Sounds good! I believe that the delay is needed because of capacitance of the tube - takes a little bit of time to discharge the capacitor.
- Michael Sangster On Jan 21, 5:58 pm, will <[email protected]> wrote: > Yep, it was a combination of the multiplexing and a problem with the > anode transistors. It turns out, having a small delay after turning > off the anodes is important. I already had a few µs between turning > the anodes off and back on for my shift register write functions, but > I needed to add what I believe was an extra 100 clock cycles (12.5us) > or else the MPSA92s would stay partially on and allow just enough > voltage to pass to cause an "off" bulb to flicker during multiplexing > and for the MPSA42s to register positive on my DMM. Now it's 100% > contrast, no flickering at all. Very nice looking. > > On Jan 21, 1:35 pm, "M.J.Sangster" <[email protected]> > wrote: > > > You would read a lower voltage because of the PWM, I believe it is an > > average value you are seeing. A scope would show the proper value. Or > > you could just slow down the PWM to maybe 2 seconds on, then your > > meter would show the proper value. > > > - Michael Sangster > > > On Jan 21, 12:00 pm, will <[email protected]> wrote: > > > > Now, my only concern is that my DMM only measures around 110 volts > > > between the +voltage supply and the cathode transistors, even though > > > there is 170v between +voltage and ground. I'll have to do some more > > > testing, but it looks like for some reason the transistor collectors > > > are hovering at about 50v... Maybe they just "seem" this way because > > > of the PWM? -- 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.
