r

.TE

* * * * *

A * * * *

ENGINEERS choose Ohtnite prod-ucts because of their extreme de-

pendability. Today, Ohmite Rheostats,Resistors, Chokes and Tap Switches areused in endless variety and number inradio, electronic and industrial applica-tions, in planes, tanks, and ships.Widest range of types and sizes. Manystock units. Units produced to Govern-ment specifications or engineered foryou.

Send for Catalog .

Write on company hhelpful 96-page CatManual No. 40.

OHMITE MANUFAI4861 Flournoy Stre

and Manual No. 40.

!tterhead for complete,alog and Engineering gi

ITURING COMPANYaet. Chicaon. U. S. A.

Booklets, Catalogsand Pamphlets

The following commercial literature hasbeen received by the Institute.

PAPER CAPACITORS * I I Solar Manufactur-ing Corp., Bayonne, N. J. (Catalog 12-Section C, 48 pages, 82XI1 inches.) Thisis an exceptionally valuable and well illus-trated booklet on every kind of papercapacitor manufactured by this firm.Seventy capacitors are shown in photo-graphs and specifications given on hun-dreds of types. Some fine "design draw-ings" are included and every conceivableaid has been provided for quick and accu-rate selection of the type of capacitor, andits specifications is given. The back pagefeatures a clever "visual index" whichshould please any radio engineer becauseline drawings of the major classes ofcapacitors, with indexing below, make iteasy to find what you want at a glance.MICA CAPACITORS * I I Solar Manufactur-ing Corp., Bayonne, N. J. (Catalog 12-Section E, 32 pages, 8 X11 inches.) Thisbooklet is a similar treatment of MicaCapacitors to that of Paper Capacitors asdescribed above. Forty-three Mica Capac-itors are illustrated and specifications givenfor many more. The same useful back pageindex is used. Radio Engineers can obtaincopies of these catalogs by writing on theirfirm's letterhead.

PRECISION INSTRUMENTS . . . Leeds &Northrup Co., 4908 Stenton Ave., Phila-delphia, Pa. (A new company publicationcalled 'MODERN PRECISION" 16 pages,102 X 152 inches.) Describes and illus-trates in newspaper style new develop-ments in L&N instruments.

BERYLLIUM COPPER FUSE CLIPS . . . Littel-fuse Incorporated, 4757 Ravenswood Ave.,Chicago, Ill. (Specifications, 4 pages,82 X 11 inches.) Describes the unusualphysical properties of this alloy used infuse clips, to increase length of life.

ELECTRONIC LIMIT BRIDGE . . . Radio CityProducts Co., Inc., 127 West 26th St., NewYork, N. Y. (Bulletin 126, 4 pages, 82X11inches.) Describes this and other sensitivelaboratory and production instrumentsuseful to America's wartime industries.Illustrated. Prices given.DYNAMOTORS . . . General Electric Com-pany, Schenectady, N. Y. (Booklet, 4 pages,8X102 inches.) Illustrates and explainsconstruction of G-E dynamotors whichwill provide suitable voltage for radiotransmitters and receivers used in aircraft,tanks, and other mobile field and trans-portation equipment.General Electric Co., also offers an interest-ing data page entitled "G-E TransmittingTubes, Interchangeability Chart" (Page101, June 1, 1942) which radio engineersmay wish to request with above booklet.

INDIVIDUALIZED INCO NICKEL ALLOYS . . .

The International Nickel Co., Inc. 67 WallSt., New York, N. Y. (Catalog, 12 pages,

(Continued on page xxiv)Proceedings of the I. R. E. August, 1942xx

- __ _. ...

A. a.Q.,.7m itw ' t w L4A-0- 0

PRINCIPLES OF RADIO

11 .,.- .~... ..

Fourth Edition IBy KEITH HENNEY

Editor, ELECTRONICS

QJ,Ab< I,! A timely revision of a highly-success-"e | ful text. Guides the student in easy stages

e>P to a working knowledge of radio. Contains the

latest material on detection, ultra-high frequencies,

television, radio frequency amplifiers, vacuum tube de-

tectors, antennas, etc. Considers the applications of radio which

are important now.

"Henney" is the recommended textbook for the course for radiotechnicians designed for the U. S. Signal Corps and sponsoredby the U. S. Office of Education.

549 pages 51/4 x 75/8 3 16 illustrations $3.50

Copies Available on Approval

JOHN WILEY & SONS, INC., NEW YORK

(Continued from page xx)

81 XII inches.) Gives individual charac-teristics, mechanical properties and appli-cation information of various nickel alloys.Tables of physical constants and availableforms are included.

MICROPHONES AND ACOUSTICAL DEVICES* *Shure Brothers, 225 West Huron St.,Chicago, 111. (Catalog 154, 8 pages, 81X11inches.) Well illustrated and designed toaid in the proper selection of microphonesfor various War and Vital Civilian appli-cations. Includes prices.

Also there is a Shure Booklet on SUPER-CARDIOID DYNAMIC BROADCAST MICRO-PHONE which the radio engineer may wishto request at the same time.

ELECTRICAL INSTRUMENTS" Westing.house Electric and Manufacturing Co., EastPittsburgh, Pa. (Booklet B-3013, 34 pages,

8IXli inches.) Describes instruments forindustrial, central station, laboratory.portable switchboard and miniature panels,Somewhat in format as the quick selectorcatalog, the new booklet lists all instru-ment types for specific applications on an

instrument selector chart. Illustrations in-clude 120 photographs, 44 representativemeter dials and 13 types of strip and circu-lar charts. Address requests to department7-N-20.

DELAY RELAYS.* Amperite Corp., 561Broadway, New York, N. Y. (Data Sheets,3 pages, 8j XII inches.) Covers relays anddelay relays sealed in glass bulb. Anotherdata sheet covers ballast tubes, and a thirdgives specifications on ballast tubes for

xxiv

automatic regulation of current and volt-age.

THE OHMITE NEwS* *Ohmite Manufac-turing Co., 4835-41 Flournoy St., Chicago,Ill. (House Organ, 2 pages 8iX11 inches.)February issue gives brief biography ofWilliam Duddell and discusses the Dud-dell Oscillograph and Thermo-talvanome-ter. March issue describes an Ohm's LawCalculator offered by Ohmite for soldiersand sailors in training schools. April Issuereports on Ohmite Rheostats. May issuegives applications for fixed lug type re-

sistors.

BATTERY REPLACEMENT CHART Radio& Technical Publishing Co., 45 Astor Pi.,New York, N. Y. (Wall chart, 1 sheet,20j X 17 inches.) Designed for service menbut may be useful to radio engineers indetermining batteries for 1250 models ofportable radio receivers. Mailing cost 100WIRE DATA. . . Callite Tungsten Corp.,544 39th St., Union City, N. J. This firmoffers radio engineers a free chart consist-ing of three tables giving diameters,weights, conversion factors and physicalproperties of wire for aid in designs andspecifications. Two sizes are available, a

hand sized celluloid card, and a wall chart,36X21 inches.

THE GENERAL RADIO EXPERIMENTER...General Radio Co., 30 State St., Camnbridge,Mass. (House Organ, 6 X9* inches.) MarchIssue gives 12 interesting pages on "HowGood Is An Iron-Cored Coil?" April Issuecovers 'Increased Power-Factor Range forthe Capacitance Bridge" and other sub-jects.

INDEXPositions Open ...................... xxiiiBooklets and Pamphlets ................ xx

DISPLAY ADVERTISERS

AAerovox Corporation ................... iiAmerican Lava Corporation ..............

v

American Telephone & Telegraph Co viii

BBliley Electric Company ................

xx

C

Capitol Radio Engineering Institute xviCentralab ........ xviiCornell-Dubilier Electric Corp.. Cover III

DDaven Company ........................ i

GGeneral Electric Company .xiiiGeneral Radio Company .......... Cover IV

HHeintz & Kaufman, Ltd. .................

x

Hewlett-Packard Company ............ xxiiiHytron Corporation .................... ix

International Resistance Company .......

International Telephone & Telegraph Corp. viiIsolantite, Inc. ....................... xix

0

Ohmite Manufacturing Company ........ xx

pPremax Products ..................... xviii

RRaytheon Manufacturing Company ....... iRCA Manufacturing Company, Inc ... xxvi

John F. Rider Publisher, Inc ...........xxii

S

Shallcross Manufacturing Co .......... xviii

Solar Manufacturing Corporation .......xxii

Sprague Specialties Company ....... iii, xxv

T

Thordarson Electric Mfg. Company ...... xviTriplett Electrical Instrument Co ......... iv

U

United Transformer Company ...... Cover 11

w

Westinghouse Electric & Mfg. Co. xxi

John Wiley & Sons, Inc. ..............

xxiv

Proceedings of the I. R, E. August, 1942

NOTEThe American Lava Corporation has ex-pressed great regret that its June adver-tisement in PROCEEDINGS of the I.R.E.was, in part, a copy of an admirable in-stitutional advertisement previously usedby the Varnish Products Company ofCleveland, Ohio. This inadvertence is con-trary to their long established policy andthey wish by this means to give due creditto the originator of such a brilliant in-spiration.