note in my instructions so that builders protect those components well, if not with a case then a protective coating of some sort. Perhaps in the next revision i'll think about putting those resistors on the underside to really protect them well Chris http://groups.yahoo.com/group/smartsockets/ -- 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.
