OT sockets for Nixies
mcguire at neurotica.com
Fri Dec 21 21:53:04 CST 2007
On Dec 21, 2007, at 8:58 PM, Tom Peters wrote:
> This is off-topic in terms of the industry involved, but not too
> far off in the time period this stuff dates from.
> I've got some very nice, rather large Burroughs nixies- 7971 types.
> They're 4.8" high, "British flag" display which looks to be 2.5"
> high inside the glass. They have 15 segments each-- 14 in the
> alphanumeric display part of the tube and one sort-of cursor, an
> underline character with the ends bent downwards.
> I hear one can dismember D-shell connectors to get some sockets to
> solder to a pc board to connect to these. But my problem is driving
> Anyone know a good way to drive these, four or six of them in an
> array? I need 170 volts, 21ma all cathodes, between 4.0 and 6.0ma
> any individual cathode. I was thinking of a pic at each tube, sort-
> of a character generator that would take an ascii code and drive
> the right segments. Some sort of escape code would let you send 16
> bits to be interpreted literally, i.e. turn on the literal segments
> corresponding to the bits set, for more fanciful displays.
B7971 tubes are very nice indeed. A PIC with lookup tables in
code memory is a reasonable approach.
You can gate the 170VDC to the cathodes with MPSA42 transistors
(NPN, Vceo=300V). If you'll be multiplexing, you can drive the
anodes with MPSA92s (PNP, Vceo=300V, effectively the PNP version of
the MPSA42). Both are available new in lots on eBay for next to
I generate the 170VDC for Nixie (and similar) applications from
12VDC using an MC34063-based step-up switching regulator, the design
of which is based on a circuit from one of the chip's app notes. I
can send you the schematic if that'd be helpful.
Port Charlotte, FL
Farewell Ophelia, 9/22/1991 - 7/25/2007
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