Neon Lamps — Not Just For Pilot Lights

It’s easy to see why LEDs largely won out over neon bulbs for pilot light applications. But for all the practical utility of LEDs, they’re found largely lacking in at least one regard over their older indicator cousins: charm. Where LEDs are cold and flat, the gentle orange glow of a neon lamp brings a lot to the aesthetics party, especially in retro builds.

But looks aren’t the only thing these tiny glow lamps have going for them, and [David Lovett] shows off some of the surprising alternate uses for neon lamps in his new video. He starts with an exploration of the venerable NE-2 bulb, which has been around forever, detailing some of its interesting electrical properties, like the difference between the voltage needed to start the neon discharge and the voltage needed to maintain it. He also shows off some cool neon lamp tricks, like using them for all sorts of multi-vibrator circuits without anything but a few resistors and capacitors added in. The real fun begins when he breaks out the MTX90 tube, which is essentially a cold cathode thyratron. The addition of a simple control grid makes for some interesting circuits, like single-tube multi-vibrators.

The upshot of all these experiments is pretty clear to anyone who’s been following [David]’s channel, which is chock full of non-conventional uses for vacuum tubes. His efforts to build a “hollow state” computer would be greatly aided by neon lamp circuits such as these — not to mention how cool they’d make everything look.

30 thoughts on “Neon Lamps — Not Just For Pilot Lights

  1. I keep thinking about making a lightning detector, and remember I’ve got an NE-2 somewhere… then I can’t find it… then when I’m busy with something else, I find an NE-2 and remember I was gonna make a lightning detector, so put the NE-2 “somewhere safe” whereupon it dissappears… repeat x10

    So yeah, just really meaning to mention that NE-2s do something cool that LEDs can’t …. sporadic macroscopic quantum teleportation.

    Okay, it was lightning detection really, you got me.

    1. From your Wiki link: The term “pilot light” is also used occasionally for an electrical indicator light that illuminates to show that electrical power is available, or that an electrical device is operating. Such indicators were originally incandescent lamps or neon lamps, but now are usually LEDs.

  2. Easy does it. Like everything else these days there is a Neon shortage:

    * The war in Ukraine is disrupting the world’s supply of neon

    * Ukraine supplies 90% of U.S. semiconductor-grade neon (and what it means to chip supply chain)

  3. “Filament LEDs” are inexpensive and look like a traditional filament, except that they are available in a multitude of colors. Several are pretty small, most of those are low voltage, and some are even flexible.

  4. My first lab bench power supply is a linear affair that uses two neon lights. One to indicate mains voltage is connected, one to signal it is turned on. The neon lights were salvaged from a broken washing machine, somewhere in the mid eighties, when I first started dabbling in electronics. Next they were stored for over thirty years before being used again. Talking about keeping things out of landfill!

  5. I remember the stories of how complicated was the maintenance of old tube computers due to tubes burning out. Given this neon bulb don’t have filament, and have pretty stable gasses, how reliable a computer would be? how long does it takes to burn one of this?

  6. Neat demos of circuits I haven’t done much with in a long time, but I agree that a little more explanation would have been nice, for those that have never seen these circuit before, and for those of us that haven’t looked at them in a long time. Or maybe that would take away the fun of working the operation details out as a puzzle?

    I’ll note that the instability in the trace was not due to the scope triggering, but due to a small bit of frequency modulation. If I were to guess, the HV power supply has a significant AC component.

  7. The applications for sensing magnetic fields, electromagnetic waves of fairly high frequency and certain subatomic particles, is an interesting subject of it’s own.
    HaD has covered a few projects using neons over the years.

    1. I don’t know an application for this but I thought it was pretty cool that if you bias an NE2 to just below where it’ll glow, you can turn it on with a laser diode. It’s like a geiger-muller tube for light intensity.

  8. There’s still a lot of these around for the picking. A lot of switches had neon indicators and “analog” alarm clocks used them for illumination. They used very little current and therefore generatred little heat.

    The neon relaxation oscillator was one of the first circuits I built in the 60s. I also recall that if you connect an antenna of some sort to one lead (I think i taped it to a metal pan when I was a kid), you can go into a dark room, hold the pan’s plastic handle and light up one electrode by touching the other lead. The 60Hz radiation is enough to light it.

  9. He also has an entire series dedicated to restoring a vintage Centurion microcomputer. He actually gets some help from a former engineer and has to reverse engineer a few cards to figure out how to restore the OS. It’s worth a watch.

  10. ne-2’s remind me of the old “idiot box” kits beginners would put together. A square-wave battery power supply, a doorbell transformer, and a handful of ne-2’s, resistors, and capacitors — and you can have as many blinky lights without a 555 as you wanted.

  11. I don’t see the point of this channel – it looks like someone keeps buying heaps of vintage stuff just to show them off on Youtube, make vacuum tube computers and neon bulb flashers and flip-flops for himself and be really excited about it and make money, but there’s no educative side of these videos. Wondering what he’s trying to create (I just find it irritating that heaps of vintage stuff goes into the trash after a youtuber made some videos of “wow, how cool is that, I’ve made one bit of memory from two 6BA6 tubes”).

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