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	Audion tube - Wikipedia, the free encyclopedia
		The Audion is an electronic amplifier device invented by Lee De Forest in 1906, the forerunner of what is generally known as a triode today, in which the flow of current from the filament to the plate was controlled by a third element, the grid.
		The problem was that (possibly to distance his invention from the Fleming Diode) De Forest's original patents specified that low-pressure gas inside the Audion was essential to its operation (Audion being a contraction of "Audio-Ion"), and in fact early Audions had severe reliability problems due to this gas being absorbed by the metal electrodes.
		Prior to the introduction of the Audion radio receivers had used a variety of detectors including coherers, barretters, and crystal detectors The most popular crystal detector consisted of a small piece of galena crystal probed by a fine wire commonly referred to as a "cat's whisker".
	en.wikipedia.org /wiki/Audion_tube (1399 words)

	Audion tube (Site not responding. Last check: 2007-10-22)
		The Audion is a vacuum tube device invented by Lee De Forest in 1906.
		The Audion is a three-element tube, generally known as a triode today, in which the flow of current from the filament to the plate was controlled by a third element, the grid.
		By the 1920s such "tube radios" were a fixture of most western households, and remained so until the introduction of the transistor in the 1950s.
	bopedia.com /en/wikipedia/a/au/audion_tube.html (311 words)

	De Forest Audion Tube- Paving the Way for Radio in 1906
		Lee De Forest invented the Audion vacuum tube in 1906, which went on to become the most significant electronics innovation of the first half of the 20th century after its application to radio was understood and perfected.
		This tube was called the Fleming Valve and its ability to rectify AC current was used in the Diode tubes that followed (and the same concept applies to silicon diodes today).
		The Audion became know as the Triode and was the standard means of amplification until it was gradually replaced by the transistor in the 1950's and 60's.
	www.cedmagic.com /history/deforest-audion.html (381 words)

	Audion - Wikipedia, the free encyclopedia
		the Audion tube, a wireless signal detector device invented by Lee De Forest in 1906.
		Audion (band), an indie rock band from Columbus, Ohio.
		Audion, an alias used by techno music artist Matthew Dear.
	en.wikipedia.org /wiki/Audion (115 words)

	Encyclopedia :: encyclopedia : Lee De Forest (Site not responding. Last check: 2007-10-22)
		De Forest was interested in wireless telegraphy which led to his invention of the Audion tube, in 1906, and he developed an improved wireless telegraph receiver.
		His Audion tube was a vacuum tube which allowed for amplification for radio reception.
		The resulting triode or three-electrode vacuum tube could be used as an amplifier for electrical signals, and, equally important, as a fast (for its time) electronic switching element, later applicable in digital electronics (such as computers).
	www.hallencyclopedia.com /Lee_De_Forest (1117 words)

	VACUUM TUBE RADIO
		Although tube equipment could be used for voice transmission, Morse code was more reliable for long-distance signals and continued to be the standard for marine communications.
		His tube, which he called the "audion," was first developed as a detector of radio waves and was quickly adopted by shipboard operators.
		Using the vacuum tube technology of the late 1930s, the 4-Us were large and heavy, but were suitable for mass-production under wartime conditions and proved reliable through adverse weather and enemy action.
	www.nps.gov /safr/vrtour/vrmovies/muvr2hs11.htm (778 words)

	[No title]
		The matter of who built the first vacuum tube is in considerable international dispute.
		The white rod in the center is the cathode and the two dark objects are the two plates.
		First of all neither element in the tube is a grid.
	www.angelfire.com /electronic/funwithtubes/Build_an_Audion.html (2082 words)

	Lessons In Electric Circuits -- Volume III (Semiconductors) - Chapter 13 (Site not responding. Last check: 2007-10-22)
		The semiconductor counterpart to the tube, of course, is the transistor.
		Transistors perform much the same function as tubes: controlling the flow of electrons in a circuit by means of another flow of electrons in the case of the bipolar transistor, and controlling the flow of electrons by means of a voltage in the case of the field-effect transistor.
		This same tube was sometimes used in a different way: by applying a DC voltage to one of the control grids, the gain of the tube could be changed for a signal impressed on the other control grid.
	www.faqs.org /docs/electric/Semi/SEMI_13.html (7356 words)

	The Audion Silver Night PX-25 Stereo Power Amplifier by Dick Olsher
		Furthermore, I was informed by Audion that when they originally purchased the PX-25 from England they were supplied in Golden Dragon boxes and that they were lead to believe that the tubes were of Chinese origin.
		Audion corroborated Kron's allegations and stated that they have recently found out that the tubes were manufactured by KR and were re-branded in the UK under PM Components' "Golden Dragon" brand.
		DC filament supplies are used to light up the filaments of the PX-25 output tubes, which are cathode-biased to minimize the effects of tube aging and to ensure soft clipping characteristics.
	www.enjoythemusic.com /magazine/equipment/0602/audion.htm (2051 words)

	10. Audion and Vacuum-tube Receiver Development (1907-1916)
		The inefficient design of the original Audion meant it was initially of little value to radio, and due to its high cost and short life it was rarely used.
		But as late as 1916 the Audion vacuum-tubes produced by the DeForest company were still plagued by quality control problems, and the company supplied usage tips, such as the March, 1916 QST magazine's Practical Pointers on the Audion by A. Cole, which actually revealed how little they understood about the operation of the device.
		And even after this initial, and expensive, purchase, replacement Audion tubes could only be obtained by exchanging the remnants of a burned-out Audion, as explained in the Renewal Audion Bulbs section of the catalog.
	earlyradiohistory.us /sec010.htm (734 words)

	Audion Sterling [English]
		As always there is a downside and with tubes it is often manifest in a loss of power, at least relative to the majority of the solid state offerings of today.
		Audion made their name in the high end some years back with a lovely 300B mono amp called the Silver Night.
		In the heart of its power band the Audion is a fine performer, particularly well suited to music which relies on a sense of acoustic space and instrumental timbre.
	www.tnt-audio.com /ampli/audionsterling_e.html (1451 words)

	Adventures in CyberSound: De Forest, Lee
		It was a thermionic grid-triode vacuum tube, a three-element electronic "valve" similar to a two-element device patented by the Englishman Sir John Ambrose Fleming in 1905.
		He fed the output from the plate of one tube, through a transformer to the grid of a second, and the output of the second tube's plate to the grid of a third, and so forth, thereby allowing for an enormous amplification of a signal that was originally very weak.
		In 1906, De Forest invented the triode or "audion tube", a vacuum or electron tube with 3 electrodes (instead of the 2 electrodes of the previously ubiquitous vacuum diode).
	www.acmi.net.au /AIC/DE_FOREST_BIO.html (2159 words)

	Lessons In Electric Circuits -- Volume III (Semiconductors) - ELECTRON TUBES - Andamooka Reader (Site not responding. Last check: 2007-10-22)
		De Forest's Audion tube came to be known as the triode tube, because it had three elements: filament, grid, and plate (just as the "di" in the name diode refers to two elements, filament and plate).
		Of course, it would have been quite impossible to lump thousands of tube elements into a single tube envelope the way that thousands of transistors can be etched onto a single piece of silicon, but engineers still did their best to push the limits of tube miniaturization and consolidation.
		The simplest type of ionization device is not necessarily a tube at all; rather, it is constructed of two electrodes separated by an gas-filled gap.
	www.andamooka.org /reader.pl?pgid=liecSemiSEMI_13 (4089 words)

	Empire of the Air . Glossary \| PBS
		"Audion" was the name Lee de Forest gave to his greatest invention, the radio tube.
		Invented by Howard Armstrong, the regeneration circuit fed the radio waves back through the Audion tube as many as 20,000 times a second, each time increasing its strength.
		When he fed the radio waves back through the Audion tube more than 20,000 times a second, Armstrong found that the tube began to produce its own signal, enabling de Forest's Audion to become a transmitter.
	www.pbs.org /kenburns/empire/glossary (229 words)

	Audion ETPP Monoblocks and Premier 2 phono pre
		True the Audions were twice the price, but it was not the result I expected from a valve amp.
		It's always embarrassing when you sing the wrong lyrics to a song, and I found myself being caught out again and again by the Audions where I sang what I though were the right words to a song which the Audions plainly picked out as something different.
		Yes Audion make power amps that cost five times as much, but I'm just content with these, from now on my money is going on records and after all, that is the point of the whole exercise.
	www.tnt-audio.com /ampli/audion_e.html (1353 words)

	De Forest (Site not responding. Last check: 2007-10-22)
		He is most known for his pioneering work with the vacuum tube, first as a detector of radio waves, then as an amplifier for long distance telephone calls, and finally as the major technology of the radio transmitter, still in use today.
		It was a thermionic grid-triode vacuum tube — a three-element electronic "valve" similar to a two-element device patented by Sir John Ambrose Fleming in 1905.
		The Audion was used as a detector of radio signals, an amplifier of audio and an oscillator for transmitting.
	chem.ch.huji.ac.il /~eugeniik/history/deforest.htm (3737 words)

	DeForest CF-185 Tube (Site not responding. Last check: 2007-10-22)
		Later tubes used the 4-pin Army Signal Corps base, which became known as the UV base in the early 1920's.
		Much of the early DeForest equipment was originally designed to use the screw-base spherical Audion tube.
		Though the construction was far more sophisticated than that of the Audion, the roughness visible in the plates is proof that DeForest was still building his tubes almost entirely by hand.
	uv201.com /Tube_Pages/deforest_cf185.htm (212 words)

	Stephen Greene's essay on Lee deForest
		Years later, this Audion Tube was to be called one of the world’s 20 great inventions (Dunlap, 1944).
		The first attacked General Electric’s claims that its introduction of a superior vacuum tube for de Forest’s original Audion Tube constituted a new invention and thus was patentable for an additional period of time.
		The July 4, 1961, editorial said the Audion Tube was “one of the greatest single inventions of this or any other century” and made possible “satellites, interplanetary travel, the age of automation, computing machines.” (Quoted in Editorial, 1961).
	geocities.com /lyon95065/Radio.html (6410 words)

	SoundStage! Equipment Review -Audion Sterling ETSE EL34 Integrated Amplifier (10/2002)
		Audion suggests that the output tubes should provide a minimum of 2000 hours of life or approximately two years in general use.
		Audion warns that the heat produced is equivalent to that of a 25W-50W light bulb and prescribes against the tubes being touched -- good advice with any tube amp.
		The Audion integrated had no problem reproducing the acoustic bass on "Don’t Mean A Thing" with lots of woody tonality as well as power.
	www.soundstage.com /revequip/audion_sterling.htm (2658 words)

	AUDION - Condensatori Jensen
		The capacitor element is insulated from the tube.
		The terminal which is contacted the outer foil (the foil which is the closest to the can) is always marked with an vertical line on the marking.
		Our philosophy is ultimate performance and as a consequence of manufacturing high quality capacitors for the primary signal path we have also developed a range of electrolytic capacitors mainly for use in power supply of solid state and tube high end audio equipment.
	www.audion.net /ita/htm_ita/condensatori.htm (741 words)

	☞ vacuum - three element vacuum tube - three element vacuum tube online guide
		his audion tube), De Forest held more than 300 patents but is most remembered for initiating the electronic revolution with his 1906 invention of the audion tube, a three-element vacuum tube...
		This was the first advance in function since de Forest's Audion, built on the findings of the Fleming diode (two-element) valve, introduced the triode (three-element) vacuum tube.
		Forest invents the audion tube, a three-element vacuum tube in which the grid...
	www.all-vacuum.info /vacuumtube/three-element-vacuum-tube.html (670 words)

	Lee De Forest
		Lee De Forest invented the audion, a vacuum tube device that could take a weak electrical signal and amplify it into a larger one.
		The audion helped ATandT set up coast-to-coast phone service, and it was also used in everything from radios to televisions to the first computers.
		The audion, or triode, at the heart of the vacuum tube is what the transistor was built to replace.
	www.pbs.org /transistor/album1/addlbios/deforest.html (396 words)

	DeForest Spherical Audion
		In 1906, Lee DeForest added the grid element to the Fleming Valve and created the triode vacuum tube, which he called the "Audion".
		The earliest Audions had a single grid and plate (single wing); later ones had two grids and plates (double wing).
		As important as this invention was, it was not until the technology was licensed to major corporations (most notably Western Electric) that the Audion was developed into a truly practical device.
	uv201.com /Tube_Pages/deforest_audion.htm (231 words)

	EH.Net Encyclopedia: History of the Radio Industry in the United States to 1940
		In 1912 he was indicted for using the mails to defraud by promoting "a worthless device," the Audion tube.
		The Audion tube (later known as a triode tube) was far from being a worthless device, as it was a key component of radios so long as vacuum tubes continued to be used.
		(The vacuum tube's obsolescence was the result of a study of semiconductors in 1948 by William Shockley, Walter Brattain, and John Bardeen.
	www.eh.net /encyclopedia/article/scott.radio.industry.history (3977 words)

	History of Communications - RADIO: The Quality that Made Radio Popular
		Although it was the late 1920's before vacuum tube shortwave transmitters began to replace Alexanderson's mighty alternators, exploratory work using vacuum tubes as amplifiers in radio receiving equipment began around 1900.
		He was 16 when DeForest announced his Audion tube and one of these fragile, expensive tubes was added to his study equipment.
		In 1912, as a junior at Columbia University he continued his interest in radio and the Audion tube by inventing a regenerative circuit that fed part of the current back to the grid in the tube.
	www.fcc.gov /omd/history/radio/quality.html (1061 words)

	Lee de Forest Invented the Radio Tube
		The first use of the audion was as a detector of radio waves.
		While there, de Forest finally made his Audion tube perform as an amplifier and sold it to the telephone company as an amplifier of transcontinental wired phone calls.
		By 1916, he had perfected his Audion for its most important task, that of an oscillator for the radiotelephone transmitter.
	www.leedeforest.org /inventor.html (278 words)

	Vacuum Tubes
		he Edison effect, the appearance of an electric current flowing between a heated cathode and an anode in an evacuated tube, was a mysterious phenomenon when it was discovered in 1882; it was not understood how electric current could pass through a vacuum.
		Thomson's identification of cathode rays as streams of electrons resolved the mystery and led to the invention of the thermionic diode by Fleming.
		His discoveries about the emission of electrons from cathodes and their behavior in vacuum tubes formed the basis for the design of a variety of tube types.
	www.ee.umd.edu /~taylor/Electrons3.htm (639 words)

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