Even though the nixies operate around 170V, they provide some voltage drop so that the driver doesn't see the full 170V. If you use a driver rated at a lower voltage, you want to provide protection as Mr. Forbes does (the zener diode) so that the driver doesn't get stressed from leakage current.
The other option is to use a driver rated for the anode supply voltage. If you do neither of the above, it's possible for leakage current thru the nixie to result in voltage higher than the driver is rated for. At this point, welcome to the jungle..... Whether or not a driver degrades over time is a matter of device physics. My own belief is that MOS devices will get destroyed because oxide destruction is voltage-related. Bipolar (ie NPN) destruction results from excess current (basically melting) so I think as long as the current is very small, on the order of micro-amps, the driver wont get destroyed. But I do wonder if there is long-term reliability impact (degradation) from some other mechanism that would cause leakage to increase over time. -- 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/7d67a2f9-f36e-45e6-86b8-9feee92fbc93%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
