22 Dec
2007
22 Dec
'07
11:04 a.m.
On Sat, 22 Dec 2007, Tom Peters wrote:
Peter Wallace
Mesa Electronics
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Date: Sat, 22 Dec 2007 11:42:13 -0600
From: Tom Peters <tpeters at mixcom.com>
Reply-To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at
classiccmp.org>
Subject: Re: OT sockets for Nixies
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?
You need the series resistor because of the negative resistance of the glow
discharge.
Many years ago I made a clock with a National MM5316 clock chip and 4 of those
Burroughs Nixies (connected as 7 segmant). I used a PNP transistor to switch
the anode voltage with variable pulse width determined by a CDS light sensor
so the Nixie brighness adjusted automatically to room light. The Nixies
eventually wore out (in about 25 years...)
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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