Web: http://www.pearl-hifi.com 86008, 2106 33 Ave. SW, Calgary, AB; CAN T2T 1Z6 E-mail: [email protected] Ph: +.1.403.244.4434 Fx: +.1.403.245.4456 Inc. Perkins Electro-Acoustic Research Lab, Inc. ❦ Engineering and Intuition Serving the Soul of Music

Please note that the links in the PEARL logotype above are “live” and can be used to direct your web browser to our site or to open an e-mail message window addressed to ourselves. To view our item listings on eBay, click here. To see the feedback we have left for our customers, click here.

This document has been prepared as a public service . Any and all trademarks and logotypes used herein are the property of their owners. It is our intent to provide this document in accordance with the stipulations with respect to “fair use” as delineated in Copyrights - Chapter 1: Subject Matter and Scope of Copyright; Sec. 107. Limitations on exclusive rights: Fair Use. Public access to copy of this document is provided on the website of Cornell Law School at http://www4.law.cornell.edu/uscode/17/107.html and is here reproduced below:

Sec. 107. - Limitations on exclusive rights: Fair Use

Notwithstanding the provisions of sections 106 and 106A, the fair use of a copyrighted work, includ- ing such use by reproduction in copies or phono records or by any other means specified by that section, for purposes such as criticism, comment, news reporting, teaching (including multiple copies for class- room use), scholarship, or research, is not an infringement of copyright. In determining whether the use made of a work in any particular case is a fair use the factors to be considered shall include:

1 - the purpose and character of the use, including whether such use is of a commercial nature or is for nonprofit educational purposes;

2 - the nature of the copyrighted work;

3 - the amount and substantiality of the portion used in relation to the copy- righted work as a whole; and

4 - the effect of the use upon the potential market for or value of the copy- righted work.

The fact that a work is unpublished shall not itself bar a finding of fair use if such finding is made upon consideration of all the above factors

♦ PDF Cover Page ♦ ♦ Verso Filler Page ♦ RADIO SERVICE TECHNIQUES 3

This article by RCA is intended to assist servicemen in their understanding of transistor radio operation, and is written to cover the various types of fault which may be encountered. It is the third of a series of three articles being presented on transistorized radios.

CURRENT RANGE OF EEV TV CAMERA TUBES 11

Brief details are given of a range of eight image orthicons and two vidicons manufactured by the English Electirc Valve Co. Ltd.

RADIOTRON AV25 DEMONSTRATION 12

Data on a triode specially designed for class and lecture room demonstrations. This latest data supersedes previous data published in October, 1956.

HIGH FIDELITY USING RADIOTRON 6973 .... 15

This article describes two circuits using 6973's, one a moderate·cost 15 watt circuit, the other a low·cost 10 watt circuit. Characteristics. of the 6973 were published in "Radiotronics", January, 1958.

NEW RCA RELEASES 19

2N373 P·fII·P drift transistor, 455 Kc if stages. 2N374 P·N·P drift transistor, AM converter stages. 2N176 P·N·P transistor power amplifier, 2 w max. 21'1351 P·N·P transistor power amplifier, 4 w max. 2N376 P·N·P transistor, power amplifier, 4 w max. 1N1763 Diffused·;unction silicon . 1N17 64 Di#fused·;unction silicon rectifier.

Radiotronics is published twelve times a year by the Wireless Press for Amalgamated Wireless Valve Company Pty. Ltd The annual subscription rate in Australasia is 10/ -, in .S.A. and dollar countries $1.50, and in all other countries . U 12/6. Price of a single copy is 1/-. Subscribers should promptly notify Amalgamated Wireless Valve Company Pty. Ltd., Box 2516, G.P.O., Sydney, and also the local Post Office of any change of address, allowing one month for the change to become effective. Original articles in Radiotronics may be published without restrictions provided that due acknowledgement is given. Devices and arrangements shown or described herein m ay use patents of AWV, RCA or others. Information is furnished without responsibility by AWV or RCA for its use and without prejudice to AWV's or RCA's patent rights. Information published herein concerning new RCA releases is intended for information only, and present or future Australian availability is not implied. EDITOR .... BERNARD J. SIMPSON

PRINTED BY THE CLOISTER PRESS, 45-49 GEORGE STREET, REDFERN Radiotronics January, 1959 TRANSISTOR FUNDAMENTALS - PART 1 23 With this item we start a short course on transistor fundamentals and applica­ tions. See the announcement at the foot of the page.

NEW PUBLICATIONS 29 The following publications are reviewed this month: "Television Engineering", Vol. 4. "Reflex ". "Radiotron High Fidelity". "AWV ".

NEW RCA RELEASES 30 6JJ2 "Premium" sub-miniature high-mu twin triode. 6342-A Ten-stage multiplier . 7199 Medium-mu trio de - with sharp cutoff . 7262 One inch vidicon for transistorized cameras. 7264 Fourteen-stage multiplier phototube.

AMPLITUDE MODULATION TODAY 31

Subtitled 11A Review of Some Modern Amplitude-Modulation Systems", this article discusses methods of amplitude modulation which have come into wide use over the last decade, and explains terms like SSB and DSB which are scattered through today's radio literature.

DRIFT TRANSISTORS IN COMPUTERS 36 A note on the "Current Switching Model" system or using transistors in computer circuits, in which full advantage can be taken of the special properties of drift transistors.

INSULATED MOUNTING WASHERS FOR POWER TRANSISTORS 40 A method of mounting 2N301 and similar power transistors which provides electrical insulation of the collector from the chassis without appreciable reduc­ tion in heat-transfer efficiency.

By courtesy of RCA we are able to bring you a short course on transistor fundamentals and applications. This course was prepared by the joint efforts of the RCA Victor and Semiconductor Divisions, and is designed to give an engineer or technician with no previous semiconductor experience a quick apprecia­ tion of transistors without complex text book op arations. The course will consist of Transistor Fundamentals, in two parts, and Transistor Applications, also in two parts. These sections will be printed in successive issues of Radiotronics. In June we will present a set of review questions on the course, enabling readers to check themselves on the theory which has been presented during the previous four months.

Radiotrn:zics February, 1959 STEREO IN THE HOME 47 This is an article by an authority on the subject, Mr. H. F. Olson, of the ReA Princeton Laboratories. His article deals with the problems of creating realism in home reproduction, and the means available to achieve a performance reasonably comparable with the original performance.

SOME ASPECTS OF SYNCHRONIZATION IN TV RECEIVERS .. ... 52 Mr. J. van der Goot (AWV Application Laboratory) has covered in this impressive article a wide field. He deals first with vertical and horizontal oscillators, then afc systems, and concludes with a comprehensive discussion of the inversion, amplification, limiting and cli,ilping of t;re sync pulse.

TRANSISTOR FUNDAMENTALS - CHAPTER 2 58 This is the second and concluding chapter of our course on transistor fundamentals. As previously announced, this will be followed by a two-part article on Transistor Applications.

This month we are carrying on the work of bringing you interesting and "down-to-earth" articles in the field of electronics, in the enlarged 1959 volume of "Radiotronics". Among the articles now being p.epared is a series on audio amplifiers, ranging from an ultra-linear 30 watt high fidelity unit to a 400 watt unit with 2 % total ha,'monic distortion. We have been bringing you lots of information on transistors in recent issues, and will continue

to do so in the future. The reason is obvious - one in electronics can afford to be "out of the picture" where semiconductors are concerned. The110 rapid growth of these units, in scope, quantity and performance, means that an extensive coverage is needed to bring readers up to date, and keep them up te date on transistors. The advent of the transistor, in its many shapes and forms, has been likened to the discovery of the thermionic valve. Whilst this may not be strictly true, it does perhaps convey some idea of the magnitude the effect this device is having on the electronics industry. of

Radiotronics is published twelve times a year by the Wireless Press for Amalgamated Wireless Valve Company Pty.

Ltd. The annual subscription rate in Australasia is 10/ -, in .S.A. and dollar countries $1.50, and in all other countries 12/6. Price of a single copy is 1/-. U Subscribers should promptly notify Amalgamated Wireless Valve Company Pty. Ltd., Box 2516, G.P.O., Sydney, and also the local Post Office of any change of address, allowir:g one month for the change to become effective.

Original articles in Radiotronics may be published without restrictions provided that due acknowledgement is given. Devices and arrangements shown or described herein may use patents of A WV, RCA or others. Information is furnished without responsibility by A WV or ReA for its use and without prejudice to A WV's or RCA's patent rights. Information published herein concerning new RCA releases is intended for information only, and present or future Australian availability is not implied.

EDITOR BERNARD J. SIMPSON

PRINTED BY THE CLOISTER PRESS, 45_49 GEORGE STREET. REDFERN Radiotronic5 March, 1959. TRANSISTOR APPLICATIONS - CHAPTER ONE 71

Last month we concluded the discussion on transistor fundamentals, and we now commence a two-part article on their applications. SUbjects covered in this section are transistor amplifiers, methods of coupling, and gain controls.

SOME ASPECTS OF SYNCHRONIZATION IN TV RECEIVERS 79

Part two of this interesting and instructive article by J. van der Goot (AWV Application Laboratory) deals with horizontal oscillators and afc systems, and follows logically the discussion of vertical oscillators which was given in the first part last month.

STEREO IN THE HOME - CONCLUSION 88

The conclusion of this excellent article by Harry f. Olson complete.> the presenta­ tion of our first article on stereo. Mr. Olson, of the RCA Princeton Laboratories, is a world authority on acoustical enginering, amI his article carries the mark of that authority.

RADIOTRON 17BZP4 PICTURE TUBE 95

full technical data on the latest J 7" Jl0° deflection picture tube.

RADIOTRON 21 CEP4 PICTURE TUBE 98

The 2J" HO° picture tube is described, with full ted-mical data.

NEW PUBLICATIONS 101

Three new publications are reviewed this month: "Servicing Transistorized Radios" "" "Basic Electronics"

DESIGN-MAXIMUM SYSTEM FOR RATING VALVES 102

An introductory note on the design-maximum system is appropriate at this time and foreshadows its great use in the electron;';s industry consequent upon the advantages it offers over the two other systems. further information will be presented soon in these pages.

The swing over to the Design-Maximum System of rating valves announced by RCA and other manufacturers will take effect with new entertainment types issued. Later, ratings for the more popular entertainment types already published under the Design-Centre System will be reissued in the Design-Maximum System. The merits of the new system are described briefly in the note printed in this issue on page 102.

Radiotronics April, 1959 KT88 IN AUDIO AMPLIFIERS - PART 1. 107

In February last year we announced the KT88 beam power valve for af amplifiers, and published some circuits. Further data is now available, covering a range of amplifiers from 30 to 400 watts output.

THE DESIGN-MAXIMUM RATING SYSTEM ...... 115

This short article presents the basic concepts of the new Design.Maximum Rating System. As mentioned last month on this page, the new system will take effect with new entertainment-type valves as they are issued.

SOME ASPECTS OF SYNCHRONIZATION IN TV RECEIVERS 119

The concluding part of this interesting article deals with the processing of the sync pulse. The article ends with a circuit embodying the principles discussed in the article.

TRANSISTOR APPLICATIONS - CHAPTER TWO 125

Also concluding in this issue ;s the short course on transistor theory and appli­ cations. Next month we will present a short series of questions on the course, with the ob;ect of allowing readers to check themselves on the sub;ect matter.

INTEGRATED ELECTRONIC DEVICES 136

A new approach to micro-miniaturization is described in this short note by J. T. Wallmark, a research engineer in the ReA Princeton Laboratories.

For the second month in succession we are able to bring you an expanded issue of your magazine. Of particular interest is the short note on the miniaturization electronic equipment by Dr. J. T. Wallmark. This note points the way to the manufacture of equipment0 � of hitherto impossibly small size. It is anticipated that the principle of integrating many functions into single small component will enable engineers to reverse the tre nd of increasing apparatus !iize aoccasioned by its increasing complexity, and lead to the development of more economical, versatile and reliable equipment.

Radiotroni('s ]flay, 1%9 KT88 IN AUDIO AMPLIFIERS - PART 2 143 In this second and concluding part of the article dealing with the application of the KT88, we pass from the lower-powered amplifiers suitable for home use to three units suitable for high-quality public address work.

TRANSISTOR FUNDAMENTALS AND APPLICATIONS - REVIEW QUESTIONS 154

Last month's issue brought us to the end of the short four-part course on transistors. These articles have been enthusiastically received by our readers, and we know the keener types will en;oy testing their newly-gained knowledge of transistors by checking up with these questions.

TRANSISTOR GLOSSARY 158

Continuing our policy of keeping up with transistors for readers, we present OUt this month a glossary gleaned and compiled by our transistor experts. Its very surprising ;ust how much information can be condensed into a small space using this technique, and we hope you like it.

SILICON 1N1763, 1N1764 164

These units are diffused-;unction silicon rectifiers designed for use in the power supplies of entertainment-type equipment and other electronic apparatus. This data expands the announcement made in January last.

Radiotronics is published twelve times a year by Wireless Press for Amalgamated Wireless Valve Company Pty. Ltd. The annual SUbscription rate in Australasia the10 /-, in U.S.A. and dollar countries $1.50, and in all other countries 12/6. Price of a single copy is 1/-. is Subscribers should promptly notify Amalgamated Wireless Pty. . Box 2516, G.P.O., Sydney. and also the local Post Office of any change of address, allowingValve onc Company month for theLtd change . to become effective. Original articles in Radiotronics may be published without restrictions provided that due acknowledgement is given. Devices and arrangements shown or described herein use patents A ReA or others. Information is furnished without responsibility by A or RCA for maits y use and withoutof prejWV.udice to A WV's or RCA's patent rights. Information published herein concerningWV new RCA releases intended for information only, and present or future Australian availability is not implied. is

EDITOR BERNARD J. SIMPSON

Radiotronics June, 1959 SOUND REPRODUCING SYSTEMS - MONAURAL, BI NAURAL, MONOPHONIC, STEREOPHONIC 171 It is our pleasure to bring you yet another article by Mr. H. F. O/son, who ;s a world authority on acoustics and sound reproduction. In this timely article, Mr. O/son resolves very neatly the confusion of terms that has arisen around the different types of systems.

FEATURES OF FLUORESCENT SCREENS 174 A summary of the different phosphors used in cathode.ray tubes, and rhe applica­ tions for which they are intended.

THE WEEKEND SPECIAL 175 A constructional article for "Hams" who don't want to leave their hobby behind when they go on weekend or holiday trips, describing a portable 40-metre cw station built into a typewriter case.

RF AMPLIFIERS USING 2N544 179 The 2N544 is a p-n-p germanium-alloy drift transistor. This note discusses the use of this component in rf amplifier stages for broadcast-band radio receivers, and the performance which may be expected.

NEW RCA RELEASES 182 2N561, 2NI014 High-voltage, high-current p-n-p power transistors. 2N647 Large.signal af n·p·n transistor. 6DE4 TV damper . 6DK6 Sharp cutoff pentode. 6E88 Nigh·mu triode, s:,arp cutoff pentode. 7203/4CX2508, Ceramic and metal forced·air cooled beam power valve. 7204/4X250F 72 13 VHF beam power valve. 7262 Small vidicon for transistorized equipment. 7263 Short, rugged vidicon.

TRANSISTORS IN THE CONVERTER STAGE ...... 184 A frequency converter stage for broadcast·band radio receivers. Any one of four alternative transistors may be used. This note can be teamed with the article on the 2N544 in this issue.

RADIOTRONICS VOL_ 22, No. 10, OCTOBER 1957 - CORRECTION 185

VALVE REQUIREMENTS IN VERTICAL - DEFLECTION CI.RCUITS ... 186 In this paper, Mr. K. A. Angel of the Electron Tube Division of RCA discusses tile linearity and efficiency problems which must be considered when selecting a vertical power amplifier for TV. MUSIC AND STEREOPHONY 199 In this short article a distinguished conductor presents a musician's view of stereo, and raises several points which may have escaped the technician's notice.

OFF THE BEATEN TRACK No. 1 - THE MULTIPLIER PHOTOTUBE 201 With this item we starf a series intended to describe some of the more uncommon types of valve and valve designs. The first of the series describes the multiplier phototube, what it is, and how it works.

SPECIAL - QUALITY VALVES 204 This interesting article by Mr. J. Ziegler of AWV describes the manufacture and testing of valves designed to exhibit special qualifies of life and performance. An article of this type is rare, giving as it does an insight into the complex problems of valve manufacture.

COMPLEMENTARY - SYMMETRY 213 An explanatory note on direct coupling of p-n-p and n-p-n transistors.

NEW RCA RELEASES 214 2N456, 2N457 Germanium p-n-p switc�ing transistors. 21'1640, 2N64 J, 2N642 Germanium p-n-p transistors for car radios 2N643, 21'1644, 21'1645 Germanium p-n-p drift-switching transistors. 2N649 Germanium n-p-n large-signal transistor. 2NJ090, 2NJ091 Germanium n-p-n switching "ransistors. 4009, 4010 Travelling-wave tubes, 2000-4000 Mc. 7044 Mer:Jium-mu Twin triode for computers. 7264 14-sfage multiplier phofotube. 7265 14-sfage multiplier phototube. 7326 10-stage multiplier phototube.

NUVISTOR - THE NEW LOOK IN ELECTRON VALVES 216 The "Nuvisfor" ;s a valve design based on a new concept developed by ReA. This concept makes possible fhimble-size, more reliable and efficient, higher­ performance, and more rugged valves particularly suited for highly mechanized production. The new design is a major breakthrough in the effort to reduce size and power drain, and to increase performance and reliability.

Radiotronics is published twelve times a year by the Wireless Press for Amalgamated Wireless Valve Company Pty. Ltd . The annual SUbscription rate in Australasia is 10/-, in U.S.A. and dollar countries $1.50, and in all other countries 12/6. Price of a single copy is 1/-. Subscribers should promptly notify Amalgamated Wireless Valve Company Pty. Ltd., Box 25 16, G.P.O., Sydney, and also the local Post Office of any change of address, allowing one month for the change to become effective. Original articles in Radiotronics may be published without restrictions provided that due acknowledgement is given. Devices and arrangements shown or described herein may use patents of A WV, ReA or others. Information is furnished without responsibility by A WV or RCA for its use and without prejudice to AWV's or RCA's patent rights. Information published herein concerning new RCA releases is intended for information only, and present or future Australian availability is not implied. EDITOR .... BERNARD J. SIMPSON

PRINTED BY THE CLOISTER PRESS, 45·4� GiORGE STREET, REDFeRN SILICON POWER RECTIFIERS 227

An introduction to silicon rectifiers specially prepared for this magazine, coinciding with the increasing availability and application of these units.

NEW RCA RELEASES 232 5R4·GYB - Rectifier for stringent environmental conditions. 6FV6 - Sharp cutoff . 8HP4 - Rectangular monitor picture tube. 74J 2 - Photoconductive cell. 7448 - Display .

OFF THE BEATEN TRACK No. 2 - TV CAMERA TUBES 233

Second in this series on some of the more uncommon valves and valve designs, this article deals with the television "eye", with a brief outline of their develop· ment to complete the "picture".

NEW SILICON RECTIFIERS 237

Technical data on thirteen silicon rectifiers recently added to the Radiotron range.

TRANSISTOR PARAMETERS 241

Mr. Wilshire has performed a most useful service to readers in bringing us this article. He has revised and simplified data previously published in these pages, to provide a concise and up·to.date account, made all the more useful by the inclusion of two detailed conversion tables.

RECTIFIER VALVES AND CIRCUITS 246

This short article, written around a quick selection chart, forms the basis for easy selection of rectifiers for various types of service, based on the power requirements.

Radiotronics is published twelve times a year by the Wireless Press for Amalgamated Wirele.ss Valve Company Pty. Ltd . The annual subscription rate in Australasia is 10/-, in U.S.A. and dollar countries $1.50, and in all other countries 6. Price of a single copy is 1/-. 12/ Subscribers should promptly notify Amalgamated Wireless Valve Company Pty. Ltd., Box 25 16, G.P.O., Sydney, and also the local Post Office of any change of address, allowing one month for the change to become effective. Original articles in Radiotronics may be published without re strictions provided that due acknowledgement is given. Devices and arrangements shown or described herein may use patents of A WV, ReA or others. Information is furnished without responsibility by A WV or RCA for its use and without prejudice to A WV's or RCA's patent rights. Information published herein concerning new RCA releases is intended for information only, and present or future Australian availability is not implied. EDITOR ...... BERNARD J. $IMPSON

PRINTED BY THE CLOISTER PRESS, .,·49 Gl;; ORGE STREET, REDFERN ZENER 255 A further article in a series specially prepared for this magazine to provide for readers a survey of semiconductors and how they are being used today.

INSTALLATION AND COOLING OF SILICON RECTIFIERS .... . 260

How to instal and operate silicon rectifiers to ensure satisfactory operation and long working life.

OFF THE BEATEN TRACK No. 3 - UHF VALVES . 263

The thermionic valve for uhf applications has progressed almost out of recognition except to the specialist in this field, particularly since the introduction of metal/ ceramic valves.

NEW PUBLICATIONS 266

The following publications are reviewed this month: "Basic Radio and Radio·Receiver Servicing". "Transistor fundamentals and Applications". "Basic Electronics". "Radio Circuits - A Step by Step Survey". "Principles of Transistor Circuits".

TRANSMITTING VALVES - FREQUENCY AND POWER OUTPUT CHART 267

A useful chart designed to simplify selection of a transmitting valve when service, frequency and power output are specified.

TRANSISTOR INTERCHANGEABILITY GUIDE 271

A listing of over 500 transistors and suggested equivalents or near equivalents.

VACUUM MEASUREMENT 275

How vacuum is measured, with up·to·date technical information on the AV26 and AV34 vacuum gauges.

AV36B TUNGSTEN FILAMENT CONTROL DIODE 281

Technical data on the latest version of this diode, which forms the control element in ac regulator units.

RADIOTRONICS SUBSCRIPTIONS Subscription renewal memoranda have already been sent to overseas subscribers. A renewal card will be mailed to Australia·n subscribers during October. If you wish to receive "Radiotronics" next year, please RETURN THE CARD with your remittance before December 1 st. TRANSISTOR DISSIPATION RATINGS FOR PULSE AND SWITCHING SERVICE 287

Published dissipation ratings for class A or class 8 service with sinusoidal wave­ forms do not apply in pulsed and switching service. Data is given on the deter­ mination of suitable ratings for the latter types of services.

MIXED BASS STEREO 293

This short article discusses one way of converting to stereo at a minimum outlay.

AV43 DEMONSTRATION CATHODE RAY TUBE 296

A newly-introduced tube which will find great use in lecture-rooms, the AV43 illustrates in a novel way deflection and focusing of an electron beam.

OFF THE BEATEN TRACK No. 4 - THE MAGNETRON 301

A brief and basic description of the magnetron and its operation.

NEUTRALIZING TRANSISTOR IF AMPLIFIERS 304

An article based on a laboratory investigation carried out by AWV to examine a simpler method 01 neutralizing transistorized amplifiers.

NEW ReA RELEASES 306

2N1300, 2N1301 Germanium p-n-p transistors for high-speed switching. 7214 Beam-power valve for pulsed rl amplifier service. 7270, 7271 Beam power valves, 235 watts cw input at 175 Mc. 7358 Beam power valve, ruggedized version of 6293. 7467 Photoiunction cell. 75 13 High-quality image orthicon.

Radiotronics is published twelve times a year by the Wireless Press for Amalgamated Wireless Valve Company Pty. Ltd. The annual subscription rate in Australasia is 10/-, in U.S.A. and dollar countries $1.50, and in all other countries 12/6. Price of a single copy is 1/-. Subscribers should promptly notify Amalgamated Wireless Valve Ccmpany Pty. Ltd., Box 2516, G.P.O., Sydney, and also the local Post Office of any change of address, allowing one month for the change to become effective. Original articles in Radiotronics may be published without restrictions provided that due acknowledgement is given.

Devices and arrangements shown or described herein may use patents of A WV, ReA or others. Information is furnished without responsibility by A WV or RCA for its use and without prejudice to A WV's or RCA's patent rights. Information published herein concerning new RCA releases is intended for information only, and present or future Australian availability is not implied. EDITOR BERNARD J. SIMPSON

PRINTED BY THE CLOISTER PRESS, 45-49 GEORGE STREET, REDFERN PARAMETRIC AMPLIFIERS 31 1

The parametric amplifier is built around a p-n junction semiconductor diode designed for use at high frequencies, and in which the capacitance across the junction depends on the voltage across it. This article explains how the diode is used in building very-low-noise receivers and other equipment_

FOR SSB SERVICE 321

This article describes an extremely stable, 5-band, cathode-driven linear amplifier for 'sing/e-sideband service. This easily-constructed unit provides band-switched operation on the 80, 40, 20, J 5 and J O-metre bands.

OFF THE BEATEN TRACK No. 5 - DISPLAY STORAGE TUBES 325

In this fifth article of the series, storage tubes of the directly-viewed type are described. Storage tubes of other kinds, such as charge-storage tubes, will be covered in future articles.

NEW RCA RELEASES 329

JJ3, JK3 Half-wave HV vacuum rectifiers. 7360 Beam deflection valve. 7536 Photoconductive cell.

CUMULATIVE INDEX Lift-out Supplement

In response to demand, the usual annual index is this year replaced by a cumu­ lative index covering the years J 946- J 959 inclusive.

R adiotron ics December, Z9.j9