Custom Nixies Perform When Cranked Up To 100,000 Hertz

With the popularity of Nixie clocks, we’d be forgiven for thinking that the glowing tubes are only good for applications with a stately pace of change. But we forget that before they became the must-have hobbyist accessory, Nixies were used in all kinds of scientific instruments, from frequency counters to precision multimeters. In such applications, update rates in the hundreds or thousands of Hertz aren’t uncommon, and the humble Nixie handled display refreshes with ease.

But what about refreshing a Nixie at 100 kHz? That was the question put to artisanal Nixie maker [Dalibor Farný] by a client who wanted a timer to calibrate high-speed cameras. It was a feat that [Dalibor] wasn’t sure his custom-made tubes could handle. The video below shows his efforts to find out.

If you ever wanted to know about the physics of gas-discharge displays like the Nixie, the fifteen minutes starting at about 5:13 will give you everything you need. That basic problem boils down to the half-life of excited neon, or how long it takes for half the population of excited molecules to return to the ground state. That, in turn, dictates how long a given cathode will continue to visibly glow after it’s turned off, which determines how many digits will appear illuminated at once.

To answer that, they engaged a company in Prague with a camera capable of a mind-blowing 900,000 frames per second. Even though they found a significant afterglow period for each cathode, even at 100 kHz it’s clear which digit is the one that’s currently illuminated. They also looked at the startup of digits in a cold Nixie versus one that’s warmed up, leading to some fascinating footage at around 26:30.

We appreciate [Dalibor]’s attention to detail, not only in the craftsmanship of his custom tubes but in making sure they’re going to do their job. He recently did a failure analysis on some of his high-end clocks that showed the same care for his product and his brand.

Thanks to [Chris Muncy] for the tip.

16 thoughts on “Custom Nixies Perform When Cranked Up To 100,000 Hertz

  1. I don’t watch youtube videos so I am not sure if they already answered this, but why not use a led clock? A normal scanning type clock obviously wouldn’t work, but as long as you have a dedicated led driver per segment LED clocks can easily refresh at a MHz and with a bit of careful work even up to a gigahertz.

  2. I’m missing something. It’s a display meant to be read by a human, where is the benefit to refreshing it any faster than the eye can see?
    I mean, beyond the “look what I can do” cool factor.

      1. Hmmm… I don’t think that’s better.
        The word “client” suggests this is a “paid for” solution, which means all the “Look what I can do” cool factor is irrelevant. There are definitely better/cheaper/more reliable ways to timestamp video.

        1. the customer wants to calibrate the high speed camera. I’m assuming that the VFD clock runs on an extremely accurate clock, and that the camera refresh rate will then be checked by taking images of the clock, and checking if the timestamp per frame is correct.

        2. “There are definitely better/cheaper/more reliable ways to timestamp video.”

          Indeed there are. For regular video, SMPTE time code is the standard. For high speed cameras, IRIG B has been the preferred standard. In both cases the time code is stored electronically, not by shooting video of a display that’s otherwise not connected to the camera. Time code is not used “to calibrate the camera” as some have claimed. Time code is used to synchronize disparate sources, such as a film camera and a separate audio recorder, or a battery of independent film or video cameras with remote telemetry data from an aircraft or missile.

          With cameras with digital video outputs, such as the one shown in the video above, each and every frame of video gets a time stamp that’s related to the digital stream or file format that’s being used. They do not need “artisinal” vacuum tubes to make the product work. Yes, it’s just a party trick.

    1. Now this is the kind of thing I come here for. Really love how Dalibor is doing a great youtube channel on what used to be s black art- making nixies. Never thought I’d actually see this information posted, figured it was lost to technological change. Really inspires me to make my own even more now.

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