Indianapolis Times, Volume 36, Number 236, Indianapolis, Marion County, 12 February 1925 — Page 15

New Vacuum Tube Is Being Built —Has New Features

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This drawing will give the reader an idea as to what the new 110-volt vacuum tube will be like. The heating element in the center is removable so that anew one can be inserted, wehn the one In use burns dut.'This element serves

,• *•' - . f- 4 ’ *•/ ■■■ .. D *9o=l $17.00 Down* $2.00 Per Week fWßiri WBSBBB&KWfam* ■HHBH 11SH I aBHBBjM f J. M II If I Q it 90 w UNIDYNE Combination Radio and Phonograph S2OO Complete, Installed $40.00 Down $5.00 Per Week ——— ~ NEUTRODYNE *l6s^ $33 Down $4.00 Per Week

SLEEPER-MONOTROL , One Dial, Four Tubes, $l9O Complete

After testing a great many different receiving sets these have been selected on account of ease of operation, selectivity; tone quality and volume. INDIANAPOLIS MUSIC HOUSE 134 North Pennsylvania St. PtANOS VICTROLAS Open Evenings MAin 2188

only to heat the cathode element which provides the nec ssary emission of electrons. The development of the equipment used in radio broadcast stations and receiving sets has been more than rapid—it has been phenomenal. Al-

TIIE INDIANAPOLIS TIMES

RADIO IN THE HOMES

HOW NEARISTHE SATURATION POINT IN RADIO? a,000,000 HOMES 3,000,000 HOMES WITHOUT RADIOS WITH RADIOS O RADIO NEWS

most daily new circuits or apparatus are announced to the public and the outfits of yesterday are declared obsolete. However, there has been one piece of apparatus that has become almost standardized—the three element vacuum tube. It is true that refinements have been introduced, but the tube itself remains unchanged. At present there is a vacuum tube in the process of development in which there is Incorporated a radical change in construction. The tube is so designed that it will operate from the 110-volt house current with no supplementary devices. Think what a step forward this is! No more storage batteries to worry over and no more sore arm muscles caused by carrying home fresh supplies of dry cells. All that is needed is to plug in on the house current and the tubes will operate. The tube may be operated from either an A. C. or D. C. supply, and as this current does not enter into the circuit of the set, it may be used as the “B” battery, with proper filters. The entire structure of the tube is new, except the familiar grid and plate. The base fits a standard Edison light socket instead of the present type of tube sockets. An advantage arising from this is that the grid and plate leads are kept separate, being brought through the top of the tube. Until now the noises from tubes operated from lighting circuits have been excessive, but there is a complete elimination of “hum” or “ripple” with this tube. One of the greatest advances made in the construction of this tube is that the filament or heating element is renewable at a small cost. However, this need not alarm the fan, as the heating element is said to have ten times the life of the present day filaments. Also the electronic emission is almost indefinite, so there is no danger of the tube going “dead” suddenly. As may be seen in the accompanying sketch, there are three indentations in the glass bulb, through which, are brought the grid plate, and cathode leads. The exhaustion tip is at the lower side of the tube. A thin quartz tube is fastened to

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the base and extends up into the tube. This quartz tube is sealed at the upper end and is open at the lower end to permit the insertion of the heating element. This element is formed of Nichrome resistance ribbon spirally wound on an “alundum” rod, which is made fast to the base by the screw in the bottom. The electrical connections tp the heating element are made to the base screw as in an ordinary electric lamp. There is an “alundum” sleeve that fits tightly over the quartz tube in side the evacuated bulb and this is the cathode or electron source, corresponding to the filament of the present-day vacuum tubes. The heating element within the quartz tube heats this “alundum” sleeve to a red heat, in which state it becomes an excellent emanator of electrons. The grid of the tube Is a ne wire mesh cylinder, suspended from the top of the bulb by its connecting wire. The grid is in the usual place between the cathode and the plate, which is a metal cylinder and also suspended from the bulb’s top by its connecting wire. When the current is applied to the tube the heating element becomes red hot. The heat is conducted through the quartz tube to the “alundum” sleeve "or cathode, which is heated to a dull red temperature. In this state “alundum” becomes an excellent emitter of electrons and because of the large surface of the cathode a greater number of electrons are emanated per unit area per unit of Input energy. This method of heating the cathode is the only change in the tube’s operation, the remaining action being the same as a C-301A or any other tube. The current consumption of the tube’s heating element is about the same as a 50-watt lamp, which costs about one-half cent an hour to operate. Information for Sale German broadcasting stations are selling agricultural, stock and other information by radio. Prices and other data are broadcasted in code to subscribers. The code is changed at regular intervals.

By Roy Grove

'JPntn&'A Radio Dept, Illinois & Wash. St. Store

New Panstiehl 3 Circuit Tuner No. P-300 fir Low Loss Low Price This tuner solves the difficulties of radio. 1. The aperiodic primary prevents reradiation. 2. The three-circuit tapps insures selectivity. 3. The new low-ioss feature of staggerwound, no dielectric or absorption material in field, and the compact but not-scattered field produced, means anew and supreme efficiency. 4. A set built with this tuner will not radiate and drive your neighbor to bed, as sets built of two rotor construction or of similar tuning are apt to-do. A Complete Kit for One-Tube Set 1 Panstiehl Tuner 0-302 $5.00 1 Cardwell Condenser .00035 , $4.75 1 Dial, 4-inch, with Vernier SI.OO 1 Benjamin Socket SI.OO 1 Carter 6 ohm Vernier Rheostat $1.75 1 Dubilier 1 Daven Grid Leak .........50* 1 Dial, 4-Inch 50* 7 Eby Post. Engraved .. $1.40 1 Panel, 7x9 75* Bus Wire and Brackets FREE Price.. $16.40 _ Radiotron Cunningham j$ Tubes, \ All Sizes Buy Batteries Only by Meter Test. $3.75 Ever-Ready and Ray-O-Vac B Batteries, 45 Volts... .$3.84 $2.00 Ever-Ready and Ray-0-Vac B Batteries, 22% V01t5..51.74 60c Ever-Ready and Ray-O-Vac C Batteries, 4% Volta 49c

S. R. S. Loud Speaker A Speaker of Quality, Guaranteed 7.98

$9.00 Rauland Lyric Transformers $7.98 $7.00 Karas Transformers $5.88 $5.00 Remler Condensers .0005. .$3.98 $7.00 National Condensers with Vernier Dials $5.98 $6.00 National Condensers with Vernier Dials $4.74

Look Up the BARGAIN TABLE Standard parts at moneysaving prices. Absolutely no salvage.

Open Evenings, Sundays

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