VOL. 14 No. 5, pp. 117·152 NOVEMBER 1952 Philips Technical Review DEALING ~TH TEC~~CAL PROBLEMS RELATING TO THE PRODUCTS, PROCESSES AND INVESTIGATIONS OF THE PHILIPS INDUSTRIES EDITED BY THE RESEARCH LABORATORY OF N.V. PHILIPS' GLOEILAMPENFABRIEKEN. EINDHOVEN.NETHERLANDS ELECTRONIC TUBES A synopsis hy J. L. H. JONKER 621.385 The following article covers the main points of ctn address by Prof Dr. J. L. H. Jonker on his formol acceptance ofthe office of professor at the Technical Un iuersiiy at. Delft on 19th March 1952. Although the extent of his subject did not admit of more tluin a brief review, this "bird's-eye view", which brings mall)' ioulelv separated aspects into (/ common focus, has an appeal of its 01011. Nothing hut the greatest admiration can be felt It was roughly at the turn of the century that by anyone tracing the rapid development of elcc- Hertz, Sir OliveI' Lodge and Marconi carried tronies, that is, electronic tubes and their applica- out the experiments that led to the successful tions, which has sprung from the phenomenal introduetion of telegraphy without wires by means growth of radio in the first half of the twentieth of high-frequency oscillations. century. In the short span of a few decades radio has 118 PHILIPS TECHNICAL REVIE W VOL. 14, No. 5 undergone almost unbelievable technical develop- "so outstanding in its consequences that it almost ment and improvement, and it has achieved a ranks with the greatest inventions of all time". revolution in the interchange of ideas between This invention is the triode of Lee de Forest. individuals and peoples alike. It has come to assume The advent of the triode such importance in the lives of almost everyone that throughout the whole evolution of mankind In seeking for a better detector of radio signals there have been few technical developments to Lee de Forest 2) in 1907 introduced a grid between equal it. the cathode and anode of the existing diode devised by Sir John Ambrose Fleming, thus obtaining The early days of radio a means of controlling the flow of electrons between This development of radio, which took the world by storm, founds its origin in the experiments al- ready mentioned. Channels were established across the oceans, first telegraphically and later by tele- phone, up to the point where radio contact now covers the whole glo~e. In the early years, technical knowledge and literature on the subject were in the nature of things very limited. Because the individual experimenter was, however, in very Juany instances able to achieve valuable results and improvements using only simple and often home-made equipment, many felt themselves drawn towards this sphere and this is undoubtedly one of the causes of the very rapid advances made. Those who were privileged to witness at close quartcrs some part of this inspmug early period may look back on those exciting days with some rcgret, comparing them with conditions as they are today. now that improvement and research into specific problems are in thc hands of a corps of specialists having the most ingenious laboratory equipment at their disposal. As a result of the work of these specialists, Fi~. 1. The ori~illal triode C'audioll") of I,ee dl' Forest. literature on the subject of radio would now con- stitute a whole library in itself, whereas, on the other hand, thc ceaseless flow of publications cathode and anode without the cousurnption of auy presents to the expert the problem of keeping in energy (figs 1 and 2). Years elapsed before the touch with everything that is of interest in his operation and possibilities of this new invention work. Here, too, a too copious emission results in were fully appreeiated, in consequence of which so great a space charge that the ultimate object is De Forest became so short of funds that he had to defeated. In the United States this urgent problem let his European patents lapse! In 1911 Robert has recently given rise to an investigation into the von Lieben gave a demonstration of the ampli- statistical distribution of such publications among fication properties of the triode at the Berliner the various periodicals; the result of this investiga- Physikalische Gesellsehaft. In 1913different research tion has been reported - in another publication! - workers simultaneaously invented the "feed-back", in the periodical containing the largest number of which permitted the triode to he used as a very such publications 1). effective g en er a t 0 r of high-frequency oscillations. It is because of the initial circumstances already The last-mentioned invention gave rise to the outlined that history can point to one specific longest case of patents litigation in this field in invention of one man, as being as it were the lever history ~), a contest which was not settled until which released radio from its trammels. This was 1934, in favour of De Forest. the start of the subsequent fantastic growth and The invention of the triode, which marked the was, in the words of the Nobel-prize winner Ra b i: commencement of the electronic era, gave to radio - ,.,., -,- NOVEMBER 1952 ELECTRONIC TUBES 119 at once a better detector, the long sought amplifier reproduction and the oscilloscope. In the years and an oscillator. These various possibilities provid- that. followed, research penetrated the realms of ed the stimulus for a careful study' of these tubes ultra-short waves, atmospheric interference, fre- and for such modifications as would ensure optimum quency modulation and television, apart from in- results in any function in transmitting and receiving numerable industrial applications of electronics. In equipment, and this has in turn produced the Ill- each case the electronic tube was the key that nu~erable varieties of electronic tubes which we opened the door to the new sphere, and .often,- know today." in new forms, to entirely new possibilities. This r .....fuN '70.~ -,I when ~d oondOJ'OOr is ~L OTer the dUcling member from ....-'"z; ·ltAIHO TI:I":PIl(l:\t: A ClJl'IIQ!tATION SEW "ORK .~R~~~~~\~:~:~~;~~'~':~~:~N~::~~"~ro , or 8Ounu.. produced therein under the Mm~ eon- chnrg"d. diLiona wllen Mid eondenser ia not employed. 'P~OK TIU.JI:Oa·~PBT. ;. An oscillation d, h will be understood thaL Lh. drcuil ar- P\'IiCUa.'4>t1 veSMI incl. l ra.ngemenls herein described with reference J:a8I.'O\l8 ... I7O,ua. 'lpec:tGoaUoa of 1A\t4.n ~&~t.. ducting me-di Pa&.ea.M4 hbo 1',1001 to the part.icular (Ofins ol audion herein dis- ruetubera inclosed the l":kalJ ... 1.. J..... 1l 211.1107. 8.,t&l I,. nUI2. eloeed lDay wiUI acJvänla~e also be employed tiun eircuit, a circuit c with v.riuu" other l\'IIt":J uIalIdion. • ol tl8ÏtI oscäleticn cie. To .11 tI\\om il may con",,",: Iclt.iw: . end bruughL uut to the temunal 3. Inter- u 1II('1II1wnt, a <lJnd"llaf'r BtI it known tbat 1, t..Kf."lIt: l-'uKt:,.T, a citi- posed between tho mrruhcn lo' and" i.a a ~d. nal.intlirating t1rvi('t, aeD the ~'ni;<N1 Slat ....H, 1\1111 & rr- ..itlt'Hl of av!~u~uJ or !Shart.od member 0, which m.\' 1.M· lurmoo ot 10 ~t~l~ ;~~~~I~i~~Î~i~~:c.~iug tulicl tIrvit' e w ith OD N"w York,.tn Loo county "r ~I'W )'urk aml ,IatinuIII ~'il"t', and ,,'h.rh· haR one find in, means for Ill'ati~ tUti,1 electrode, a second anti witb thp thir.1 rnen 6 Htae.. uf XI'W '\' nrk I luwe iu\ ,'uh'cl rt IU"Y, .1\11 1'TtluJ:hl 'tut to ttu- tC"Tlllinal I Thu IU('DIre- elecLrocJe inclosed "Ithin said V688f'., a 1000öl ~, An «ecllletion d, u.lul hnpl'\I\"'lIuont in'Spat'" Trl""'Ttt.phy. (ff l'f!ivinJ{ I"lfl'UII, which includes the ha'tery B, '0 circuit h"VÏJ~ its (A'nnÎnals electrically con- evecunt ..d ,'('&wl. L" wbkh the r.tlluwillg i~K :i1H'I-ilif'lItIHII ur othor l'iuilHhlo :44ll1rC6 ", elt'('tr.'llIoti"e th,·rl·in. IIIl'nnd fur het 1r. If,)' in"("11111111 n-latA·!'o tu "in'II'~'" tl·II·~r8ph (or~I" und 1111'~iKlIl1l illtlÎt'atinj: device T, ~':c~~:l\\~iIÖ~i~~':!:i:i~,,~:.t~~~,irf~~:t';Jtru,lt'rI,11 ('''ntllll'lill~ n ~IYen4 IIr u."'4'iIItt.11111l fl.'lt·c·tllr", uf a ""H' ,,-1111 h IIltlJ' I,., It. lt·h't.hllll(' ..,·I·... ver, h... it. bet ....eon said electredes. It.ntl lllfOlilL"" lor cun- !Wid \·,·~·I aml interpc 10 hef1'lofure cl~·ribf.cJ in lily prlur 1...11.4'04 P.l- t.çrlllill~IM C·IIIIIII.ru:d Lu tIIl'J'I.t" 6 .n~ ma· ...eying the 06c.:Ütati'lfl:l to he tlt'lA'ctfOd to till' tn!tl(':!., IIU'I\IIK fllr ,'still ~ut Ne... S14,U:i7, ,IUIIf' :W. 1!IIHi HIIII ':U;,Oif), IIH'nl ~ ut till! 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