David and gregebert, Thanks for your replies, they were very helpful. It seems I have had a somewhat profound misunderstanding of the operation of transistors but I've spent the last few hours looking at the schematic David referenced as well as other articles and youtube videos and I'm beginning to understand a little better. I kept thinking that once the transistor was saturated it acted pretty much like a short circuit from collector to emitter. Thanks again for your input I appreciate it very much!
Shep On Tuesday, March 29, 2016 at 4:56:36 PM UTC-6, nixiebunny wrote: > > Sorry, I meant to say a PNP transistor with emitter tied to 180V rail. > > On 3/29/2016 3:23 PM, David Forbes wrote: > > Shep, > > > > There are two polarities of transistors, NPN and PNP. NPN requires the > base to > > always be 0.6V more positive than the emitter, and PNP requires the base > to be > > 0.6V more negative than the emitter. > > > > The anode must be controlled from the 180V point, not from the 0V point. > The > > most straight-forward way to do this is with an NPN transistor whose > emitter is > > connected to 180V. The base is controlled by a high voltage NPN > transistor > > through a resistive divider, to allow the on/off command to be sent > across the > > 180V 'space'. > > > > An example of a multiplexed anode drive circuit that works is shown in > my old > > Nixie clocks... page 17 has the schematic diagram. > > > > http://www.cathodecorner.com/nc620akitman.pdf > > > -- > David Forbes, Tucson, AZ > -- 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/bb9f8370-eb17-418c-89f2-8f33788273c6%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
