On Mon, 17 Mar 2014 07:44:03 -0700 (PDT), you wrote: >Actually, there's a Microchip app note, that describes the very same >technique. Personally, I don't like using it. I have a lot of respect for >Mike Harrison. He's a real sharp guy, and I'm really thankful for his >website ! As Nick mentioned, this is a really old design, and Mike just >probably whipped it up, quickly. He probably never imagined that nixie >tubes would become as big as a fad, as they are. He might have designed it >differently, had he known that more people, than just other geeky >engineering types, would be trying to build it. I got into the nixies, in >the summer of 2003, and the hobby (and this clock design) had already been >in existence a few years. Who knew, it would have this staying power !? > >On Monday, March 17, 2014 1:11:15 AM UTC-7, petehand wrote: >> >> On Sunday, March 16, 2014 10:41:54 PM UTC-7, threeneurons wrote: >>> >>> This circuit uses high value resistor, and *lets the 4013's static >>> protection, clamp the voltage*. >>> >> >> Surely you cannot be serious! >> >> Haha, threeneurons, you had me there. For a moment I actually believed >> someone might be ignorant enough to do it that way. >>
Yes, it can cause minor issues on microcontrollers with analogue circuitry due to current flowing in paths that can cause unwanted offsets, but for simple logic, provided that the source current is sensibly limited, it generally works just fine, though probably a good idea to use it on a schmitt trigger input to guarantee a clean switch. I only recall a couple of reports of erratic timing over the years. A large (few meg) resistor between S and Q might help by adding some hysteresis. Yes, it was designed pretty quickly, and there are other aspects of that 15-year-old design I certainly would do differently, like the dodgy, timing-sensitive hours reset logic, having the seconds dividers in the wrong order and the slow time-setting, but the mains supply and 50Hz input would be low on the list of changes. I like the lack of a lumpy mains supply, which allows for some very compact constructions. I might have published an alternate LVAC or DC+xtal option as alternatives if I'd realised how popular it would become. The original goal was something small, simple and not using a microcontroller, which at the time was relatively expensive, and needed a programmer, which many people wouldn't have had. My biggest regret is that I didn't buy a big stock of tubes *which were going for peanuts at the time) to do some kits, or sell PCBs. -- 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/pk2ei913d4bi5359qsoolh25pmuq1gjqkc%404ax.com. For more options, visit https://groups.google.com/d/optout.
