Thanks for showing this under the microscope, it was illuminating! (pun intended :) ). I always salvage these from broken electronics and plan to use them in future projects. I've read that sometimes these displays can be "rejuvenated" (made brighter again) by momentarily applying a higher voltage across the filament.
cool presentation. So I wonder what kills these displays over time? Does the phosphor die or does heated cathode run out of electrons. I assume the phosphor dies first since you can lose a segment in a display, but other segments or digits are fine that share the same cathode wire.
The VFD on the stove at my dad's house was still working just fine when it was sold a few months ago. It might have been a little dimmer than it was when new, can't be sure. But that stove had been powered up pretty much continuously (except for power failures) since 1988.
8:18 When making the change from flowing one segment to two neighbouring segments, is the change only powering up the neighbouring grid without anything else? Asking because I want to figure out the internal wiring of the VFD. If the answer is yes, then the corresponding segment of all the digits are connected, and their glowing or not is determined by the grids in front of them. Thanks.
the electrons will travel from the filament to the grid, if there is a segment beneath the grid and that segment has a voltage on it, then the electrons will travel past the grid and hit the segment and the phosphor will convert the electron into a photon
multiplexing of digits must occur some how, so the 'bad' digit may be related to that in some way. they are interesting devices. I wonder what vacuum pressure is present. probably not very hard vacuum given the presence of the silver epoxy or what ever it is. and the close dimensions suggest a short mean free path requirement for electrons.
VFDs are electron tubes, so it uses high vacuum to work. The VFDs are often solderd together using as special solder glass, a low melting point type glass.
The silver stuff colors white when air comes in. Then there is too much oxigen inside. It also "eats" the last oxygen atoms after fabrication of the display so the oxigen does not react with other materials inside.
I really want to see someone test or explain the internal wiring of the VFDs. Such information would be much more helpful than merely doing some demonstrations without explaining what's behind the scenes.
I tried to explain all this in this video. I'm not sure what you missed. there is a voltage that causes electrons to travel and hit a phosphor. the wiring is that each segment has an electrical connection, so you can turn it on or off.
@@IMSAIGuy That's impossible if you say each segment has a separate connection (each will have an electrical connection of course). Simply have a look at how many INDIVIDUAL segments there are in a module and the number of pins that come out. Some segments must be tied together. My assumption for now is that all the segments in different digits at the SAME position are all connected. But I could be wrong; I'm on my way of figuring this out for a repair project that involves a VFD.
Thanks for the wiki page above. My understanding is correct. According to wiki, "All of the similar plates [which means segments or dots] in all of the digits (for example, all of the lower-left plates in all of the digits) are connected in parallel." If this is spelled out, everything becomes much clearer to me. Thank you for your help.
it is much like an LED display, in a digit, all the seven leds have a common anode and each segment is a cathode. so you have to multiplex the digits. in a 4 digit display, you have 4 anodes and 7 cathodes.
![แฟนแนวใด๋ - ยูริ โตเกียวมิวสิค [OFFICIAL MUSIC VIDEO ]](http://i.ytimg.com/vi/4_XVMuhhbsU/mqdefault.jpg)
Playing around with magnets around the VF-Displays also shows nicely how electrons are deflected :)
VFD's are probably my favorite display
Thanks for showing this under the microscope, it was illuminating! (pun intended :) ). I always salvage these from broken electronics and plan to use them in future projects. I've read that sometimes these displays can be "rejuvenated" (made brighter again) by momentarily applying a higher voltage across the filament.
Great explanation...never knew the details of how they worked, thanks!
HP used electrostatic plates for their modern 'scope tubes, not electromagnetic coils. How well I know. I used to build them. :)
A lot of oscilloscopes used electrostatic deflection, plus some early TV's.
I have several of these displays, I find them fascinating... You can make an amplifier if you have two VFD's.
people have tried that, one company made a actual tube with the technology , used in guitar amps
a fantastic triatic, on the technology of yester-year! they use that today, in light magnification.
I still have 2 VFD clocks. Not dimming yet. Nice presentation!
cool presentation. So I wonder what kills these displays over time? Does the phosphor die or does heated cathode run out of electrons. I assume the phosphor dies first since you can lose a segment in a display, but other segments or digits are fine that share the same cathode wire.
It's possible that the driver IC fails.
Maybe 20V was quite a HV for chip capabilities tens of years ago.
The VFD on the stove at my dad's house was still working just fine when it was sold a few months ago. It might have been a little dimmer than it was when new, can't be sure. But that stove had been powered up pretty much continuously (except for power failures) since 1988.
And you say you don't like vacuum tubes. :) VFD's are basically a bunch of tiny triodes in the same envelope!
8:18 When making the change from flowing one segment to two neighbouring segments, is the change only powering up the neighbouring grid without anything else? Asking because I want to figure out the internal wiring of the VFD. If the answer is yes, then the corresponding segment of all the digits are connected, and their glowing or not is determined by the grids in front of them. Thanks.
the electrons will travel from the filament to the grid, if there is a segment beneath the grid and that segment has a voltage on it, then the electrons will travel past the grid and hit the segment and the phosphor will convert the electron into a photon
@@IMSAIGuy Thanks for your quick response to my question. I understand all you are saying here. It seems like the answer to my question is yes.
multiplexing of digits must occur some how, so the 'bad' digit may be related to that in some way. they are interesting devices. I wonder what vacuum pressure is present.
probably not very hard vacuum given the presence of the silver epoxy or what ever it is.
and the close dimensions suggest a short mean free path requirement for electrons.
VFDs are electron tubes, so it uses high vacuum to work. The VFDs are often solderd together using as special solder glass, a low melting point type glass.
The silver stuff colors white when air comes in. Then there is too much oxigen inside. It also "eats" the last oxygen atoms after fabrication of the display so the oxigen does not react with other materials inside.
I really want to see someone test or explain the internal wiring of the VFDs. Such information would be much more helpful than merely doing some demonstrations without explaining what's behind the scenes.
I tried to explain all this in this video. I'm not sure what you missed. there is a voltage that causes electrons to travel and hit a phosphor. the wiring is that each segment has an electrical connection, so you can turn it on or off.
en.wikipedia.org/wiki/Vacuum_fluorescent_display
@@IMSAIGuy That's impossible if you say each segment has a separate connection (each will have an electrical connection of course). Simply have a look at how many INDIVIDUAL segments there are in a module and the number of pins that come out. Some segments must be tied together. My assumption for now is that all the segments in different digits at the SAME position are all connected. But I could be wrong; I'm on my way of figuring this out for a repair project that involves a VFD.
Thanks for the wiki page above. My understanding is correct. According to wiki, "All of the similar plates [which means segments or dots] in all of the digits (for example, all of the lower-left plates in all of the digits) are connected in parallel." If this is spelled out, everything becomes much clearer to me. Thank you for your help.
it is much like an LED display, in a digit, all the seven leds have a common anode and each segment is a cathode. so you have to multiplex the digits. in a 4 digit display, you have 4 anodes and 7 cathodes.
How many volts do you give to light up a sigment?
18
Is it a 5v or 0v ?
watch then entire video without skipping
Great explanation as always, good job. Hey if you need a new VFD for your SMU let me know and I'd be glad to send you one...
send me an email. you can find it here: th-cam.com/users/IMSAIGuyabout