SOME ADDITIONAL CONTEXT: I goofed here by not making clear that these wouldn't be naked in an actual product. They'd be placed behind a transparent panel, usually tinted which would reduce the impact of some of their worst flaws (however, I've seen some contemporary products which used these tubes and they're... better but still not great). Really, my issue isn't with the concept - it lived on much longer than the Numitron! My issue is with RCA's version of it: though pioneering, it wasn't very polished. (original pinned comment): Did you notice in some of the B-roll shots that they actually look more readable when they're slightly out-of-focus? That's the real downside of using segments thinner than a hair!

“Ignore all the continuity errors. It’s a running clock” Yeah not to mention the Krakatoa’s worth of lava lamps behind you

eBay sellers are going to be wondering why there's a run on Numitron tubes for the next 24 hours.

"Janky"...if I needed a "digital" clock in my aspirational Fallout-themed basement, I'd be happy with those.

"Numitron, take out Bumble Bee while I fight Prime" ~ Megatron 1972

Displays like this predated microprocessors by several years - they were typically driven by discrete logic or even mechanical switches. By the time microprocessors were a significant thing, LED displays were available.

<a href="#" class="seekto" data-time="751">12:31</a> Nice.

My mom worked the graveyard shift, welding titanium wire into grids, for the innards of huge radio transmission tubes, in 1941. She did that for a year. Tubes were used on ship-to-shore radio among other things. That's not directly relevant to your video, but I'm proud of her just the same.

I just loved the massive displays in Airports in the 70s and 80s which had flip over flaps for letters and numbers, and took bloody ages to roll over an entire line when it changed and made a racket doing it. The electronics that drove them must have been amazing. Dot matrix designs replaced them, now small screens all over the place does their job.

Numitrons were designed to be used with a filter in front of them. this solves the issues you talked about. they were very popular in avionics displays because they can handle extreme temperatures and vibration, unlike the other technologies (including early LED displays, which were unreliable). typically they're driven at a constant current (rather than a constant voltage) and, while turned off, fed a small current which keeps the filament warm without illuminating it. this makes the filaments last a very long time. The displays you remember from '80s gas pumps were Panaplex displays -- basically a flat 7-segment neon-filled display designed for multiplexing. they also show up in a lot of pinball machines from the era. they required high voltage, just like Nixie tubes. although they can't handle a ton of vibration, they work well in extreme temperatures (think North Dakota in the winter) unlike LCDs which simply freeze and stop working. modern gas pumps have heaters to keep their LCD displays warm.

I absolutely adore the colour of VFDs, the 'cooler' colour temperature to me just makes them look futuristic in a way when you make the comparison to the warmer temperatures of other displays that feel retro.

I can tell a little about Soviet numitrons (IV-9, IV-10, IV-13, IV-14, IV-16, IV-19 and IV-20). First of all, I am not sure that they were clones of RCA products, because I met them in industrial equipment produced in the mid-1960s. Secondly, the IV-9 and IV-16 were actually quite light, and the barrel-shaped moulding of the leads was done only to prevent the glass cylinders from cracking when heated. Thirdly, with 400 Hz pulse power supply (in aircraft applications), some of the tubes started to "sing" due to resonance - as a rule, this meant that the tube would fail within the next 100 hours. By 1977 such indicators were considered obsolete and were not used in new developments.

Numitron backing is grey because RCA used what they had in spades, the sheet steel with aluminium coat that was used to make anodes and internal structures for thermionic tubes, and this was proven to survive the glass sealing and gettering operations. Thus they used the standard tools they had in the tube plant, the flat anode sheet, slightly formed to be a stiff backing, and punched out the holes needed to hold the filaments. Then used the technology they had to make glass beads with wire in them, and sealed those into the holes, making the filament supports, and then simply used a flat section of that steel wire that was bent over to hold a length of thoriated filament wire, also a common item in the tube shop. Length and diameter calculated for the brightness needed at the applied voltage, and then simply placed in location, the ends folded over, then spot welded together to trap the tungsten wire under slight tension. Then at the rear spot welds to a lead frame attached to a standard off the shelf 9 pin glass base, and you have the complete unit. Glass top attached, and then evacuated with the standard roughing pump, and as a bonus because of the low voltage, and no need to maintain an ultra low vacuum, the roughing pump and the heat sealing of the tube is all that is needed to operate, no need for a getter to be installed, and no need to flash it, just a RF heating during sealing to get a high vacuum, then seal. Incidentally there were small versions made, the same size as your common 7 segment LED displays, and they were very popular, as they ran off 5V, and interfaced with logic. They worked best using CD4049/50 CMOS level shifting buffers, as those would source or sink 50mA no problem. Using a buffer/inverter per lamp, and a BCD decoder or counter per digit allowed those displays to be bright, and as bonus you could also use the blanking input on the drivers to use PWM to dim them. Project to replace those displays with LED ones worked, just that it really did not drop display current use, it was still 5A of current at 5V, though it was good in that at least you had a display that now was available, using a tiny HP 7 segment red display. Do one conversion and you had 16 numitron displays to use to fix others, so we only converted 3 boards to the LED version. Biggest problem was the resistor value selected was too low, so the LED displays were running way too bright, so had to be dimmed. Rather than destroying the cordwood board made to fit them, I simply used 2 6A silicon diodes in the common line, to drop the voltage seen by the LED displays down from 5V to 3V8, which made them dim to exactly match the old displays. Those 2 diodes were hard to fit in the limited space left on the display board. Users liked the new crisp displays, the bright version got complaints that it was so bright it was unreadable at night with dark adapted sight, and it lit up the entire cockpit. Display dimming had to match the other display, and that board used unijunction transistors, and had a disconcerting habit of the power transistor unsoldering itself from the wire leads, it ran so hot. Base lead unsolders itself, transistor is still conducting, runs hotter and lamp blows. Select spare lamp and it also blows, unless enough time for transistor to cool below 200C junction temperature. Would have been nice to have had some of the more modern mosfets that can handle 50A, but not at the age of that design.

Numitron to me looks pretty dope. Elegant thin numbers, the amber glow, the smooth transitions between on and off state of each line. Everything - almost perfect design.

Alec, I am just a middle age hard working hillbilly from the mountains of East Tennessee, but I want you to know that I appreciate you. We are very different people, but probably have tons in common. Thank you.

These displays give me a warm fuzzy nostalgic feeling. When I was a kid, the ticket machines for our public transportation system used Numitrons to indicate how much money you need to put into the machine. Good old days...

I love the VFD, it's such a cool design and 80's and 90's devices looked cool because of them.

About 20 years ago I sold a few NOS Numitrons via eBay to a guy in Germany who made clocks with them. I was a bit shocked that he paid to have them shipped international even though I couldn't guarantee they worked.

The Spaceship Earth reference at <a href="#" class="seekto" data-time="121">2:01</a> didn't go unnoticed! Masterful work, as usual, that made my day. 😁

In a million years I did not expect to see the K155ИД4 in this video. That brings some memories

"Now, I'm about to be rather unkind to this piece of alleged technology," he said after basically calling it a piece of shit

There's something beautiful about how old technology worked. The combination of the limitations of the available electronics and engineering of the time resulted in some unbelievably wild ideas making it into every day products.

Massive kudos on Aligning the times between the different footages!

I love the Numitron clock. The warm, gentle light, the slow transition of the numbers, the beautiful glass envelope. So easy on the tired eye. It’s the best bedroom clock ever imho.

I like how you spent the entire video trying to convince us how bad the Numitron was, but only managed to make us fall in love with it

Numitron looks great too me, even with its flaws.

It might not scream quality, but it screams cool retro in a Brazil film style

I find your content informative and your outtakes amusing. Please keep up the good work.

I think they look quite good, I'm a fan of how they fade in and out as well when changing numbers.

I would argue that "bringing the simplest possible solution to the marked when it makes sense" is actually a good arguemnt. Because then it makes sense. Espcecially when you know that a better alternative is already around the corner, but not quite ready yet.

The way the segments fade on and off is beautiful, peaceful, soothing, like a flame. Speaking of flame, perhaps you can make a clock of fire.

I will grant it this. When filmed, these look like an animated version of the time stamp impressed on disposable film cameras, which is a deeply nostalgic and happy aesthetic to me, so I feel nothing but good will for then when filmed from afar

I think an underrated aspect of TC’s writing is the use of “we” instead of “they” when talking about technological advances in the past. Makes one feel more connected to humanity’s technological past.

Your memory is correct about the flat packs being in gas station pumps. I remember as a kid seeing them as well, always thinking they were pretty cool. They usually had a smoked cover over them though so you couldn't really see the pack, just the light emitted.

As a retired Analog Design Engineer in the 70's, I enjoyed the history of numeric displays. I still have plenty of them in my junk boxes.

Fantastic stuff. I think they look lovely and warm in low light.

I loved the glow of the “Nixie Tubes” on our old frequency generators and counters years ago in our darkened radar van. The hum and glow was mesmerizing and I found them beautiful.

Aside from nitpicking about the manufacturing quality, these actually don't look half bad in the video. They're completely readable and clear in the lit-up wide shots, and the fuzzy outline around the segments (from the much hated gray background) in the dark gives them a nice soft look

I did a report in school during 5th grade on these sticks.... I did get an A on it to!! Glad to see you made a video on something so simple but elegantly pulled off

<a href="#" class="seekto" data-time="751">12:31</a>. I have to rewind to make sure I was seeing that right. Love the detailed touch there

you're clearly correct about all your technical objections but also "jank" is my absolute favorite thing in any appliance or machine ever and i love them. what wonderful little freak bulbs

They’d make a great prop for a steampunk themed display though.

This channel gives me joy, and info.

Last night I felt a disturbance in the force and watched your videos feeling like another video was about to be uploaded, I’m glad my senses were right

"Oh Hey, LEDs" I seriously lost it at that point. Thanks I needed a good laugh.

Back in the early 80s, the aircraft I worked on in the Navy were full of Numitron displays. They are surprisingly rugged and long lasting given the vibrations and forces they have to contend with in avionics applications.

Your beautifully petty attention to detail and dedication to snarky easter eggs is appreciated.

Thank you for promoting Fran. She is a gem and is a very underrated channel!

I"m so so annoyed that the 5 in Nixie tubes is just an inverted 2

Excellent as always, Sir.

<a href="#" class="seekto" data-time="1205">20:05</a> Thanks for the shout-out to Dr. George Heilmeier. He was a University of Pennsylvania and Philadelpha legend whom I actually had the honor to meet and serve with on a board at Penn. Rest in Peace, George.

I just wanted to say that there are few channels I get this excited for new content. Thank you for being you.

There's something charming about these old displays

I know the guy who did the first 7 segment LEDs for RCA. He designed them and worked out the production of them. He worked there in the 70/80s. He has an extreme case of OCD. He is retired, and I have been to his apartment, and he has 10's of thousands of little electronic parts all organized on shelves in little bags with numbers on them, and he has the all inventoried in a database, so he can find them, and he still builds all kind of electronic projects. He lives in Springfield, Ohio. I met him on the Ham radio repeater.

Well presented. Great topics. Keep them coming.

You are put of your mind! Those devices are GORGEOUS. I love the thin segments. I love the slight overshoot of the vertical segments. Wow, I want one. I want a lot I also want to build your huge LED clock, on a rollable fabric

I've never felt so sad for a glowing tube until you really hammered down on just how bad they are

These are visually beautiful.

The way the filaments heat up and cool down gradually makes it look insanely smooth as it transitions from one digit to another. Gosh I want this clock NOW

I have a X-Y digital readout for my milling machine that I got for free in the 90's because the flat pack incandescent seven segment displays were failing. Friends and I upgraded it to LED's and it still works to this day. Thanks for this wonderful history lesson! I never knew they made them in vacuum tube shapes.

Maybe this was not a popular product in its day, but that clock looks cool AF.

Speaking of early LEDs being expensive: When my father graduated from college in 1974 and embarked on his career as a mechanical engineer, he went out and bought himself a brand new Texas Instruments SR-50, one of the earliest handheld scientific calculators (back when they were still called "electronic slide rules"). It had a 10-digit LED display and cost $170 (ca. $1,150 today), which was reportedly more than he paid for the car he was driving at the time. Obviously not all of the SR-50's cost came from its display, but even so, it's illustrative of how pricey microelectronics were at that moment in time. A mere _two years_ later, the very similar TI-30 cost all of $25.

The quality of your research and writing is ridiculously impressive. I often fail to notice this because you're so damned entertaining!

I love how janky they are, As a product designer myself, I bet the people working on these had a blast designing them, the sheer "slap stick" energy they radiate is just amazing, the pins also being the only support for the internal board (no wonder it's all crooked), the tape that hides the back wiring wrapping around the front of the board, the barely stuck in needles holding the filaments, and the cheap gold paint on the even cheaper metal rings around the base of the bulbs. My only real critic would be the background, it doesn't look like it's made of anything special, they could have easily just picked something darker. It's a shame they were hidden behind tinted panels, at least make the panel transparent to show off how cool they look !

Posy made a great video about segmented displays if additional viewing is desired :)

Nice work!

I recall seeing numitrons in British petrol pumps in the late 70's. As a geeky kid at the time, I was always facinated by them.

We never used Numitron tubes, but there was a period... roughly 20 years or so, where we were using (red) LED 7-segment displays and matrix displays. The matrix displays were really cool, basically they were just a rectangle (similar to a 7-segment digit), but each "digit" was a matrix of point-source LEDs. For example, 8 x 7. The matrix displays could be used to produce very legible alpha-numeric representations, including lower and upper case. And if you stacked a couple next to each other you could produce a scrolling display. Actually, you could produce a scrolling display even with just a single digit and output perfectly legible sentences that humans could easily read and understand. While you could produce an alphabet with just 7-segments (and even more with 15-segment displays which were briefly a thing too)... while you could do that, you could not produce and distinguish every individual letter in a way that a human could naturally read. The digital drivers for these displays were really easy to make. You literally just have a direct digital output for a single column and then you have a demultiplexer chip to select which column to drive. The power required was small enough that HCMOS logic could directly drive the columns. In anycase, for 7-segment, you needed 8 digital outputs (including the decimal point "."), plus one open-collector output for each whole digit. A very small number of digital I/Os could drive many digits. Each digit was driven individually, time-domain multiplexed. For example, you drive digit #1 for 1 millisecond, then you drive digit #2 for 1 millisecond, and so forth, repeatedly, to drive the whole display. One very interesting consequence of doing this with a CPU (like a 6502 or a 68000 in those days), and having a 1ms timer interrupt, was that your main loop could not disable interrupts at all because the timer interrupt had to be very precise or the human eye would pick-up the distortions in the time-domain multiplexing of the digits. One segment would be displayed slightly longer and appear brighter (even just 20 microseconds of jitter was enough), other segments slightly shorter. There were 7-segment driver chips that took care of the timing, but it was cheaper and better to drive the displays directly from a CPU-controlled digital I/O because you could do a whole lot more with the display with direct CPU control. -Matt

The always-conservative aviation industry has used these for far too long; I believe some of them are still in use today in 737 NG IRS panels

I'll be honest, I love these. I love how they look so much, I thought there was some other inherent issue with them that you were going to expose but then you didn't. Thanks for introducing me to this amazing lil piece of retro technology.

This tech was widely used in aviation for clocks and other displays. It was smaller, and I cannot remember if it was called Numitron or not. (Edit: Minitron is their name.) They are usually put behind a filter screen, that makes them easier to see. Simular to how VFDs were used. That eliminates one of your biggest gripes. You don't see the background, and contrast is much better. I have several of these old aviation clocks and a few new tubes sitting around. They are small squared off devices that slot in similarly to an IC chip rather than the large tube. The old clock was a Davtron M811B and they have newer versions, the M850 and M877. I have several of the 811B and 877s. The tubes in the 811 are larger, and have that look of being electronics manufactured mid 20th century. The 877 has tubes that look more modern in construction, and it looks like the M850 uses the same tech from what I can tell. Funny thing is, it apears you can still buy the M850 new, and they cost about the same as a single replacement tube assembly for repair. $400-500, depending on the source. You need to buy traceable parts for aviation, and that makes them expensive. Plus the low volume of manufacture and sale. They don't tend to burn out often, I have only replaced a few.

It sounds as if they put exactly the right amount of effort/money/time into this product, for the limited amount of time it would be relevant. If they had done it better, would it have lasted longer on the market? Probably not.

love learning about this as a designer because it's an example of visual design having a big impact on technology

I love some fresh new nerdy video about something I never thought I'd want a deep dive on

I can confirm these were Indeed popular on gas pumps probably around the '80s iirc.

My dad's old 7 segment display alarm clock has a system I've not been able to find any info about. When it finally broke he let me take it apart and it had two sheets of glass for each number with black stripes. Thr sheets were connected to a wheel with grooves in it. As the wheel turned, it caused the plates to slide and the stripes would line up to form the numbers of a display. We were quite surprised it wasn't just some sort of back lit LCD.

I just saw a cool video on this earlier! Cool to see another one

<a href="#" class="seekto" data-time="752">12:32</a> Thank you. I was waiting for it, and I was not let down. 😂

Dangerous?! Edison told me DC was the safe one and it's Westinghouse's AC I should worry about. So I will stick with the Nixie tubes thank you very much.

I adore the Nixie style displays, and these are close! A great video as always, my friend.

<a href="#" class="seekto" data-time="63">1:03</a> I love mechanical segment displays so much, there's just something kind of soothing about watching them change.

Wow .. they are BEAUTIFUL !

<a href="#" class="seekto" data-time="3">0:03</a> hell yeah, the pope hour

Awesome! Finally caught a video during the daytime instead of finding the video 5 minutes before bed

So cool!

Growing up, I remember my Mom having me practice math problems on "The Little Professor" hand-held toy. If I remember correctly, it didn't have an LCD display, but one of those early LED displays with the tiny thin lines.

I honestly LOVE the way they look, especially in the dark, so beautiful

1.5 minutes in and I'm commenting - what made the Numitrons nice was their reliability, very low voltages needed, and 100K hour life at low cost. VFD tubes lasted about 1/4 as long as Numitorns even if they were more efficient.

in the late 80's my mom worked for a local fuel company that had a chain of gas stations and the one she worked at had some of the first electronic fuel dispensers that Tokheim made from the late 70's and it used these damn tubes. Constantly had to replace the tubes as the segments burned out in them, you couldn't see them in the daylight, and they were slow to update. She was so happy when they ripped those dispensers out for newer Wayne models with LCD displays.

Nice presentation and info

I don't know why it bothers me so much that an 8 doesn't need 8 segments to be displayed.

<a href="#" class="seekto" data-time="1344">22:24</a> Thanks for tending to the OCD-side of your audience. This benefits us greatly.

They looked great on camera. Great work making them look good.

Don't listen to the mean guy, Numi, you're beautiful!

Your channel is a gem.

There were other incandescent 7-segment displays that looked like flat DIP devices with a glass plate on top and DIP pins on the bottom. (An ebay search today shows a few.) I remember it was a stocked part at Radio Shack in the 1970s.

You light up my life.

This was Technology Connections video I could relax into like a comfy armchair.

I loved the dig at RCA at the end! :)

Don't forget that a slightly tweaked 7 segment display can create a very recognizable image of Sting, Stewart Copeland and Andy Summers.