335:). The negative electrons emitted from the cathode are accelerated toward the positive grid. Most pass between the grid wires and continue toward the anode plate, but the negative potential on the anode repels them and they reverse direction before they hit the surface of the anode plate and are accelerated back toward the relatively higher potential grid through which they have just passed. Again, most pass through the grid wires, but they are then repelled by the negative potential of the cathode and reverse direction just before reaching the surface of the cathode. The electrons continue oscillating back and forth through the grid until one by one they strike the grid wires.
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The success of the
Barkhausen-Kurz tube in generating radio waves at microwave frequencies inspired research to develop similar tubes which did not have its power limitations, resulting in the invention of other tubes which were known as "reflex oscillators". The best known result of this research
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The oscillatory motion of the electron cloud continues; this cloud constitutes the alternating output current. Some electrons are lost to the grid on each pass, but the electron supply is continually replenished by new electrons emitted by the cathode. Compared to a conventional triode oscillator,
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region, the first vacuum tube to do so. Although severely limited in output power, the
Barkhausen–Kurz tube was quickly adopted world-wide for UHF research. This device is also called the retarded-field and positive-grid oscillator. Versions of the Barkhausen oscillator were used in some of the
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the number of electrons actually hitting the anode plate and grid is small, so the plate and grid alternating currents are small, and the output power of the B-K oscillator is low. Higher power devices like the klystron were later developed to overcome this limitation.
212:, above 300 MHz. It was also the first oscillator to exploit electron transit time effects. It was used as a source of high frequency radio waves in research laboratories, and in a few UHF
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system, a 1.7 GHz link 40 miles across the
English channel in 1931, used a Barkhausen-Kurz tube mounted at the focus of the 10 foot dish shown. It had a radiated power of about 1/2 watt.
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at which the triode could be used was limited by the spacing between internal components. Even with the smallest of spacing, the frequency limit of early triodes was in the low
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through World War 2. Its output power was low which limited its applications. However it inspired research that led to other more successful transit time tubes such as the
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The frequency of oscillation depends on the spacing and potentials of the electrodes, and can be tuned within a limited bandwidth by altering the electrode voltages.
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tube invented 1937 by
Russell and Sigurd Varian, which is widely used as a high power source of microwaves to the present. Sources like the klystron and
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in 1906 was the first device that could amplify, and was used in most radio transmitters and receivers from 1920 on. It was found that the highest
262:, Germany used the velocity modulation theory in developing a "retarded-field" triode. They found it could operate at frequencies into the
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Experimental low power 3 GHz AM communication link from 1938 uses
Barkhausen-Kurz tubes for both transmitting and receiving
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The oscillating grid potential induced by the passage of the electrons through the grid excites oscillations in a
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Historical German contributions to physics and applications of electromagnetic oscillations and waves
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range. A technique called velocity modulation was theorized to overcome this limitation.
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400:. Electron Device Society, Institute of Electrical and Electronics Engineers (IEEE)
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and Karl Kurz. It was the first oscillator that could produce radio power in the
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Alfvén, Hannes, “On the theory of the
Barkhausen-Kurz oscillations,”
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An experimental push-pull
Barkhausen oscillator in 1933, which uses
319:(a thin mesh of wires) at a positive potential relative to both the
538:"Investigations in the field of ultra-short electromagnetic waves"
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into a cloud of electrons moving back and forth through the grid
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replaced the B-K tube around World War 2 and it became obsolete.
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first applications of microwaves, such as the first experimental
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220:, which made the low power Barkhausen-Kurz tube obsolete.
391:"Heinrich Barkhausen: First transit-time microwave tube"
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attached to the grid, usually consisting of a quarter
479:Faragő, P. S., and G. Groma, "Reflex oscillators",
46:. Unsourced material may be challenged and removed.
461:(2). New York: Radio Science Publications: 107–109
494:Applications of Microwaves in Scientific Research
158:. It could generate 5 watts at 400 MHz.
509:Series 7, Vol. 19, February, 1935, pp. 419–422
481:Acta physica Academiae Scientiarum Hungaricae
448:"Searchlight radio with the new 7 inch waves"
8:
106:Learn how and when to remove this message
483:, Vol. 4, No. 1, August, 1954, pp. 7–22
384:
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200:invented in 1920 by German physicists
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44:adding citations to reliable sources
422:Fiber Optics Illustrated Dictionary
271:system, a 1.7 GHz link across the
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311:The Barkhausen–Kurz tube was a
31:needs additional citations for
279:systems used in World War 2.
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362:at the resonant frequency.
350:shorted at the end, called a
536:Potapenko, G. (1932-02-13).
147:(quarter-wave parallel wire
446:Free, E. E. (August 1931).
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425:. CRC Press. p. 103.
202:Heinrich Georg Barkhausen
492:Klinger, Hans Herbert,
419:Petersen, J.K. (2002).
389:Thumm, Manfred (2011).
303:The first experimental
557:10.1103/PhysRev.39.625
507:Philosophical Magazine
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275:in 1931, and in early
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55:"Barkhausen–Kurz tube"
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256:Technische Hochschule
254:and Karl Kurz at the
208:(UHF) portion of the
198:electronic oscillator
193:was a high frequency
191:Barkhausen oscillator
175:Barkhausen–Kurz tube,
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532:at Wikimedia Commons
530:Barkhausen–Kurz tube
206:ultra-high frequency
179:retarding-field tube
40:improve this article
252:Heinrich Barkhausen
315:operated with the
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214:radio transmitters
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580:German inventions
528:Media related to
348:transmission line
149:transmission line
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96:December 2009
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29:This article
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575:Vacuum tubes
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463:. Retrieved
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346:of parallel
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295:How it works
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156:tank circuit
145:Lecher lines
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38:Please help
33:verification
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551:: 625–638.
233:vacuum tube
195:vacuum tube
569:Categories
455:Radio News
432:084931349X
373:References
344:wavelength
327:) and the
66:newspapers
465:March 24,
404:March 30,
250:In 1920,
245:megahertz
241:frequency
154:) as the
545:Phys Rev
360:in phase
325:filament
285:klystron
283:was the
218:klystron
321:cathode
260:Dresden
224:History
80:scholar
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313:triode
230:triode
189:, and
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541:(PDF)
451:(PDF)
394:(PDF)
356:bunch
333:plate
329:anode
277:radar
152:stubs
87:JSTOR
73:books
467:2015
427:ISBN
406:2013
331:(or
323:(or
317:grid
228:The
173:The
59:news
553:doi
264:UHF
258:in
42:by
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