TM (triode)
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The TM (from french: Telegraphie Militaire, also marketed as ''TM Fotos'' and ''TM Metal'') was a
triode A triode is an electronic amplifying vacuum tube (or ''valve'' in British English) consisting of three electrodes inside an evacuated glass envelope: a heated filament or cathode, a grid, and a plate (anode). Developed from Lee De Forest's 19 ...
vacuum tube A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric voltage, potential difference has been applied. The type kn ...
for amplification and
demodulation Demodulation is extracting the original information-bearing signal from a carrier wave. A demodulator is an electronic circuit (or computer program in a software-defined radio) that is used to recover the information content from the modulated ...
of radio signals, manufactured in
France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...
from November 1915 to around 1935. The TM, developed for the
French Army The French Army, officially known as the Land Army (french: Armée de Terre, ), is the land-based and largest component of the French Armed Forces. It is responsible to the Government of France, along with the other components of the Armed For ...
, became the standard small-signal radio tube of the
Allies of World War I The Allies of World War I, Entente Powers, or Allied Powers were a coalition of countries led by France, the United Kingdom, Russia, Italy, Japan, and the United States against the Central Powers of Germany, Austria-Hungary, the Ottoman Em ...
, and the first truly mass-produced vacuum tube. Wartime production in France is estimated at no less than 1.1 million units. Copies and derivatives of the TM were mass-produced in the
United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...
as Type R, in the
Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...
as Type E, in the
United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
and in
Soviet Russia The Russian Soviet Federative Socialist Republic, Russian SFSR or RSFSR ( rus, Российская Советская Федеративная Социалистическая Республика, Rossíyskaya Sovétskaya Federatívnaya Soci ...
as P-5 and П7.


Development

Development of the TM was initiated by colonel
Gustave-Auguste Ferrié Gustave-Auguste Ferrié (19 November 1868 – 16 February 1932) was a French radio pioneer and army general.
, chief of French long-distance military communications (''Télégraphie Militaire''). Ferrié and his closest associate
Henri Abraham Henri Abraham (1868–1943) was a French physicist who made important contributions to the science of radio waves. He performed some of the first measurements of the propagation velocity of radio waves, helped develop France's first triode vacu ...
were well informed about American research in radio and vacuum technology. They knew that
Lee de Forest Lee de Forest (August 26, 1873 – June 30, 1961) was an American inventor and a fundamentally important early pioneer in electronics. He invented the first electronic device for controlling current flow; the three-element "Audion" triode va ...
's
audion The Audion was an electronic detecting or amplifying vacuum tube invented by American electrical engineer Lee de Forest in 1906.De Forest patented a number of variations of his detector tubes starting in 1906. The patent that most clearly covers ...
and the British gas-filled lamp designed by
H. J. Round Captain Henry Joseph Round (2 June 1881 – 17 August 1966) was an English engineer and one of the early pioneers of radio. He was the first to report observation of electroluminescence from a solid state diode, leading to the discovery of the l ...
were too unstable and unreliable for military service, and that
Irving Langmuir Irving Langmuir (; January 31, 1881 – August 16, 1957) was an American chemist, physicist, and engineer. He was awarded the Nobel Prize in Chemistry in 1932 for his work in surface chemistry. Langmuir's most famous publication is the 1919 art ...
's pliotron was too complex and expensive for mass production. Shortly after the outbreak of
World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
, a former
Telefunken Telefunken was a German radio and television apparatus company, founded in Berlin in 1903, as a joint venture of Siemens & Halske and the ''Allgemeine Elektrizitäts-Gesellschaft'' (AEG) ('General electricity company'). The name "Telefunken" app ...
employee returning from the United States briefed Ferrié on the progress made in Germany and delivered samples of the latest American triodes, but again none of them met the demands of the Army. The problems were traced to insufficiently hard
vacuum A vacuum is a space devoid of matter. The word is derived from the Latin adjective ''vacuus'' for "vacant" or "void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Physicists often dis ...
. Following suggestions made by Langmuire, Ferrié made a strategically correct decision to refine industrial
vacuum pump A vacuum pump is a device that draws gas molecules from a sealed volume in order to leave behind a partial vacuum. The job of a vacuum pump is to generate a relative vacuum within a capacity. The first vacuum pump was invented in 1650 by Otto v ...
technology that could guarantee sufficiently hard vacuum in mass production. The future French triode needed to be reliable, reproducible and inexpensive. In October 1914 Ferrié dispatched Abraham and Michel Peri to Grammont incandescent lamp plant in
Lyon Lyon,, ; Occitan: ''Lion'', hist. ''Lionés'' also spelled in English as Lyons, is the third-largest city and second-largest metropolitan area of France. It is located at the confluence of the rivers Rhône and Saône, to the northwest of t ...
. Abraham and Peri started with copying American designs. As was expected, the audion was unreliable and unstable, the pliotron and the first three original French prototypes were too complex. By trial and error, Abraham and Peri developed a simpler and inexpensive configuration. Their fourth prototype, which had vertically placed electrode assembly, was selected for mass production and was manufactured by Grammont from February to October of 1915. This triode, known as the ''Abraham tube'', did not pass the test of field service: many tubes were damaged during transportation. Ferrié instructed Peri to fix the problem, and two days later Peri and Jacques Biguet presented a modified design, with horizontally placed electrode assembly and the novel four-pin ''Type A''
socket Socket may refer to: Mechanics * Socket wrench, a type of wrench that uses separate, removable sockets to fit different sizes of nuts and bolts * Socket head screw, a screw (or bolt) with a cylindrical head containing a socket into which the hexag ...
(the original Abraham tube used an
Edison screw Edison screw (ES) is a standard lightbulb socket for electric light bulbs. It was developed by Thomas Edison (1847–1931), patented in 1881, and was licensed in 1909 under General Electric's Mazda trademark. The bulbs have right-hand threaded ...
with two additional flexible wires). In November 1915 the new triode was pressed into production and became known as the TM after the French service that developed it. Work by Ferrié and Abraham was nominated for the 1916
Nobel Prize in Physics ) , image = Nobel Prize.png , alt = A golden medallion with an embossed image of a bearded man facing left in profile. To the left of the man is the text "ALFR•" then "NOBEL", and on the right, the text (smaller) "NAT•" then " ...
. However, the
patent A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an enabling disclosure of the invention."A p ...
was granted solely to Peri and Biguet, causing future legal disputes.


Design and specifications

The electrode assembly of the TM has nearly perfect
cylindrical A cylinder (from ) has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base. A cylinder may also be defined as an infini ...
shape. The
anode An anode is an electrode of a polarized electrical device through which conventional current enters the device. This contrasts with a cathode, an electrode of the device through which conventional current leaves the device. A common mnemonic is ...
is a
nickel Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow to ...
cylinder, 10 mm in diameter and 15 mm long. Grid diameter varies from 4.0 to 4.5 mm; the Lyon plant made grids of pure
molybdenum Molybdenum is a chemical element with the symbol Mo and atomic number 42 which is located in period 5 and group 6. The name is from Neo-Latin ''molybdaenum'', which is based on Ancient Greek ', meaning lead, since its ores were confused with lea ...
, the plant in
Ivry-sur-Seine Ivry-sur-Seine () is a commune in the Val-de-Marne department in the southeastern suburbs of Paris, France. It is located from the centre of Paris. Paris's main Asian district, the Quartier Asiatique in the 13th arrondissement, borders the co ...
used nickel. The directly-heated
cathode A cathode is the electrode from which a conventional current leaves a polarized electrical device. This definition can be recalled by using the mnemonic ''CCD'' for ''Cathode Current Departs''. A conventional current describes the direction in whi ...
filament is a straight wire of pure
tungsten Tungsten, or wolfram, is a chemical element with the symbol W and atomic number 74. Tungsten is a rare metal found naturally on Earth almost exclusively as compounds with other elements. It was identified as a new element in 1781 and first isolat ...
, 0.06 mm in diameter. Pure tungsten cathode reached proper emission level when heated to white incandescence, which required heating
current Currents, Current or The Current may refer to: Science and technology * Current (fluid), the flow of a liquid or a gas ** Air current, a flow of air ** Ocean current, a current in the ocean *** Rip current, a kind of water current ** Current (stre ...
of over 0.7 A at 4 V. The filament was so bright that in 1923 Grammont replaced clear glass envelope with dark blue
cobalt glass Cobalt glass—known as "smalt" when ground as a pigment—is a deep blue coloured glass prepared by including a cobalt compound, typically cobalt oxide or cobalt carbonate, in a glass melt. Cobalt is a very intense colouring agent and very littl ...
. There were rumours that the company tried to discourage alleged use of radio tubes in place of lightbulbs, or that they tried to protect the eyes of radio operators. Most likely, however, dark glass was used to mask harmless but unsightly metal particles that were inevitably sputtered on the inner surface of the bulb. A typical single-tube radio receiver of World War I used 40 V plate power supply ( B battery) and zero bias on the grid (no
C battery The C battery (C size battery or R14 battery) is a standard size of dry cell battery typically used in medium-drain applications such as toys, flashlights, and musical instruments. As of 2007, C batteries accounted for 4% of alkaline primary ...
required). In this mode, the tube operated at 2 mA standing anode current, and had
transconductance Transconductance (for transfer conductance), also infrequently called mutual conductance, is the electrical characteristic relating the current through the output of a device to the voltage across the input of a device. Conductance is the reciproca ...
of 0.4 mA/V, gain (μ) of 10 and anode impedance of 25 kOhm. At higher voltages (i.e. 160 V on the anode and -2 V on the grid), standing plate current rose to 3...6 mA, with reverse grid current up to 1 μA. High grid currents, an inevitable consequence of primitive technology of the 1910s, simplified grid leak biasing. The TM and its immediate clones were general-purpose tubes. In addition to their original radio receiving function, they were successfully employed in radio transmitters. A single Soviet-made P-5 configured as a class C radio frequency generator withstood 500 to 800 Volts plate voltage, and could deliver up to 1 W into the antenna, while a class A circuit could only deliver 40 mW. Audio frequency amplification in class A was feasible using arrays of parallel-connected TMs. Lifetime of a genuine French-made TM, built in strict compliance with the design, did not exceed 100 hours. During the war, factories inevitably had to use substandard raw materials which resulted in substandard tubes. These were usually marked with a cross and suffered from unusually high noise levels and random early failures due to cracks in their glass envelopes.


Production history

In the course of World War I the TM became the tube of choice of allied armies. Demand exceeded capacity of the Lyon plant, so additional production was delegated to
La Compagnie des Lampes La Compagnie des Lampes ("The Lamp Company") was a name used by several French companies all in the area of electrical products particularly lighting. La Compagnie des Lampes (1888) The original ''Compagnie des Lampes'' was set up at Ivry-sur-Se ...
plant in
Ivry-sur-Seine Ivry-sur-Seine () is a commune in the Val-de-Marne department in the southeastern suburbs of Paris, France. It is located from the centre of Paris. Paris's main Asian district, the Quartier Asiatique in the 13th arrondissement, borders the co ...
. Total production volume is unknown, but it was certainly very high for the period. Estimates of daily wartime production vary from one thousand units (Lyon plant alone) to six thousand units. Estimates of total wartime production vary from 1.1 million units (0.8 million in Lyon and 0.3 million in Ivry-sur-Seine) to 1.8 million units for the Lyon plant alone. British authorities quickly realized the benefits of the TM over domestic designs. In 1916
British Thomson-Houston British Thomson-Houston (BTH) was a British engineering and heavy industrial company, based at Rugby, Warwickshire, England, and founded as a subsidiary of the General Electric Company (GE) of Schenectady, New York, United States. They were kno ...
developed necessary technology and tooling, and Osram-Robertson (which would later merge into
Marconi-Osram Valve M-OV (Marconi-Osram Valve Company) was a British manufacturer of thermionic valves (vacuum tubes). It was a subsidiary of the (British) General Electric Company Ltd. The company was founded in 1919, when the valve making interests of GEC (Osram ...
) began large-scale production. The British variants became known collectively as ''type R''. In 1916-1917 the Osram plant produced two visually identical triode types: "hard" (high vacuum) R1, almost exactly copying the French original, and "soft"
nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...
-filled R2. The R2 was the last in the line of British gas-filled tubes; all subsequent designs from R3 to R7 were high vacuum tubes. Variants of Type R triodes were made to British order in the United States by Moorhead Laboratories. After the war,
Philips Koninklijke Philips N.V. (), commonly shortened to Philips, is a Dutch multinational conglomerate corporation that was founded in Eindhoven in 1891. Since 1997, it has been mostly headquartered in Amsterdam, though the Benelux headquarters i ...
launched production of the TM in the
Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...
as Type E. Cylindrical construction patented by Peri and Biguet became a standard feature of British high-power tubes, all the way to the 800-Watt T7X. When the United States entered the war, annual output of the three largest American manufacturers could barely reach 80 thousand tubes of all types. This was too low for a fighting army; soon after deployment in France
American Expeditionary Forces The American Expeditionary Forces (A. E. F.) was a formation of the United States Army on the Western Front of World War I. The A. E. F. was established on July 5, 1917, in France under the command of General John J. Pershing. It fought alon ...
outran the quota and had to adopt French radio equipment. Thus, the AEF relied primarily on French-made tubes. In
Russia Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...
,
Mikhail Bonch-Bruevich Mikhail Dmitriyevich Bonch-Bruyevich (russian: Михаи́л Дми́триевич Бонч-Бруе́вич;  – 3 August 1956) was an Imperial Russian and Soviet Union, Soviet military commander (Lieutenant General from 1944). His famil ...
launched small-scale production of the TM in 1917. In 1923 Soviet authorities purchased French technology and tooling, and launched large-scale production at the Leningrad Electro-Vacuum Plant which would later merge into
Svetlana Svetlana () is a common Orthodox Slavic feminine given name, deriving from the East and South Slavic root ''svet'' (), meaning "light", "shining", "luminescent", "pure", "blessed", or "holy", depending upon context similar if not the same as t ...
. Soviet clones of the TM were named P-5 and П7, a high-efficiency thoriated-cathode variant was named ''Микро'' (''Micro''). After World War I the general-purpose TM was gradually supplanted with new, specialized receiving and amplifying tubes. In the developed countries of the West the change was largely completed by the end of the 1920s, at which point it had started in less developed countries like the
Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national ...
. There is no certain information on the end of production; according to Robert Champeix, production in France probably continued until 1935. In the late 20th century, replicas of the TM were released at least twice, by Rudiger Waltz in
Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...
(1980s) and by Ricardo Kron in
Czech Republic The Czech Republic, or simply Czechia, is a landlocked country in Central Europe. Historically known as Bohemia, it is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the southeast. The ...
(1992).


References


Sources

* (Based on Champeix paper) * * (Based on Champeix paper) * {{ cite journal , last=Vyse , first=B. , title=Marconi Osram Valve. Extracts from 'The Saga of Marconi Osram Valves' , journal=British Vintage Wireless Society Magazine , date=1999 , issue=4 , url=http://www.bvws.org.uk/publications/bulletins.php/volume24number4 , pages=12–20 , language=English Vacuum tubes French inventions 1915 in France 1915 in technology 1915 in radio History of radio