A couple of years ago (yes, years) I was given an IV-11 VFD tube. VFDs are a class of tube that is less popular among hobbyists than the more beloved orange Nixie tube — although they are often mistaken for them by newbies.
Having no idea just how to drive the tube, I dropped it into the bottom of my Nixie parts bin (ironic, admittedly). There it languished until about three weeks ago, when I decided I needed a weekend project and would like to try and build a circuit around it. Step one was to figure out if I could light the tube.
Fortunately, the ever handy Dieter’s Tube Archive had a translated datasheet. Important because the tubes are surplus from the Soviet Union, meaning that the original datasheet was in Russian!
With a datasheet in hand, I knew the voltages and currents needed, so I was off to the races. Taking the pinout from the datasheet, shown below,
I switched on my two trusty benchtop power supplies (both are single output), set my voltage and current limits, and was all set to go… or so I thought.
Here’s where reality and the datasheet collide. The datasheet says there is a “short pin 12”. In reality, there is no pin 12 at all, just a gap. Alright, that’s a warning sign, but not the end of the world. The gap however, means that the datasheet view of the bottom of the tube has the rotation at about 45 degrees. It also took me some time (and observation of the internal construction of the tube) to determine that this pinout was a bottom view of the tube, not the top. To save the rest of you the time I wasted making heads or tails of this, here’s my IV-11 pinout.
To finish my testing, I simply connected the appropriate anode segment to 25V to light it. I was going to include a picture here of the VFD lit this way. Thing is…I didn’t take a picture of it lit back then, and when writing this post, I managed to blow it up by swapping pins 1 & 2 with my alligator clips. On the plus side, the filament made a really bright lightbulb for a few hundred milliseconds. Oh well, they’re only $3/ea on eBay from the US. Way less if I’m willing to wait for shipping from Russia. At this point, I’m invested enough to buy a couple more.