TM (triode)

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TM triode. Drawing from the 1915 Peri and Biguet patent Loupiote radio 1915.jpg
TM triode. Drawing from the 1915 Peri and Biguet patent

The TM (from French : Telegraphie Militaire, also marketed as TM Fotos and TM Metal) was a triode vacuum tube for amplification and demodulation of radio signals, manufactured in France from November 1915 to around 1935. The TM, developed for the French Army, became the standard small-signal radio tube of the Allies of World War I, and the first truly mass-produced vacuum tube. [1] [2] Wartime production in France is estimated at no less than 1.1 million units. [3] Copies and derivatives of the TM were mass-produced in the United Kingdom as Type R, in the Netherlands as Type E, in the United States and in Soviet Russia as P-5 and П7.

Contents

Development

Development of the TM was initiated by colonel Gustave-Auguste Ferrié, chief of French long-distance military communications (Télégraphie Militaire). [4] [5] Ferrié and his closest associate Henri Abraham were well informed about American research in radio and vacuum technology. [6] [7] They knew that Lee de Forest's audion and the British gas-filled lamp designed by H. J. Round were too unstable and unreliable for military service, and that Irving Langmuir's pliotron was too complex and expensive for mass production. [6]

Shortly after the outbreak of World War I, a former Telefunken 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. [8] [9] [10] The problems were traced to insufficiently hard vacuum. [8] [7] Following suggestions made by Langmuire, Ferrié made a strategically correct decision to refine industrial vacuum pump technology that could guarantee sufficiently hard vacuum in mass production. The future French triode needed to be reliable, reproducible and inexpensive. [10]

In October 1914 Ferrié dispatched Abraham and Michel Peri to Grammont incandescent lamp plant in Lyon. [11] [9] Abraham and Peri started with copying American designs. [12] [9] As was expected, the audion was unreliable and unstable, the pliotron and the first three original French prototypes were too complex. [12] [9] 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. [13] [9] This triode, known as the Abraham tube, did not pass the test of field service: many tubes were damaged during transportation. [14] [9]

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 (the original Abraham tube used an Edison screw with two additional flexible wires). [14] [9] In November 1915 the new triode was pressed into production and became known as the TM after the French service that developed it. [15] [9] Work by Ferrié and Abraham was nominated for the 1916 Nobel Prize in Physics. [16] However, the patent was granted solely to Peri and Biguet, causing future legal disputes. [17] [18]

Design and specifications

Anode (cylinder), grid (coil) and cathode filament (thin wire inside coil). British Type R tube 2015-03-07 - Thinktank - Sasha Taylor - 74.JPG
Anode (cylinder), grid (coil) and cathode filament (thin wire inside coil). British Type R tube

The electrode assembly of the TM has nearly perfect cylindrical shape. The anode is a nickel cylinder, 10 mm in diameter and 15 mm long. [19] [20] Grid diameter varies from 4.0 to 4.5 mm; the Lyon plant made grids of pure molybdenum, the plant in Ivry-sur-Seine used nickel. The directly-heated cathode filament is a straight wire of pure tungsten, 0.06 mm in diameter. [19] [21]

Pure tungsten cathode reached proper emission level when heated to white incandescence, which required heating current of over 0.7 A at 4 V. [19] [21] The filament was so bright that in 1923 Grammont replaced clear glass envelope with dark blue cobalt glass. [19] [22] 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. [19] [22] 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. [19] [22]

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 required). [19] [21] In this mode, the tube operated at 2 mA standing anode current, and had transconductance of 0.4 mA/V, gain (μ) of 10 and anode impedance of 25 kOhm. [19] [21] 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. [19] [21] High grid currents, an inevitable consequence of primitive technology of the 1910s, simplified grid leak biasing. [21]

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. [23] 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. [23] Audio frequency amplification in class A was feasible using arrays of parallel-connected TMs. [23]

Lifetime of a genuine French-made TM, built in strict compliance with the design, did not exceed 100 hours. [21] During the war, factories inevitably had to use substandard raw materials which resulted in substandard tubes. [21] 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. [21]

Production history

Two Type R triodes in a British Aircraft Tuner Receiver Mk. III, 1917 2015-03-07 - Thinktank - Sasha Taylor - 50.JPG
Two Type R triodes in a British Aircraft Tuner Receiver Mk. III, 1917

In the course of World War I the TM became the tube of choice of allied armies. [18] Demand exceeded capacity of the Lyon plant, so additional production was delegated to La Compagnie des Lampes plant in Ivry-sur-Seine. [18] Total production volume is unknown, but it was certainly very high for the period. [24] Estimates of daily wartime production vary from one thousand units (Lyon plant alone) to six thousand units. [24] Estimates of total wartime production vary from 1.1 million units (0.8 million in Lyon and 0.3 million in Ivry-sur-Seine) [3] [18] to 1.8 million units for the Lyon plant alone. [3]

British authorities quickly realized the benefits of the TM over domestic designs. [25] In 1916 British Thomson-Houston developed necessary technology and tooling, and Osram-Robertson (which would later merge into Marconi-Osram Valve) began large-scale production. [26] The British variants became known collectively as type R. [26] 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-filled R2. [26] The R2 was the last in the line of British gas-filled tubes; all subsequent designs from R3 to R7 were high vacuum tubes. [26] Variants of Type R triodes were made to British order in the United States by Moorhead Laboratories. After the war, Philips launched production of the TM in the Netherlands as Type E. [19] Cylindrical construction patented by Peri and Biguet became a standard feature of British high-power tubes, all the way to the 800-Watt T7X. [27]

When the United States entered the war, annual output of the three largest American manufacturers could barely reach 80 thousand tubes of all types. [2] This was too low for a fighting army; soon after deployment in France American Expeditionary Forces outran the quota and had to adopt French radio equipment. [2] Thus, the AEF relied primarily on French-made tubes. [2]

In Russia, Mikhail Bonch-Bruevich launched small-scale production of the TM in 1917. [28] 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. [28] Soviet clones of the TM were named P-5 and П7, a high-efficiency thoriated-cathode variant was named Микро (Micro). [29]

After World War I the general-purpose TM was gradually supplanted with new, specialized receiving and amplifying tubes. [29] 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. [29] There is no certain information on the end of production; according to Robert Champeix, production in France probably continued until 1935. [19] In the late 20th century, replicas of the TM were released at least twice, by Rudiger Waltz in Germany (1980s) [30] and by Ricardo Kron in Czech Republic (1992). [31]

Related Research Articles

Triode

A triode is an electronic amplifying vacuum tube 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 1906 Audion, a partial vacuum tube that added a grid electrode to the thermionic diode, the triode was the first practical electronic amplifier and the ancestor of other types of vacuum tubes such as the tetrode and pentode. Its invention founded the electronics age, making possible amplified radio technology and long-distance telephony. Triodes were widely used in consumer electronics devices such as radios and televisions until the 1970s, when transistors replaced them. Today, their main remaining use is in high-power RF amplifiers in radio transmitters and industrial RF heating devices. In recent years there has been a resurgence in demand for low power triodes due to renewed interest in tube-type audio systems by audiophiles who prefer the sound of tube-based electronics.

Vacuum tube Device that controls electric current between electrodes in an evacuated container

A vacuum tube, an electron tube, valve or tube, is a device that controls electric current flow in a high vacuum between electrodes to which an electric potential difference has been applied.

A tetrode is a vacuum tube having four active electrodes. The four electrodes in order from the centre are: a thermionic cathode, first and second grids and a plate. There are several varieties of tetrodes, the most common being the screen-grid tube and the beam tetrode. In screen-grid tubes and beam tetrodes, the first grid is the control grid and the second grid is the screen grid. In other tetrodes one of the grids is a control grid, while the other may have a variety of functions.

Thyratron Gas filled tube, electrical switch, rectifier

A thyratron is a type of gas-filled tube used as a high-power electrical switch and controlled rectifier. Thyratrons can handle much greater currents than similar hard-vacuum tubes. Electron multiplication occurs when the gas becomes ionized, producing a phenomenon known as Townsend discharge. Gases used include mercury vapor, xenon, neon, and hydrogen. Unlike a vacuum tube (valve), a thyratron cannot be used to amplify signals linearly.

Pentagrid converter

The pentagrid converter is a type of radio receiving valve with five grids used as the frequency mixer stage of a superheterodyne radio receiver.

Control grid

The control grid is an electrode used in amplifying thermionic valves such as the triode, tetrode and pentode, used to control the flow of electrons from the cathode to the anode (plate) electrode. The control grid usually consists of a cylindrical screen or helix of fine wire surrounding the cathode, and is surrounded in turn by the anode. The control grid was invented by Lee De Forest, who in 1906 added a grid to the Fleming valve to create the first amplifying vacuum tube, the Audion (triode).

KT66

KT66 is the designator for a beam tetrode vacuum tube introduced by Marconi-Osram Valve Co. Ltd. (M-OV) of Britain in 1937.

6L6

6L6 is the designator for a vacuum tube introduced by Radio Corporation of America in July 1936. At the time Philips had already developed and patented power pentode designs, which were rapidly replacing power triodes due to their greater efficiency. The beam tetrode design of the 6L6 allowed RCA to circumvent Philips' pentode patent.

Beam tetrode

A beam tetrode, sometimes called a "beam power tube", is a type of tetrode vacuum tube with auxiliary beam-focusing plates designed to augment power-handling capability and help reduce unwanted emission effects. These tubes are usually used for power amplification, especially at audio-frequency.

Pentode

A pentode is an electronic device having five active electrodes. The term most commonly applies to a three-grid amplifying vacuum tube, which was invented by Gilles Holst and Bernhard D.H. Tellegen in 1926. The pentode consists of an evacuated glass envelope containing five electrodes in this order: a filament for indirectly heating a cathode, a control grid, a screen grid, a suppressor grid, and a plate (anode). The pentode was developed from the tetrode tube by the addition of a third grid, the suppressor grid. This served to prevent secondary emission electrons emitted by the plate from reaching the screen grid, which caused instability and parasitic oscillations in the tetrode. The pentode is closely related to the beam tetrode. Pentodes were widely used in industrial and consumer electronic equipment such as radios and televisions until the 1960s, when they were replaced by transistors. Their main use now is in high power industrial applications such as radio transmitters. The obsolete consumer tubes are still used in a few legacy and specialty vacuum tube audio devices.

In Europe, the principal method of numbering vacuum tubes was the nomenclature used by the Philips company and its subsidiaries Mullard in the UK, Valvo(de, it) in Germany, Radiotechnique (Miniwatt-Dario brand) in France, and Amperex in the United States, from 1934 on. Adhering manufacturers include AEG (de), CdL (1921, French Mazda brand), CIFTE (fr, Mazda-Belvu brand), EdiSwan (British Mazda brand), Lorenz (de), MBLE(fr, nl), RCA (us), RFT(de, sv) (de), Siemens (de), Telefunken (de), Tesla (cz), Toshiba (ja), Tungsram (hu), and Unitra. This system allocated meaningful codes to tubes based on their function and became the starting point for the Pro Electron naming scheme for active devices.

Battery (vacuum tube)

In the early days of electronics, vacuum tube devices were powered by batteries. Each battery had a different designation depending on which vacuum tube element it was associated with.

The KT88 is a beam tetrode/kinkless tetrode vacuum tube for audio amplification.

Fleming valve

The Fleming valve, also called the Fleming oscillation valve, was a thermionic valve or vacuum tube invented in 1904 by English physicist John Ambrose Fleming as a detector for early radio receivers used in electromagnetic wireless telegraphy. It was the first practical vacuum tube and the first thermionic diode, a vacuum tube whose purpose is to conduct current in one direction and block current flowing in the opposite direction. The thermionic diode was later widely used as a rectifier — a device which converts alternating current (AC) into direct current (DC) — in the power supplies of a wide range of electronic devices, until beginning to be replaced by the selenium rectifier in the early 1930s and almost completely replaced by the semiconductor diode in the 1960s. The Fleming valve was the forerunner of all vacuum tubes, which dominated electronics for 50 years. The IEEE has described it as "one of the most important developments in the history of electronics", and it is on the List of IEEE Milestones for electrical engineering.

Magic eye tube

A magic eye tube or tuning indicator, in technical literature called an electron-ray indicator tube, is a vacuum tube which gives a visual indication of the amplitude of an electronic signal, such as an audio output, radio-frequency signal strength, or other functions. The magic eye is a specific type of such a tube with a circular display similar to the EM34 illustrated. Its first broad application was as a tuning indicator in radio receivers, to give an indication of the relative strength of the received radio signal, to show when a radio station was properly tuned in.

Acorn tube Family of VHF/UHF vacuum tubes

An acorn tube, or acorn valve, refers to any member of a family of VHF/UHF vacuum tubes starting just before World War II. They were named after their resemblance to the acorn, specifically due to the glass cap at one end of the tube that looked similar to the cap on an acorn. The acorn tubes found widespread use in radios and radar systems.

M-OV was a British manufacturer of thermionic valves. It was a subsidiary of the (British) General Electric Company Ltd.

La Compagnie des Lampes was a name used by several French companies all in the area of electrical products particularly lighting.

In electronics, a micropup is a style of triode vacuum tube (valve) developed during World War II for use at very high frequencies such as those used in radar. They are characterized by an external anode block, which allows better heat dissipation. These tubes could deliver radio frequency power on the order of kilowatts at wavelengths as short as 25 cm., and on the order of 100 kW at 200 MHz in pulses. Micropup tubes used very high voltages to minimize the transit time of electrons between anode and cathode.

References

  1. ↑ Vyse 1999, pp. 17, 18.
  2. 1 2 3 4 Flichy, P. (1999). "The Wireless Age: Radio Broadcasting". The Media Reader: Continuity and Transformation. Sage. p. 83. ISBN   9780761962502.
  3. 1 2 3 Champeix 1980, pp. 23, 24.
  4. ↑ Berghen 2002, p. 20.
  5. ↑ Champeix 1980, p. 5.
  6. 1 2 Champeix 1980, p. 9.
  7. 1 2 Berghen 2002, pp. 20, 21.
  8. 1 2 Champeix 1980, p. 11.
  9. 1 2 3 4 5 6 7 8 Berghen 2002, p. 21.
  10. 1 2 Ginoux 2017, p. 41.
  11. ↑ Champeix 1980, p. 12.
  12. 1 2 Champeix 1980, p. 14.
  13. ↑ Champeix 1980, p. 15.
  14. 1 2 Champeix 1980, p. 16.
  15. ↑ Champeix 1980, p. 19.
  16. ↑ Crawford, E. (2002). The Nobel Population 1901-1950: A Census of the Nominators and Nominees for the Prizes in Physics and Chemistry. pp. 345, 365. ISBN   9784946443701.
  17. ↑ Champeix 1980, pp. 19–21.
  18. 1 2 3 4 Berghen 2002, p. 22.
  19. 1 2 3 4 5 6 7 8 9 10 11 Berghen 2002, p. 23.
  20. ↑ Champeix 1980, p. 25.
  21. 1 2 3 4 5 6 7 8 9 Champeix 1980, p. 26.
  22. 1 2 3 Champeix 1980, p. 27.
  23. 1 2 3 Марк 1929, p. 186.
  24. 1 2 Champeix 1980, p. 23.
  25. ↑ Vyse 1999, p. 17.
  26. 1 2 3 4 Vyse 1999, p. 18.
  27. ↑ Vyse 1999, p. 19.
  28. 1 2 Bazhenov, V. I. (1923). "Русская радиотехника". Успехи физических наук (2): 17.
  29. 1 2 3 Марк, М. Г. (1929). "Наши лампы". Радиолюбитель (in Russian) (5): 183–188.
  30. ↑ Walz, R. "Home-made Electron Tube Replica" (PDF). Archived from the original (PDF) on 2019-03-03. Retrieved 2017-08-02.
  31. ↑ "Marconi R Valve". KR Audio. Archived from the original on 2017-08-02. Retrieved 2017-08-02.

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