| Burroughs HB-105 Pixie Tube | |
| Written by AnubisTTP on 2008-11-26 |
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The problem with Nixie tubes, both in the 1960s and now, is that they are simply far too expensive. Pixie tubes are a curious technological dead-end, an attempt by Burroughs to make a cheaper, more affordable gas discharge display. Instead of having a series of shaped cathodes for each digit, a Pixie tube has a single shaped anode with number shaped holes over each of the pins in the stamped glass base. Stub cathodes are attached to the top of each pin, which glow through the holes in the anode during operation to indicate a numeric value. Pixie tubes cost only about a quarter as much to manufacture as a Nixie tube of similar size. The low cost did not win over users however, a Pixie tube produces a remarkably tiny and unreadable display, and most early Nixie tubes were used in equipment costing many multiples of thousands of dollars where the expense of the display could be justified. Nobody knows what the first Pixie tube part number is, but given the HB105's Haydu part number and ridiculous oversized envelope, it is definitely an early example.
Ironically, Pixie tubes are now quite a bit more expensive than the Nixie tubes they were originally designed to undercut; they are quite popular among electronics hobbyists for making clocks and other novelty items. Burroughs originally marketed the tube's ability to be controlled by a five volt differential in an attempt to make the tubes seem more 'transistor friendly', but modern hobbyists typically drive them with standard Nixie circuits instead.
Burroughs HB-105 'Pixie' nixie style numeric indicator tube. The HB-105 is widely believed to be the first pixie tube part number.
The HB105 takes the phrase 'vacuum tube' to the limit, most of the tube's envelope is empty space.
Pixie tube family photo. From left to right,HB105, B9012, National 9012, ZM1050.
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