58kohm resistors represent nixie tube digits. 10kohm resistor is anode resistor.
All digital inputs are active low.
Inputs through inverters select which tube is active. Inputs at the bottom (at drain of FETs) select which digit is active on the tube. (Only 2 tubes with 4 digits each are shown.)
A big drawback of this circuit is that a FET driver is required for each digit on each tube (for a clock, this would be 6x10=60 FETs!) - see my improved version called "Multiplexed Nixie Tube Driver for Clock - Optimized for FET count."
Logic inputs can be driven with BCD-to-DEC decoder similar to SN74LS145N to reduce required pins on microcontroller.
