Unless you need precision, the op-amp stage, and its feedback isn't needed. The resistor, in the emitter leg of the MJE340 will provide enough feedback, all by itself. Just note that the IN-9 (12mA) uses more current than the IN-13 (4.5mA). But with a minimum hfe of 30, the base current into the MJE340, should be no more than 400uA. If you make the emitter resistor 330 ohms, it will have a drop of close to 4V across it, when 12mA is flowing thru the tube. That'll be ~4.7V from the base of the MJE340 to gnd. It will also look like a ~10K load at that base pin. That's all assuming an hfe of 30. Typically, it will probably be twice that value, and the load will look closer to 20K.
On Friday, March 29, 2013 6:19:40 PM UTC-7, rkvs wrote: > > Hi, > > I used a driver similar to th one shown here: > > http://www.instructables.com/id/Nixie-Tube-Music-Visualizer/step6/Design-Display/ > > But, I think i was not able to get any voltage output out of lm358 opamp. > If i drive the base of mje340 directly using a pot, in-9 seems to work. > Any ideas? > -- 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/msg/neonixie-l/-/EkTPriL27L4J. For more options, visit https://groups.google.com/groups/opt_out.
