TM (triode)

The triode TM was developed in 1914-1915 by the French military signalmen at the initiative of Colonel frété Télégraphie Militaire ^{[2] [3]} . Ferrier and his closest assistant, physicist , repeatedly visited American laboratories and were well aware of the works of Lee de Forest , Reginald Fessenden and Irving Langmuir ^{[4] [5]} . Ferrier and Abraham knew well that the “ audion ” de Forest and the British lamp of were unreliable and imperfect, and the Langmuir pliotron was too complicated for mass production ^[4] . They also knew about the state of the latest German developments: shortly after the start of the war Ferrier received comprehensive information from a former Telefunken employee, Frenchman Paul Pichon ^{[6] [7] [8] [9] [k. 1]} . Pishon brought in from the USA the latest models of American triodes, but even they turned out to be unsuitable for use in the army ^{[8] [6]} . The culprit of the unpredictable behavior of the lamps was not a deep vacuum ^{[6] [5] [c. 2]} . Following the ideas of Langmuir, Ferrier made the right decision - to achieve guaranteed deepness from industry ^{[to. 3]} vacuum in serial production. The French triode was supposed to be reliable, stable and suitable for mass production ^[9] .

In October 1914, Ferrier sent Abraham and technologist Francois Perry to the Grammont Electric Lamp Factory in Lyon ^{[11] [8]} . Through trial and error, Abraham and Peri were able to find the optimal triode configuration suitable for mass production ^{[12] [8]} . The first samples, literally copying the “audio” de Forest, turned out to be unreliable and unstable ^[8] . Langmuir's Plyotron was functional, but extremely complex; for the same reason, the French rejected the first samples of their own design ^[8] . Only the fourth prototype, developed in December 1914 ^[13] , with a vertically arranged cylindrical anode , was suitable for serial production ^[8] . This development of Abraham and Peri (“the lamp of Abraham”) went into series in February 1915 and was released until October 1915 ^{[13] [8]} .

Actual operation revealed the weakness of the vertical structure: many lamps were damaged during transportation to the troops ^{[14] [8]} . Ferrier ordered Peri to immediately rectify the situation, and two days later, Peri and Jacques Biguet presented a new design of the same lamp, with a horizontal orientation of the anode-cathode assembly and the latest four-pin base type “A” (in the “Abraham’s lamp” the usual Edison base was used with additional side conclusions of the anode and grid) ^{[14] [8]} . Serial production of the lamp of Peri and Biquet began in November 1915 - it was this option that became the main one and received the designation TM ( French Télégraphie Militaire ) by the name of the service headed by Ferrier ^{[15] [8]} .

The work of Ferrier and Abraham in the field of radio communications was awarded a nomination for the Nobel Prize in Physics in 1916 ^[16] , and Peri and Bige received the patent for the invention of the triode, which subsequently led to lawsuits from colleagues who remained out of work ^{[17] [18 ] [18 ] ] [to. 4]} .

TM is a triode of an almost perfect cylindrical design. The direct cathode is a filament of undoped tungsten with a diameter of 0.06 mm, the anode is a nickel cylinder with a diameter of 10 mm and a length of 15 mm ^{[20] [21]} . The size and material of the mesh depends on the place of production: the factory in Lyon used molybdenum wire, the factory in Ivry-sur-Seine used nickel ^{[20] [22]} . The diameter of the mesh spiral is 4 or 4.5 mm ^{[20] [22]} .

In order to heat a pure tungsten cathode to white heat , a current of 0.7 A was required at a rated filament voltage of 4 V ^{[20] [22]} . The red-hot cathode glowed so brightly that in 1923, the Grammont factory began producing TM with dark blue glass flasks ^{[20] [23]} . According to one version, this did not allow the use of expensive triodes as ordinary lighting lamps , according to another - it protected the eyes of radio operators from bright light - but the most likely reason was that the dark glass masked a harmless but unsightly plaque of metal particles, which inevitably deposited on the inner wall of the bulb when pumping the lamp ^{[20] [23]} .

The TM triode and its later versions were universal: they could be used for their intended purpose — to amplify and detect signals in radio receivers, and as generators of low-power radio transmitters , and when several lamps are switched on in parallel, and as low-frequency power amplifiers ^[24] . The Soviet analogue of ТМ, the R-5 triode, in the generator mode withstood anode voltages of up to 500 ... 800 V, and was able to transmit vibrational power up to 1 W to the antenna (in the nominal amplification mode in mode A - no more than 40 mW) ^[25] .

In a typical one-tube radio receiver of the First World War, a voltage of 40 V was applied to the TM anode; at zero bias on the grid, the anode current was about 2 mA ^{[20] [22]} . In this mode, the steepness of the anode-grid characteristic of the triode was 0.4 mA / V, the internal resistance was 25 kOhm , and the gain (μ) was 10 ^{[20] [22]} . At a voltage of 160 V at the anode and a bias of −2 V, the current was 3 ... 6 mA, while the reverse current of the grid reached 1 μA ^{[20] [22]} . Significant grid currents, facilitating the bias by a grid resistor , are a consequence of the imperfect technology of the 1910s ^[22] .

The disadvantage of TM was a short service life, not exceeding 100 hours, if the lamp was manufactured in strict accordance with the technical conditions ^[22] . In wartime, this was not always possible: due to difficulties in supplying plants, from time to time they switched to substandard raw materials ^[22] . Lamps made from it were marked with a cross; they differed from the standard ones by a high noise level and were subject to catastrophic failures due to cracks in the glass ^[22] .

TM turned out to be so successful for its time that it was supplied not only to the French armed forces, but to all Entente states ^[18] . The Lyon plant did not have enough capacity, and already in April 1916 the production of TM began at the plant in Ivry-sur-Seine ^[18] .

TM production volume is not reliably known, but for its time it was unprecedentedly large ^[26] . Estimates of the daily release of TM at the end of the war range between one thousand (only Grammont plants) and six thousand lamps ^[26] . According to Grammont engineer Rene Wild, over the years of the war, only a plant in Lyon produced 1.8 million TM ^[27] . According to the conservative estimate of Robert Champaign, the factory in Lyon produced about 800 thousand lamps, the factory in Ivry-sur-Seine - 300 thousand ^{[27] [18]} . For comparison, the military order of the US Department of Defense in 1917 amounted to only 80 thousand lamps ^[28] . This was too little for warfare; US expeditionary force in France used French TM ^[28] .

The British, having received the first TM models, recognized the superiority of the French design over their own developments and already in 1916 launched their own TM production ^[10] . Technology and technological equipment was developed by , and the main manufacturer was the Osram-Robertson electric lamp factory (the core of the future ) ^[29] . The British version of TM was named the "R Series" ^[29] . In 1916-1917, Osram produced two structurally indistinguishable lamp variants - “hard” R1 (exact copy of TM) and “soft” R2 filled with nitrogen . She became the last in British practice "soft" (gas) lamp; all subsequent lamps of the “R series”, up to and including R7, were classical “rigid” (vacuum, not gas) triodes ^[29] . A cylindrical design dating back to the Abraham and Peri lamp was also used in British generator lamps, up to the 800-watt T7X ^[30] . Variants of lamps of the “R series” by British order were produced in the USA at the Moorhead factory, and after the war - at Philips factories in the Netherlands , under the name “E series” ^[20] .

Russian military and engineers received the first samples of TM in 1917 ^[1] . In the same year, M. A. Bonch-Bruevich attempted to create a “French-style lamp” in the workshops of Tver Radio Station ^[1] . Large-scale production became possible only in 1923, after the acquisition of the Electrosvyaz trust of French technical documentation ^[31] . The Soviet industrial analogue TM was named R-5 and P7, and the economical version with a thoriated cathode was called Micro. The only manufacturer of these lamps was the Leningrad Electrovacuum Plant ^[32] (which later became part of Svetlana ).

TM left the stage gradually - as specialized radio tubes appeared, which performed their functions better than the universal TM and its analogues ^[24] . In the USA and countries of Western Europe, the change of generations of lamps ended in the 1920s, in the relatively backward USSR, it began only in the late 1920s ^[24] . Exact information on the termination of TM production has not been preserved; according to Champaign, in France it lasted until 1935 inclusively ^[20] . After World War II, TM and R-series replicas were issued at least twice - by the amateur workshop of Rüdiger Waltz ( Germany , 1980s ^[33] ) and KR Audio ( Czech Republic , since 1992 ^{[34] [K. 5]} ) .

• Mark, M.G. Our lamps // Radio amateur. - 1929. - No. 5. - S. 183-188.
• Berghen, Fvd About the French TM Valve, the Forerunner of the R-Valve // British Vintage Wireless Society magazine. - 2002. - No. 2. - P. 20-23.
• Champeix, R. Grande et Petite Histoire de la LampeTM // Bulletin de Liaison. - 1980. - No. Nov-Dec. - P. 1-48.
• Ginoux, J.-M. History of Nonlinear Oscillations Theory in France (1880-1940) . - Springer, 2017 .-- ISBN 9783319552392 .
• Vyse, B. Marconi Osram Valve. Extracts from 'The Saga of Marconi Osram Valves' // British Vintage Wireless Society magazine. - 1999. - No. 4. - P. 12-20.