Filaments are about 1.1V; you want to limit the current to 200mA max. 180mA is quite good and will prolong the filament lifetime. The anode is typically 1850V, at 30uA.
The anode current determines the brightness, which is the 'wear-and-tear' on the phosphor. So, keeping the anode current on the lower side so that the tube is still readable is essential. Lastly, the 10 individual grids control the numbers displayed. When a grid is negative with respect to the filament, say -3.5V or more negative, that character is extinguished. When the grid is positive with respect to the filament, that digit will be displayed. The brightness of the digit can be controlled by adjusting the anode voltage, or by adjusting how positive the grid is relative to the filament. In my NIMO clock, I have a DAC to set the offset voltage between the filaments and the grid logic. The grids are driven from CMOS shift registers on a 10V supply. The HV supply is also software-programmable. On Thursday, October 1, 2020 at 8:01:15 PM UTC-7 martin martin wrote: > Just curious, what's the filament voltage? 27VDC? And what's the HV? > > > > > ~ > *[email protected]* > > > On Thu, Oct 1, 2020 at 5:24 PM Paul Andrews <[email protected]> wrote: > >> Yes, they do look very nice. >> >> On Oct 1, 2020, at 4:44 PM, jörg <[email protected]> wrote: >> >> Short update of my nimo project. >> I've got 5 tubes running. The sixt is unfortunately DOA. >> The tubes filaments are driven with three power supplies, with soft start >> IC (load switch). >> So the filament gets started very smooth. >> I've made some experiments with multiplexing the tubes. >> Which work nice, using the method described in the manual. The bias >> voltage is changed for every tube, that should be on/off. >> In the actual approch, I'm using direct driving the tubes via 74HC595 >> shift registers. Got a plenty of problems at the beginning. >> The power and signal lines for the 595 were messed with switching noise. >> Some caps did the trick. >> Really nice to view the working tubes. >> >> Video: https://www.youtube.com/watch?v=JbwfZhYhnlo >> >> jörg schrieb am Mittwoch, 15. Juli 2020 um 18:01:18 UTC+2: >> >>> I‘m using Eagle to layout. >>> It takes time for me to feel comfortable with it. >>> And Fusion360. >>> >>> -- >> You received this message because you are subscribed to a topic in the >> Google Groups "neonixie-l" group. >> To unsubscribe from this topic, visit >> https://groups.google.com/d/topic/neonixie-l/nwics2gzVKE/unsubscribe. >> To unsubscribe from this group and all its topics, send an email to >> [email protected]. >> To view this discussion on the web, visit >> https://groups.google.com/d/msgid/neonixie-l/59a3f33b-d709-42e1-a631-d36c5858f19dn%40googlegroups.com >> >> <https://groups.google.com/d/msgid/neonixie-l/59a3f33b-d709-42e1-a631-d36c5858f19dn%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> <IMG_3999.jpg> >> <IMG_4008.jpg> >> <IMG_4003.jpg> >> <IMG_4009.jpg> >> <IMG_3999.jpg> >> >> -- >> > 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 [email protected]. >> To view this discussion on the web, visit >> https://groups.google.com/d/msgid/neonixie-l/7912DA8E-ED88-44D5-A040-B146B5292E2D%40gmail.com >> >> <https://groups.google.com/d/msgid/neonixie-l/7912DA8E-ED88-44D5-A040-B146B5292E2D%40gmail.com?utm_medium=email&utm_source=footer> >> . >> > -- 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 [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/f1273a15-4388-46b5-a63e-fd9f445df8fan%40googlegroups.com.
