> Do I understand correctly, that they work just like a resistor? It *is* a resistor, one with a largish positive temperature coefficient.
> My plan is to drive IV-6 filament by directly PWMing it from 5V or 3,3V. It > normally requires 50mA@1V, so if the filament works just like a resistor, can > I PWM it with low duty cycle (4% on 5V and 9,2% on 3,3V)? Of course PWM > frequency will be something above 25kHz to avoid any noise. Will the wire > burn from short current spikes? > I don't like the idea of adding a dropper resistor. on 5V I will be losing 4x > the power needed to warm the cathodes! I prefer to drive them with AC. The idea is similar to PWM, but with two out of phase waveforms. I use a series capacitor to limit the current without wasting energy. A MAX628 or similar MOSFET driver makes a dandy driver, it has two channels, one inverting and one non-inverting, so a single PWM signal can provide both phases. It has plenty of current capability, so it can drive all the filaments in parallel (one series capacitor each to set/limit the current). A side advantage of this approach is that if you're driving it with (say) 5V, the average voltage is half that, so the filament is effectively at a small positive voltage. Then when you ground a grid to turn off a segment, it appears as a negative bias and turns it off solidly. - 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 neonixie-l+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/C3E013EC-FB71-4D12-B219-38290F4A3F6E%40mac.com. For more options, visit https://groups.google.com/d/optout.
