[sci.electronics] "Magic Eye" tubes

john@frog.UUCP (John Woods, Software) (07/11/87)

Does anyone (a) know where I can get a Magic Eye tube (if they are even still
made), and (b) have information on how to use them (required voltages, etc.)?

Believe it or not, I want to use this "stab from the past" to indicate
CPU usage on a computer -- I specifically wanted something disturbingly
anachronistic (a meter came in second place...).

"Boss, I even put Murine in the magic eye!"
			-Rochester, on a Jack Benny show I heard recently


--
John Woods, Charles River Data Systems, Framingham MA, (617) 626-1101
...!decvax!frog!john, ...!mit-eddie!jfw, jfw%mit-ccc@MIT-XX.ARPA

Doktor of the Forbidden Sciences

rees@apollo.uucp (Jim Rees) (07/11/87)

I don't know if magic eye tubes are still made new, but you can usually
find them at ham radio flea markets.  These are a good source for anything
exotic or old.  Since you're in Framingham, I recommend the Heavy Hitter's
Hamfest at the Topsfield fair grounds July 24-26.

You'll need the usual tube voltages.  As I recall, they are triodes, with
the plate current (controlled by the grid voltage) controlling the amount
of "wink" (or whatever you call it).  I've got some schematics at home
and can probably get pin-outs and voltages if you can't figure it out.

larry@kitty.UUCP (Larry Lippman) (07/11/87)

In article <1495@frog.UUCP>, john@frog.UUCP (John Woods, Software) writes:
> Does anyone (a) know where I can get a Magic Eye tube (if they are even still
> made), and (b) have information on how to use them (required voltages, etc.)?
> 
> Believe it or not, I want to use this "stab from the past" to indicate
> CPU usage on a computer -- I specifically wanted something disturbingly
> anachronistic (a meter came in second place...).

	Yup, those tubes sure are an anachronism!  Some people I knew called
them "Cat's Eye" tubes.
	What you want is a type 6E5 manufactured by RCA.  Newark Electronics
(Chicago, IL) still has 'em in their catalog for $ 27.50.  You can probably
find them for less money in surplus stores or some mail-order companies
which specialize in the sale of vacuum tubes.
	There is also a 6U5, which is similar to the 6E5.  About 10 years
ago, an industrial electronics distributor that I deal with was doing some
housecleaning of ancient inventory and gave me a 6E5 along with a mounting
assembly made by Amphenol which was specifically used for panel mounting
(it has a nice Art Deco escutcheon plate :-) ).  I took the 6E5 and mounted
it in a small box as a conversation piece.  I built a DC-DC converter using
a Triad toroidal transformer to provide 250 volts DC @ 0.025 amperes from a
12 volt plug-type power supply.  I used a function generator IC with an op
amp to give me a triangular wave with an amplitude of 8 volts - necessary for
"full scale" deflection.
	The completed device "winks" when turned on, and has adjustable
wink "rate" and "depth" controls.  Talk about an anachronism of components
in that box!
	You will need 200 to 250 volts DC at 0.025 ampere maximum, 6 volts
AC or DC @ 0.3 ampere for filament, and your "deflection voltage" will range
from 0 to -8 volts for 0 to 90 degress deflection.

	I highly recommend this tube as an exercise in anachronism!

<>  Larry Lippman @ Recognition Research Corp., Clarence, New York
<>  UUCP:  {allegra|ames|boulder|decvax|rocksanne|watmath}!sunybcs!kitty!larry
<>  VOICE: 716/688-1231        {hplabs|ihnp4|mtune|seismo|utzoo}!/
<>  FAX:   716/741-9635 {G1,G2,G3 modes}    "Have you hugged your cat today?" 

faunt@spar.SPAR.SLB.COM (Doug Faunt) (07/12/87)

A mail order source is Fair Radio Sales, 1016 E. Eureka, PO Box 1105,
Lima Ohio 45802-1105, +1-419-227-6573.

They list "used-checked" types 6U5, 6E5, and 6AL7 for $7.00 each.
The 1629 is also an "eye" tube which they list for $2.50 used.

I like the idea, BTW.

phd@speech1.cs.cmu.edu (Paul Dietz) (07/13/87)

What exactly is a "Magic Eye" tube? (I think I'm showing my age, or lack
thereof...)
---
Paul H. Dietz
Carnegie Mellon University
---
Overheard the other day: "I'm so old, I even remember when calculator
displays were LED!"

davef@brspyr1.BRS.Com (Dave Fiske) (07/13/87)

In article <1004@speech1.cs.cmu.edu>, phd@speech1.cs.cmu.edu (Paul Dietz) writes:
> What exactly is a "Magic Eye" tube? (I think I'm showing my age, or lack
> thereof...)

> Overheard the other day: "I'm so old, I even remember when calculator
> displays were LED!"

Gee, I guess I'm an old fossil.
But I even remember:

Nixie tubes.


Well, what do you expect.  I also have an automatic phone dialer that I
bought from some mail-order company around 1976.  It doesn't take
advantage of DTMF (tone) dialing, but has a big sheet of plastic inside
that is rotated by an electric motor.  You "program" the numbers by
using an "IBM pencil" to fill in the appropriate digits (a la
standardized tests).  As the sheet rotates the graphite-filled spots
pass through a set of contacts, which send the appropriate number of
pulses.  The whole thing is pretty big, and has to sit underneath a
telephone.

Plus, it came with its own "Amphenol connector".
-- 
#     Well the Yanks hate the Reds and the Greeks hate the Turks             #  #     I really hate to say it but they're all a bunch of jerks               #
#     Seems like everybody's shakin'  'cause the big one's 'bout to fall     #  #     I'm just tryin' to hold it steady while I Piss On The Wall.            #
#                                                    J. Geils Band           #
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dsi@unccvax.UUCP (DataSpan R+D) (07/13/87)

In article <1495@frog.UUCP>, john@frog.UUCP (John Woods, Software) writes:
> Does anyone (a) know where I can get a Magic Eye tube (if they are even still
> made), and (b) have information on how to use them (required voltages, etc.)?
> 
> Believe it or not, I want to use this "stab from the past" to indicate
> CPU usage on a computer -- I specifically wanted something disturbingly
> anachronistic (a meter came in second place...).
> 

     Ahhhh yes, the dreaded Magic Eye tube. My favourite is the 6E5. You
might be able to get this from Richardson Electronics in Chicago, IL;
who stocks all kinds of weird receiving and transmitting tubes in depth.

     The 6E5 uses a 6-contact socket in the same pin circle radius as
tubes like the 807.  Finding a socket for this tube will probably prove
to be very difficult.

     Pins 1 and 6 (the big pins) connect to a 6.3 v heater. Pin 2 
connects to 125 - 250 vdc through a (nominally) 1.0 megohm resistor.
This is the series "triode-plate" connection. Pin 3 is connected
through a 1.0 megohm resistor to the controlling voltage. Bypass pin
3 to ground through a suitable capacitor (0.1 mFd at 50 volts should
do fine).  Pin 4 is the accelerator plate, which connects to (directly)
the 125-250 volt supply mentioned briefly above. Pin 5 is the cathode,
which should be tied through a 68 ohm resistor (or so) to ground.

     A voltage on the control grid resistor (to pin 3) of 0.0 volts
makes the "eye" appear "open", while a negative voltage of about 7
volts should just close the eye. The display appears at the end of
the envelope.

     The maximum plate current should be about 200 microamperes, while
the accelerator current is about 3500 microamperes. Your mileage will
vary.

     There is another type of "magic eye
tube, the 6AF6GT, which has two shadows which (I think) move independently
in a linear direction. The shadows are deposited on the side of the 
envelope. This tube is much less common than the first type.

David Anthony
DataSpan, Inc

ken@rochester.arpa (Ken Yap) (07/14/87)

Also if you are lucky you might be able to salvage one from an old radio.

	Ken

kchen@imagen.UUCP (Kok Chen) (07/14/87)

in article <1004@speech1.cs.cmu.edu>, phd@speech1.cs.cmu.edu (Paul Dietz) says:
> 
> What exactly is a "Magic Eye" tube? (I think I'm showing my age, or lack
> thereof...)
> Overheard the other day: "I'm so old, I even remember when calculator
> displays were LED!"                                        ^^^^^^^^^^
  ^^^^^^^^

OK, who remembers Nixie tubes?  (Any old fogies from Wang and Burroughs
still alive? :-) :-)

By the way, for Magic Eyes, you may be able to find Mullard and Philips
EM80 valves (used in wireless hacking in the early 1960's!  A poor high
schooler's S-meter.)

Also, you may be able to get the Magic eye tube that was used in the 
Dyna (Dynaco) FM-3 tuner from Stereo Cost Cutters in Ohio. (They advertise
in low-end "hi-"fidelity magazines.)  Unlike the better classical Cats-eyes, 
where you look into the *end* of the valve cylinder and see two rays (with
different sensitivities, so that one ray would close before the other, with
greater applied grid bias), the one on the Dyna tuner has it's florescent
target on the *side* of the valve.  Instead of the dark ray(s), you have a 
single dark band that opens and closes.


Kok S. Chen			..!decwrl!imagen!kchen
Imagen Corporation

ken@rochester.arpa (Ken Yap) (07/14/87)

Old tech hasn't quite died. Nixies "reappeared" as plasma displays and
the fluorescent displays use the same principle as the magic eyes albeit
at lower voltage.

	Ken

larry@kitty.UUCP (Larry Lippman) (07/14/87)

In article <1384@brspyr1.BRS.Com>, davef@brspyr1.BRS.Com (Dave Fiske) writes:
> > Overheard the other day: "I'm so old, I even remember when calculator
> > displays were LED!"
> 
> Gee, I guess I'm an old fossil.
> But I even remember:
> 
> Nixie tubes.

	Hell, Nixie tubes are MODERN compared to some of the stuff I worked
with in the 60's:

1.	Counter decades made of ten discrete labeled lamps, stacked on top
	of each other.  Example: Beckman Eput (tm) "meters" (really an
	early digital frequency counter using vacuum tube flip-flops).

2.	The "Decatron" tube, which consisted of a round tube with ten
	anodes, equally spaced about a circle.  It was nothing more than
	a multiple neon lamp, since it displayed no digits, but each anode
	was labeled on the panel.  Example: a Baird-Atomic nuclear scaler
	that I once used.

3.	Digital displays made from ten lucite plates, each with a number
	engraved, mounted one in front of each other, with each being
	lit by a miniature lamp whose light was "piped" by the lucite to
	the engraved area.  Example: Cubic Corp. "electromechanical"
	digital voltmeters (they used stepping switches in a null-balance
	arrangement).

4.	The "Nimo tube" tube, which was a miniature one inch diameter
	CRT which used electrostatic deflection and an aperture grid to
	select an electron mask which shaped an electron beam which
	struck a phosphor on the fron of the tube (it only displayed one
	character at a time).  What an ugly looking display this was!
	It could handle up to 64 characters, however.  It was manufacured
	by IEE, Inc.

	Nixie tubes are state-of-the-art compared to the above!  Actually,
we still have a fair amount of equipment in our labs which use Nixie tubes.
It was only in the later 70's that LED displays were bright enough to
compete with Nixie tubes (from the standpoint of visibility).

<>  Larry Lippman @ Recognition Research Corp., Clarence, New York
<>  UUCP:  {allegra|ames|boulder|decvax|rocksanne|watmath}!sunybcs!kitty!larry
<>  VOICE: 716/688-1231        {hplabs|ihnp4|mtune|seismo|utzoo}!/
<>  FAX:   716/741-9635 {G1,G2,G3 modes}    "Have you hugged your cat todayrnew

eap@bucsb.bu.edu.UUCP (Eric Pearce) (07/14/87)

In article <1841@kitty.UUCP> larry@kitty.UUCP (Larry Lippman) writes:
>In article <1384@brspyr1.BRS.Com>, davef@brspyr1.BRS.Com (Dave Fiske) writes:
>> > Overheard the other day: "I'm so old, I even remember when calculator
>> > displays were LED!"
>> 
>> Nixie tubes.
>
>	Hell, Nixie tubes are MODERN compared to some of the stuff I worked
>with in the 60's:
>
>	Nixie tubes are state-of-the-art compared to the above!  Actually,
>we still have a fair amount of equipment in our labs which use Nixie tubes.
>It was only in the later 70's that LED displays were bright enough to
>compete with Nixie tubes (from the standpoint of visibility).
>

Does anybody remember the nixie-tube clock in "Dressed to Kill" ?  They
showed it in the scene when Angie was at the museum guy's apartment, when
she wakes up in  the morning.  It was inside a clear plastic box - so you
could see all the electronics inside.  I always wanted to buy or build one...
Anybody know of a clock circuit for that type of tube ?  Or possibly a source
for one similar to the one in the movie ? 

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mcelfres@bnrmtv.UUCP (Forrest Mcelfresh) (07/14/87)

In article <1495@frog.UUCP>, john@frog.UUCP (John Woods, Software) writes:
> Does anyone (a) know where I can get a Magic Eye tube (if they are even still
> made), and (b) have information on how to use them (required voltages, etc.)?
> 

If you can't find one locally, let me know and I'll unearth my boxes
of tubes from out in the garage.   I may have one (no promises).
				     ^^^
6E5 "electron-ray tube": 6.3v ac/dc heater, 250v max plate & target,
grid voltage -8.0 for 0 degree shadow angle, 0 v for 90 degrees.

-- 
  |  All right, I will       |
  |  do my best to confine   |  (hplabs,amdahl,3comvax)!bnrmtv!mcelfres
  |  my .signature file      |
  |  to four lines, but it   |      Forrest McElfresh, W6BSC

rmarks@bbking.PRC.Unisys.COM (richard marks) (07/14/87)

Yes, you are showing your age.  If you were a radio ham and had a goonie box
you would know what a magic eye tube was.

It is a special type of vacume tube that was looked at from the top.  It was 
about 1 1/4" in diameter and mostly glowed green.  The green was about the 
shade of our PC monochrome monitiors.  A pie shaped section of less than 90
degrees was not illuminated.  As the voltage changed, the angle of the pie
shaped section also changed.  They were usually used as a signal strength
indicator.  The smaller the angle, the stronger the signal.
Richard Marks K2LOU

ken@rochester.arpa (Ken Yap) (07/14/87)

|2.	The "Decatron" tube, which consisted of a round tube with ten
|	anodes, equally spaced about a circle.  It was nothing more than
|	a multiple neon lamp, since it displayed no digits, but each anode
|	was labeled on the panel.  Example: a Baird-Atomic nuclear scaler
|	that I once used.

Actually it was a little more than a multiple neon lamp because it had
auxiliary electrodes which could cause the glow to migrate to the next
anode. By applying the appropriate sequence of pulse waveforms you could
get it to count. Hence its use as a high speed counter before RTL, DTL
and TTL counters like 7490 came along.

	Ken

paul@dual.UUCP (Baker) (07/15/87)

< The "Decatron" tube, which consisted of a round tube with ten
< anodes, equally spaced about a circle.  It was nothing more than
< a multiple neon lamp, since it displayed no digits, but each anode
< was labeled on the panel.  Example: a Baird-Atomic nuclear scaler
< that I once used.

Actually the Decatron was quite ingenious.  It not only indicated, but
also did the counting.  A major plus in pre-IC days.  They were not
particularly fast, I seem to recall a figure of a few hundred KHz.
They consumed little power, just a few mA at hundreds of volts.

There was a whole range of rather odd neon type devices available at one
time, that could be used for counting and other logic.  These typically
had a trigger electrode that "fired" the device and started conduction
between the main electrodes.  Reducing the current through the main path
would turn the device off again.  There must be some people on the net
who actually designed with these things.

Paul Wilcox-Baker
Tel 415 549 3854
Telex ITT 470844
Dual Systems Corp
2530 San Pablo Ave
Berkeley CA 94702

larry@kitty.UUCP (Larry Lippman) (07/16/87)

In article <10018@dual.UUCP>, paul@dual.UUCP (Baker) writes:
> There was a whole range of rather odd neon type devices available at one
> time, that could be used for counting and other logic.  These typically
> had a trigger electrode that "fired" the device and started conduction
> between the main electrodes.  Reducing the current through the main path
> would turn the device off again.  There must be some people on the net
> who actually designed with these things.

	Western Electric was well known for using cold cathode tubes in
telephone switching ciruits during the 40's, 50's and early 60's.  These
were essentially three element tubes having a cathode, an anode, and a
"starter anode".  The anode -> cathode voltage was usually + 130 volts,
and the tube would conduct sufficient current to operate a relay.  Only
a small about of current was applied to the "starter anode" to cause the
tube to go into conduction mode.
	Compared to the "non-WECO" world, these cold cathode tubes (like
the WECO 346C) were of bizarre design.  For example, in addition to being
filled with an inert gas these tubes contained a radioactive material
to facilitate ionization.  The earlier tubes contained radium bromide,
with later tubes containing krypton-85.
	A common example of using these tubes was for timing circuits
in the middle of relay-logic switching apparatus.
	In the mid 1950's, these cold cathode tubes reached their
zenith when WECO designed a prototype "electronic" (I used the term
loosly) telephone switching system which used cold cathode tubes as
the switching matrix.  This ESS :-) machine was fully described in the
"Bell System Technical Journal".  Contained in the article were
photographs, including one of the weirdest looking telephone set I
have ever seen!  The telephone set resembled a checkwriter with a
handset.  I don't recall the exact BSTJ issue, but anyone interested
in history or electronic trivia should check it out.

<>  Larry Lippman @ Recognition Research Corp., Clarence, New York
<>  UUCP:  {allegra|ames|boulder|decvax|rocksanne|watmath}!sunybcs!kitty!larry
<>  VOICE: 716/688-1231        {hplabs|ihnp4|mtune|seismo|utzoo}!/
<>  FAX:   716/741-9635 {G1,G2,G3 modes}    "Have you hugged your cat today?" 

larry@kitty.vanP (Larry Lippman) (07/16/87)

In article <10018@dual.UUCP>, paul@dual.UUCP (Baker) writes:
> There was a whole range of rather odd neon type devices available at one
> time, that could be used for counting and other logic.  These typically
> had a trigger electrode that "fired" the device and started conduction
> between the main electrodes.  Reducing the current through the main path
> would turn the device off again.  There must be some people on the net
> who actually designed with these things.

	Western Electric was well known for using cold cathode tubes in
telephone switching ciruits during the 40's, 50's and early 60's.  These
were essentially three element tubes having a cathode, an anode, and a
"starter anode".  The anode -> cathode voltage was usually + 130 volts,
and the tube would conduct sufficient current to operate a relay.  Only
a small about of current was applied to the "starter anode" to cause the
tube to go into conduction mode.
	Compared to the "non-WECO" world, these cold cathode tubes (like
the WECO 346C) were of bizarre design.  For example, in addition to being
filled with an inert gas these tubes contained a radioactive material
to facilitate ionization.  The earlier tubes contained radium bromide,
with later tubes containing krypton-85.
	A common example of using these tubes was for timing circuits
in the middle of relay-logic switching apparatus.
	In the mid 1950's, these cold cathode tubes reached their
zenith when WECO designed a prototype "electronic" (I used the term
loosly) telephone switching system which used cold cathode tubes as
the switching matrix.  This ESS :-) machine was fully described in the
"Bell System Technical Journal".  Contained in the article were
photographs, including one of the weirdest looking telephone set I
have ever seen!  The telephone set resembled a checkwriter with a
handset.  I don't recall the exact BSTJ issue, but anyone interested
in history or electronic trivia should check it out.

<>  Larry Lippman @ Recognition Research Corp., Clarence, New York
<>  vanP:  {allegra|ames|boulder|decvax|rocksanne|watmath}!sunybcs!kitty!larry
<>  VOICE: 716/688-1231        {hplabs|ihnp4|mtune|seismo|utzoo}!/
<>  FAX:   716/741-9635 {G1,G2,G3 modes}    "Have you hugged your cat today?" 

bobmon@iucs.UUCP (Che' Flamingo) (07/16/87)

Snivel.  Whimper.  I grovel.  I plead.  I lick honey off the starlet of your
choice . . . .

		WHAT ARE MAGIC EYE TUBES ???

I know about Nixie tubes.  I know about LEDs.  I know about antediluvian digital
watch displays.  I even know about rotating shafts with little cards that have
digits painted on them, which flop past a little finger and into an incandescent
lamp.  But Magic Eye Tubes have got me down.  So What Are They, Already?????????

ken@rochester.arpa (Ken Yap) (07/16/87)

This variety may not have existed in this country but there was another
kind which varied a fluorescent strip. At maximum grid voltage the two
strips closed, like a curtain. Same principle.  Good fun. Imagine: I
wanted to make a bike speedometer with those things years ago. With a
voltage inverter and all. I was a bit crazy then. No jokes about my
still being crazy, thanks. :-)

	Ken

larry@kitty.UUCP (Larry Lippman) (07/16/87)

In article <584@sol.ARPA>, ken@rochester.arpa (Ken Yap) writes:
> This variety may not have existed in this country but there was another
> kind which varied a fluorescent strip. At maximum grid voltage the two
> strips closed, like a curtain. Same principle.  Good fun. Imagine: I
> wanted to make a bike speedometer with those things years ago. With a
> voltage inverter and all. I was a bit crazy then. No jokes about my
> still being crazy, thanks. :-)

	In keeping the magic eye tube technology, you should have used a
"vibrator" (the _electronic_ kind :-) ) as the inverter element.  Even
better, you should have used a synchronous vibrator which also functioned
as a rectifier - it had auxiliary pole-changing contacts.
	Does anyone remember the pleasant, "state-of-the-art" hum which
emanated from portable equipment which used vibrators?  I seem to recall
that most vibrators operated around 115 Hz.
	Hmmm... Have I just severely dated myself talking about vibrators?

<>  Larry Lippman @ Recognition Research Corp., Clarence, New York
<>  UUCP:  {allegra|ames|boulder|decvax|rocksanne|watmath}!sunybcs!kitty!larry
<>  VOICE: 716/688-1231        {hplabs|ihnp4|mtune|seismo|utzoo}!/
<>  FAX:   716/741-9635 {G1,G2,G3 modes}    "Have you hugged your cat today?" 

jans@tekchips.TEK.COM (Jan Steinman) (07/17/87)

<<<...you should have used a "vibrator" (the _electronic_ kind :-) ) as the 
inverter element...  Does anyone remember the pleasant, "state-of-the-art" hum 
which emanated from portable equipment which used vibrators?  I seem to recall 
that most vibrators operated around 115 Hz.  Hmmm... Have I just severely dated 
myself talking about vibrators?>>>

I remember as a 9th-grader, ripping apart car radios.  At the time, my dad had 
just replaced the ignition coil on our Ford.  Well, I mounted the vibrator, 
ignition coil, and two lantern batteries on a small chassis, wired the whole 
thing to the striker-plate of the science classroom door, and closed it behind 
me.  No one could get in for about 30 minutes until the batteries died.  For 
some reason, I didn't get expelled that time!

:::::: Software Productivity Technologies    ---    Smalltalk   Project ::::::
:::::: Jan Steinman N7JDB	Box 500, MS 50-470	(w)503/627-5881 ::::::
:::::: jans@tekcrl.TEK.COM	Beaverton, OR 97077	(h)503/657-7703 ::::::

root@conexch.UUCP (Super user) (07/17/87)

In article <1495@frog.UUCP>, john@frog.UUCP (John Woods, Software) writes:
> Does anyone (a) know where I can get a Magic Eye tube (if they are even still


Believe it or not, all early radio equipment is still available from 
users collections.  This includes some of the first electronic apparati
ever to appear on the face of this planet.  I suggest you contact
The AWA at:

	Bruce Kelley
	Antique Wireless Association
	East Blumfield, NY
	(716) 657-7489
	(716) 657-6260

or:

	Bruce Kelly
	Main Street
	Holcomb, NY 14469

They should be able to direct you to a source near you.
 
Best Regards,
Larry Dighera

-- 
Larry Dighera: 
The Consultants' Exchange BBS: (714) 842-6348: IBM-PC BBS
                               (714) 842-5851: Xenix guest account
UUCP: ...!ucbvax!ucivax!mickey!conexch!sysop     Login: nuucp

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

In article <1838@kitty.UUCP> larry@kitty.UUCP (Larry Lippman) writes:
<
<	Yup, those tubes sure are an anachronism!  Some people I knew called
<them "Cat's Eye" tubes.
< ... What you want is a type 6E5 manufactured by RCA.
< ... There is also a 6U5, which is similar to the 6E5.

I'm partial to the 6CD7. It's "output" is two, light green semi-circles around
a dark "pupil". The semi-circles can be coerced to overlap 10 or 20 degrees or
leave open space at the ends of about 50 degrees. Shortwave receivers used them
as AM tuning indicators. Much nicer than the "linear" indicators in my opinion.

-- 
--==---==---==--
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   UUCP: ..!seismo!umd5.umd.edu!cgs

miket@brspyr1.BRS.Com (Mike Trout) (07/21/87)

I'm not sure if this is exactly a "Magic Eye" tube, but it sounds similar.

A friend of mine in high school had a beat-up old Rambler (or possibly Nash; I
don't remember the year but I'd guess about mid to late 50s).  The center
console had a large circular "tube" item around which were arrayed some archaic
controls.  Underneath it all was the legend "Weather Eye".  When I first saw
this I (being a naive teenager) asked, "whutinhell izzat?  Sum kinda tornado
warning device?" (This was in Jokelahoma.)

Actually, the console was the heater/defroster control unit.  The tube in the
middle showed perhaps fan speed (I'm not sure about this; maybe it could have
been some kind of thermostat indicator?).  The whole gizmo was real sci-fi
looking and could have come out of the control panel for Fireball XL-5.  Am I
nuts, or is this something like a "Magic Eye"?  Does anybody remember this car?

Incidentally, this car also had:
1.  one of those really neato push-button automatic transmissions
2.  a push-button starter that had to be activated AFTER you turned the key
3.  a rectangular steering wheel
4.  under the back seat, there was...uh, never mind


 
-- 
Michael Trout (miket@brspyr1) =-=-=-=-=-=-= UUCP:ihnp4!dartvax!brspyr1!miket
BRS Information Technologies, 1200 Rt. 7, Latham, N.Y. 12110  (518) 783-1161
         .    . . .... .........:.::::.:::::::::.:::::::::::::::::::::::::::o
"By and large, I was only trying to fool Mr. Trout." -Dan Rather

rmrin@inuxh.UUCP (D Rickert) (07/23/87)

> < The "Decatron" tube, which consisted of a round tube with ten
> < anodes, equally spaced about a circle.  It was nothing more than
> < a multiple neon lamp, since it displayed no digits, but each anode
> < was labeled on the panel.  Example: a Baird-Atomic nuclear scaler
> < that I once used.
> 
> Actually the Decatron was quite ingenious.  It not only indicated, but
> also did the counting.  A major plus in pre-IC days.  They were not
> particularly fast, I seem to recall a figure of a few hundred KHz.
> They consumed little power, just a few mA at hundreds of volts.
> 
> There was a whole range of rather odd neon type devices available at one
> time, that could be used for counting and other logic.  These typically
> had a trigger electrode that "fired" the device and started conduction
> between the main electrodes.  Reducing the current through the main path
> would turn the device off again.  There must be some people on the net
> who actually designed with these things.
> 
> Paul Wilcox-Baker
> Tel 415 549 3854
> Telex ITT 470844
> Dual Systems Corp
> 2530 San Pablo Ave
> Berkeley CA 94702

Yup, many years ago I did a lab project in which we used a Decatron
for motor speed control!  The idea was for the circuit to keep the
same little dot continuously lit if the motor speed stayed constant
at the set point.  A wonderful mix of analog, digital, and power
technology.  I think we may have even had a mag amp somewhere in
the circuit (you know, solid state Neanderthal style).

larry@kitty.UUCP (Larry Lippman) (07/24/87)

In article <591@inuxh.UUCP>, rmrin@inuxh.UUCP (D Rickert) writes:
> Yup, many years ago I did a lab project in which we used a Decatron
> for motor speed control!  The idea was for the circuit to keep the
> same little dot continuously lit if the motor speed stayed constant
> at the set point.  A wonderful mix of analog, digital, and power
> technology.  I think we may have even had a mag amp somewhere in
> the circuit (you know, solid state Neanderthal style).

	Magnetic amplifiers!  I haven't run across those gadgets for servo
control in years.  They came in half-wave, full-wave and push-pull
configurations, and were particularly handy for military applications
which involved controlling 115 volt 3-phase 400 Hz motors.
	There is something used for motor control which is even older
than magnetic amplifiers -  the amplidyne.  This gadget was a close-coupled
[AC or DC] motor driving an AC generator (often 3-phase) with a DC field
coil.  Varying the voltage/polarity of the DC field controlled the resultant
AC voltage and phase relationship.  The amplidyne generator output then
drove a servo motor (usually 3-phase).  The amplidyne was popular during
World War II for controlling search radar antennas (PPI display).  Amplidynes
were well-described in the MIT "Rad Lab" series - which was still required
reading when I got my EE during the 60's.

<>  Larry Lippman @ Recognition Research Corp., Clarence, New York
<>  UUCP:  {allegra|ames|boulder|decvax|rocksanne|watmath}!sunybcs!kitty!larry
<>  VOICE: 716/688-1231        {hplabs|ihnp4|mtune|seismo|utzoo}!/
<>  FAX:   716/741-9635 {G1,G2,G3 modes}    "Have you hugged your cat today?" 

jeffw@midas.TEK.COM (Jeff Winslow) (07/24/87)

In article <1871@kitty.UUCP> larry@kitty.UUCP (Larry Lippman) writes:
>In article <591@inuxh.UUCP>, rmrin@inuxh.UUCP (D Rickert) writes:
>>              I think we may have even had a mag amp somewhere in
>> the circuit (you know, solid state Neanderthal style).
>
>	Magnetic amplifiers!  I haven't run across those gadgets for servo
>control in years...

Hey, don't laugh. Magamps are still commonly used in switching power supplies,
especially multi-output switchers, for regulation of outputs with currents
too high to be efficiently regulated with a series-pass regulator. Of course,
they tend to be a bit smaller than those Neanderthals of yore - we're talking
40kHz and up, here.

						Jeff Winslow

PS. Sci.electronics folk, please edit the #$*&^#@ newsgroup line so these
things don't go over to talk.bizarre!! They seem to be ignoring us so far,
but take it from me, they can get really nasty! I know, I'm one of them.