[talk.bizarre] "Magic Eye" tubes - the Nixie Clock

brian@sdcsvax.UCSD.EDU (Brian Kantor) (07/15/87)

In Electronics World Magazine in the middle 60's there was a circuit for
a quartz crystal clock with Nixie display.  As I recall, you could build
it either with 12AU7 twin triodes, or 6SN7s, depending on whether you
had more octal or 9-pin tube sockets sitting in your junk box.

I got it about half built and couldn't afford the timebase crystal.
Sigh.

There were a number of ICs on the market in the early 70s that were
Nixie tube drivers - you could use ICs to divide down the timebase and
count the minutes, but LED displays were too expensive, so you'd go to
Nixies for output.  Nowadays, if I had to use Nixies, I'd use some cheap
horizontal output transistors and a BCD-to-10-line decoder.  I seem to
remember that you had to switch about 5 ma at 250v or so.

Ah, the old days of firebottle technology.  (Vacuum-packed depletion
mode electron-emission devices with built-in indicator lamp and
environmental heater.)
	- Brian

I am NOT an old fart.

hoffman@pitt.UUCP (Bob Hoffman) (07/15/87)

In article <3452@sdcsvax.UCSD.EDU> brian@sdcsvax.UCSD.EDU (Brian Kantor) writes:
>   Nowadays, if I had to use Nixies, I'd use some cheap
>horizontal output transistors and a BCD-to-10-line decoder.  I seem to
>remember that you had to switch about 5 ma at 250v or so.

That's about right.  It depends on the size of the Nixie tube being
used.  I built a clock some years ago that used some old B7971 Nixies
that are 2-1/2 inch high 15-segment alphanumeric displays.  They take
a little more current than the little ones.  I have them wired up like
7-segment displays and run them off an MM5314 clock chip with discrete
transistor drivers.

>Ah, the old days of firebottle technology.  (Vacuum-packed depletion
>mode electron-emission devices with built-in indicator lamp and
>environmental heater.)
>	- Brian

That's pretty good -- I like to think of them as Hot-Cathode FETs.

>I am NOT an old fart.

Me neither!  :-)

-- 
Bob Hoffman, N3CVL       {allegra, bellcore, cadre, idis, psuvax1}!pitt!hoffman
Pitt Computer Science    hoffman%pitt@relay.cs.net

cgs@umd5.umd.edu (Chris Sylvain) (07/18/87)

In article <3452@sdcsvax.UCSD.EDU> brian@sdcsvax.UCSD.EDU (Brian Kantor) writes:
<
<In Electronics World Magazine in the middle 60's there was a circuit for
<a quartz crystal clock with Nixie display.
< ... Nowadays, if I had to use Nixies, I'd use some cheap
<horizontal output transistors and a BCD-to-10-line decoder.

How about the Signetics DM8880, "High Voltage 7-Segment Decoder/Driver" ?
It can drive a Sperry SP-730 or SP-760 display tube directly, with TTL BCD
input..

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