In his world wide travels, LegionLabs picked up a little vacuum fluorescent display showing micro, amps and volts. Definitely a unique souvenir! I'd never worked with VFDs before, but in the end, they are quite simple. A hot filament emits electrons, which are evened out by a grid and then impact on fluorescent surfaces. They run at relatively low voltages, as compared to, say, Nixie tubes.
The leads are pretty easy to figure out just by examination. I followed the directions here and pretty quickly had it working.
Heres a zoom out on the setup. On the right is a slapped together bench supply, using an LM315. Its running the filament at 1.24 V, with no limiting resistor. This is pulling 35mA, on start up it pulls quite a bit more (~50), but it quickly reaches temperature and stabilizes there. In real use, I may try to reduce that current a little.
I have no idea why there are so many leads on the tube. Theres only the three elements inside (micro, V and A), each element is connected to several leads, but they dont seem to be lighting up different parts - they are just redundant. Go figure.
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