22 Dec
2007
22 Dec
'07
9:42 a.m.
At 04:33 AM 12/22/2007 -0800, you wrote:
To actually drive the tubes. you need something that
can handle the volage/current. Use MPSA42 transistors
- they're cheap, about 8 cents each. One transistor
per cathode. Tie the anode of the tube to the power
source of 200v or whatever. Connect each cathode to
the collector of a MPSA42, tie the emitters all to
ground. To drive a segment, drive the base high
through a 33k resistor.
Great information, thanks. Someone else suggested MPSA42's and '92's as
well. The Burroughs spec sheets talk about the series anode R recommended
for each of three types of tubes; for the B-7971 they say 1.8k. Does your
suggestion eliminate the need for a anode resistor?
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. -Ian
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