Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!seismo!gatech!bloom-beacon!husc6!mit-eddie!genrad!decvax!decwrl!pyramid!nsc!csi!epimass!oliveb!ames!sunybcs!kitty!larry From: larry@kitty.vanP (Larry Lippman) Newsgroups: sci.electronics Subject: Re: "Magic Eye" tubes Message-ID: <1844@kitty.vUCP> Date: Wed, 15-Jul-87 22:50:45 EDT Article-I.D.: kitty.1844 Posted: Wed Jul 15 22:50:45 1987 Date-Received: Sat, 18-Jul-87 08:14:42 EDT References: <1495@frog.UUCP> <35ffa63b.b8ab@apollo.uucp> <6@spar.SPAR.SLB.COM> <10018@dual.UUCP> Organization: Recognition Research Corp., Clarence, NY Lines: 36 Summary: Cold cathode tubes 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?"