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.
