EEVblog 1601 - How VFD (Vacuum Fluorescent) Displays Work 

I love that teal green glow of VFDs! When I realized they were beginning to go bye-bye I began hoarding as many NOS VFD modules as I could get my hands on. Have a pretty good stockpile now!

I know VFD's are considered an obsolete tech now in the face of OLED/LCD etc. but that signature blueish-green glow and the magic of them being a hybrid tech somewhere between a Vacuum Tube and an over-simplified CRT keeps them in a special place in my heart.

One of my first jobs was designing a driver board for a VFD. It was just a rig for testing the displays in isolation. Once I realised they were basically a triode, I messed about and built a low power audio amp out of one. Linearity and voltage gain was awful, but a fun thing to do. I do love VFDs. Some modules that have on board drivers follow the Hitatchi protocol for comms. So you can use them to replace simple 2x20 type LCD modules. To make stuff look so much better.

I always loved VFDs.. on every stereo and VCR in the land

I really miss these. The dash and center console in my car use the old-school green segment and dot VFDs and there is just something really nice about them.

Can we please bring back the OG EEVBlog style of videos? Dave talking next to a whiteboard for half an hour or so in a fundamentals friday video?

These VFD had a very pleasant display. One application was a multipoint printout paper chart recorder. The VFD displayed the analog values and alarm messages. Then came the computers and machine PLCs. Technology keeps moving on. 😎 Thank you for the trip back in time.

One thing to add, some filaments can have quite a bit of voltage drop across them. This means you have a voltage gradient and the electron to anode voltage varies. Some controllers use AC on the filament to help that. On my board i just compensated by changing anode duty cycle

Great video and well in depth on how these VFD's worked. I often remember seeing these displays on cash register systems before going with LCD displays.

Those VFD displays sure could be any shape you could imagine. Back in the late 1970s to early 1980s, there were quite a number of electronic games with such displays. I had a boxing game like that, just think of a typical Tiger Electronics game display but instead of the LCD, everything was a beautiful glowing green.

Thank you Dave! I was just thinking about VFDs a couple of days ago and I figured they were some sort of miniature neon tubes, but I guess I need to watch your video now and see how wrong I was!

VFD by far is one of the coolest display technology out there.

VFDs look awesome! I use them everywhere I can instead of leds.

Not event halfway through this video, but this is wonderful! VFDs have such a nostalgic and comfy feeling; the colors, the brightness, the way they can be so dynamic. It's amazing Every time I browse DigiKey, I find myself drooling at all of the Noritake VFDs, but jeeeeeeeeeeez they're pricey. Argh, I want to build some projects with VFDs :(

Huh. Saw the thumbnail and thought you were going to be treating down a Variable Frequency Drive. That would make a fine video. As far as vacuum fluorescents go, i never realized they were effectively an array of triode tubes. I wonder if you could use them as such and build digital logic using the display as the switching elements.

blast from the past!.... and great timing too... i just ripped a VFD out of an old stereo i wanna hack (its still on the pcb with the driver) ..these things work pretty much the same as vacuum tubes..

I worked in Point of Sale / Industrial Hardware when they switched from VFD to LCD to show amount of money and other stuff. The biggest problem was (is) the brightness+contrast.. What do you need to show: a number, money to pay. Now they are showing all kind of stupid stuff, logos and ads and somewhere on that dim 10inch lcd is the money.. until it fails or the windows driver screws up. (VFDs were mostly simple serial port with special symbols for ASCI/countries)

I learned the hard way that VFD's and 7-segment led displays aren't the same. It must've been 1998 (i was 8) when i couldn't get a VFD to work so i just turned up the dial on my DC lab power supply. Those tungsten wires glow BRIGHT! ...for a short time.

Subaru legacy 2004 (UK) used them as dashboard displays (time / date etc.) And yes - it failed before the engine :) Well..... display was fine - just a resistor behind the tube desoldered itself. Still - VFD > LCD just coz they're cool!

Oh god I looove VFD! I own a lot of music equipment mostly because it's got a VFD display (various Ensoniq samplers, Yamaha SU700... 😍). If only they weren't so hard to replace.

Ah, thanks to this explanation I now understand how they work; they're more like lots and lots of mini TVs!

My AV amp has a large VFD and when on standby the cathode heater is on all the time. Can see it slightly glowing in the dark and makes the front panel warm to the touch. Even though no characters are lit. You would think it would turn it off if no characters are lit.

Great! I knew you could do it! 10 minutes! Even with several bloviating minutes in the beginning, this is a Gem! Do more! Thanks

I miss these.

An oldie but a goodie.

I suspect that is a spare part for a supermarket type cash register.

They really are nice to look at. Interesting to see just how they work too.

I like this vintage of Dave

One of the first electronic devices I ever took apart as a little kid was a Texas Instruments "Speak & Read". The VFD in this video looks to be the same design, same grey seal/gasket, same cathode wires.... yours just has more characters. And, I see a bunch of Ti chips on that board!

VFDs were so beautiful in old handheld games.

Always loved VFDs, specially the ones that powered shelf stereo/mini systems displays. My old Sony MHC-DX7 had one and the spectrum visualizer was very crisp, colourful and fast, I miss it so much 😢.

Not sure if you've seen it, but Korg (edited) has made a dual triode VFD based 'tube' they are selling. Yes it's just a VFD they are using for audio (it's also microphonic) and thus insanely expensive for a VFD. But, maybe it's worth a look and a chuckle. It's called the Nutube.

Thank you.

I love the VFD display; I hope it will be the same case as with Nixie tubes, i.e., there will again be some companies producing those displays in the future. The current stock is getting small and overpriced.

Nice displays!

OMG I ❤ VFDs 😍

i love your video a lot thanks

I think VFDs were at their peak in the late 90s early 2000s when the mini stereos were extremely popular- you'd walk into an electronics store and were dazzled by all the dancing VFD displays in demo modes on like 30 mini stereos. Great times!

Would be neat to repurpose the VFD from a VCR or something to make a fancy clock. Upcoming project video?

My 300zx z31 has vacuum fluorescent displays for the entire dash. Its cool seeing tho whole dash light up.

Dave have you taken a look at the Korg Nutube? it's basically a VFD but used for audio applications.

The VFD's is the reason my favorite Bench Multimeter is the HP/Agilent 34401A and my favorite lab PSU is the HP/Agilent E3631A

It sounds like you are suggesting the grid is the control for the illumination. If that were the case different parts of the grid should be chargeable. I am not familiar with it but what may be happening is connecting the pads in circuit may be what is making them illuminate. That is otherwise they just charge up like caps and stay that way. Maybe closing the circuit lets them discharge sporadically and thus the electrons go down shell levels and emit light?

Looks like a display for a Pinball Machine

Could you do a video on FED / SED displays? They never became mainstream but the technology is super interesting

I have a VFD almost identical to that one. I believe it came from some sort of a network printer (can't remember what I pulled it out of). I tried on and off for years to get it to work, but could never find any documentation on the driver chips installed on it. I still have it somewhere. One day I'll dig it out and have another go. Would love to get it up and running.

Ripper .. these things were cool in the day. Ovens MW and I R, used them extensively, too.

Nice explanation. I've built a clock with a IVL1-7/5 Soviet VFD and MSL912 chips as drivers, but I'll want to try driving the tube with something more common like ULN2003 / 2803 with pull-up resistors and some inverted logic confusion. BTW, did you know that the overhyped Korg NuTube is basically a single-segment, single-position VFD made for them by Futaba? Now you know, haha.

Dave looks a bit younger in this vid: congratulations

I've heard you can use these as little audio preamp tubes... If I knew what I was doing a bit more I'd try it out. Maybe I should try it out anyway... Peace.

You can drive VFD with bog standard TTL gates, just have to use those with 30V capable open collector outputs, and use a lot of pull up resistors. Though many clock modules would operate perfectly fine using the automotive 12V supply, with many just using a simple resistor voltage dropper to get the filament drive, often clamped by a 3V zener diode just in case. Chip driver ran off 12V, generated with a zener diode and transistor off the battery voltage, driving the tube directly, and containing all the clock and oscillator, with dimming being accomplished by dropping the supply voltage, using a single transistor to short one of the 2 zeners in series used to power the chip. Those displays ran for decades. Plus a lot of early white goods used them to provide a clock display, running as a module in the back of the stove or oven, and it was there to provide just a timer and a delayed start, or to turn off the oven after a set time. More pages in the manual given to set the clock, run the timer, and set the automatic functions, than devoted to the entire rest of the control panels. You also had them in fuel pumps, though that has now almost entirely been taken over by LCD displays, though a few still use them for the maintenance display in the front. Open some of them and you will still see the original mechanical display there, left in when they got converted to electronic, as that simply bolted together around the existing pump frame. Others just the shaft sticking up, with the original pre WWII positive displacement pump clunking along in the bottom, refurbished every decade or two with new seals and rotor vanes, plus new bushes, and then calibrated and put back into service.

For those in Australia wanting to have a play with a VFD, Jaycar sell an 11 digit display for only $2.95 ( Cat No: ZD1880). Not available online but stores have plenty of stock.

So, how much current would one need to supply on the 20/30/60 volt line? Can you manage with a voltage multiplier? Or do you need to have a seperate power supply tap of like of a transformer.

I've just got one Lauer PCS900 HMI from '94 with nice wide VFD similar to one in the thumbnail

Old Dave even sounded different, more professional, calm and straight to technical point, not that modern yootoobie sensational way.

Amazing video dave Can you please do a video explaining flip flops and encoder and decoders

Does anyone have long-term experience, which filament voltage is the best for longest life? When the datasheet says i.e. filament voltage 2.4V +/- 10%, should I use exactly 2.4V or go down to 2.16V?

When did you upgrade to DaveCAD 3.0?

How reliable, or lifespan of these VFD, in comparison to LCD type ones?

they look amazing despite consuming a lot of power

Oooooh this sounds cool

Posy likes this :)

I wonder what the D in VFD stands for?

Korg is using this same VFD tech for triode substitutes in guitar pedals. I don't hear enough difference between their NuTube pedals and similar pedals with bog standard small signal diodes to justify a higher pricetag.

7:59 you can see the burn in on display

Most of these VFD are custom design for each application. The one in my stove is already weak I will have to scrap the stove because it is unavailable.

I need to know something important not addressed how much power does the filament draw. 3 3v ac at how many amps

Hi Dave 😊 you the best 🎉 hi from Ukraine 🇺🇦

New BK Precision test kit appears to still use VFD for displays...

Although the 2x20 or other variations of LCD can be a replacement for VFDs, when it comes to visibility from a distance VFDs are hard to beat. That, and if you had to use an OLED display to replace the VFD it would incredibly expensive, even for a monochrome OLED. They're only really cheap in extremely small sizes, and to replace a VFD like Dave demoed it would cost a ridiculous amount for a comparable OLED of the same size. Now when it comes to power dissipation that's another thing entirely...

They fade overtime... But they are gorgeous!

I want to put one in a project

i love vfd displays

do nixie tubes next!

Vacuum Fluorescent Display Displays. Best title for best looking displays

Very much enjoying my Suprim X 4080 Super having got one to replace a dead 2080ti 😊 - I have 60hz 4K monitors atm so for now I'm enjoying the silence at 200W or so 😂

VFD's are great. My 90's hifi system has them but they are starting to fade now

6:20 - I believe (and this is REALLY gonna date me!), TTL Open-Collector Drivers! (I'll show my way out...)

I like the VFDs because they are easy on the eyes.

It's not really that hard to build a driver for a VFD. I've build them for plenty of salvaged displays. I just use a high voltage shift register to drive them. I wind a small transformer for the filament and drive it with a small H-bridge IC and use a boost converter to supply the anode voltage. It's pretty easy to figure out the pinouts since you can see a lot of the connections through the glass.

Vacuum Fluorescent Display Displays...

👍👍

Next up "How VFD (Variable Frequency Drive) works"? :)

That was a really abrupt end to the video.

Did anyone ever make these in other colours than green? (an orange vfd would look fantastic!)

I used to reapir cash registers back in the late 90s and early 00s. Once we got a call from a client that the display is sometimes doesnt work. I thought it will be an easy job. nah! the cash register was full of cockroachies.

I think it's possible to make VFD display in "garage" conditions, not so hard... People make their own Nixie tubes at home, at least 🙄😀

cmon dave, these are proper oxide cathodes coated with barium and strontium oxides, not simple tungsten wires

Why does 50p still exist this day and age for filming? Every TV regardless of location can do 60Hz so why are we still dealing with 50Hz?

*Promo SM* ❣️

7:30 Very good 🃏🧭🌨️🕯️😡💤 ground to Air , WiFi Live longer.Fountian or Youth.

That explains how they can put These on your Skin , Electic Skin Time for a Up Grade,

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