> I have discovered the PT6311 which will handle all of my multiplexing and was > in heaven. After reading the datasheet, I discovered that it uses a negative > supply for the VFD. I made a voltage inverter and tried testing it out on a > tube to see what the connections are. This is where I do not understand it. I > had been giving the tube about +25V to the grid and Anodes with the HV5812 > but I am not sure what the connection is with the PT6311, if it even works > with a VFD tube for a -25 power supply. > > The heater has +5V supply with an appropriate resistor in both circumstances. > > I put -25V on the grid and Anodes, then tried just -25V to the Anodes and the > grid to ground and it doesn't light up. > > Does anyone have any suggestions?
The VFD only cares about the difference of voltage between its elements. So the grid and anode have to be more positive than the cathode to light it. The PT6311 is arranged so that the cathode is run at -25V, and to turn segments on, the grids and anodes are pulled "up" to ground, making them more positive than the cathode. To turn them off, it pulls then down to -25V. I have some commercial VFD inverters from surplus companies that produce -30V, along with a floating center-tapped 6VAC output to power the filament. I connect the -30V to the filament center tap. The tricky part is interfacing logic to the PT6311 - sometimes it's easiest to float the logic supply. - John -- 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 post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/32F1F42D-4C7E-4B0C-9BC1-060834BA8611%40mac.com. For more options, visit https://groups.google.com/groups/opt_out.
