Diagram of Vacuum-Tube DiodeDiagram of Vacuum-Tube TriodeInside of a vacuum tube with plate cut open.A two-tube homemade radio from 1958. The tubes are the two glass columns with the dark tops. The leads at the bottom connect to the low-voltage filament supply and to the high-voltage anode supplyAn RCA 12AX7 dual-triode tube (1947)

Discover great deals on the many top brand items available only on eBay!

Tubes

In electronics, a vacuum tube (U.S. and Canadian English) or (thermionic) valve (outside North America) is a device generally used to amplify, or otherwise modify, a signal by controlling the movement of electrons in an evacuated space. more...

HomeHome
Accessories & CablesAccessories & Cables
AmplifiersAmplifiers
CD Players & RecordersCD Players & Recorders
Cassette DecksCassette Decks
CrossoversCrossovers
DVD Players & Recorders DVD Players & Recorders
Digital Music...Digital Music...
Digital Video Recorders, PVRDigital Video Recorders, PVR
EqualizersEqualizers
Headphones, HeadsetsHeadphones, Headsets
Home Audio MiscHome Audio Misc
Home Theater ProjectorsHome Theater Projectors
Home Theater in a Box Home Theater in a Box
KaraokeKaraoke
MiniDisc PlayersMiniDisc Players
OtherOther
PreamplifiersPreamplifiers
ProcessorsProcessors
RadiosRadios
ReceiversReceivers
Remote ControlsRemote Controls
Satellite Radio Satellite Radio
Satellite, Cable TVSatellite, Cable TV
Shelf, Compact SystemsShelf, Compact Systems
Speakers & SubwoofersSpeakers & Subwoofers
Televisions TVTelevisions TV
Tuners, AM/FMTuners, AM/FM
TurntablesTurntables
VCRsVCRs
Vintage ElectronicsVintage Electronics
8-Track Players8-Track Players
Amplifiers, Tube AmpsAmplifiers, Tube Amps
Books, Manuals, MagazinesBooks, Manuals, Magazines
CapacitorsCapacitors
Cassette DecksCassette Decks
Drivers & HornsDrivers & Horns
Other VintageOther Vintage
Preamplifiers, Tube PreampsPreamplifiers, Tube Preamps
RadiosRadios
ReceiversReceivers
Reel-to-Reel Tape RecordersReel-to-Reel Tape Recorders
SpeakersSpeakers
TelephonesTelephones
TelevisionsTelevisions
TransformersTransformers
TubesTubes
NOS TubesNOS Tubes
Other TubesOther Tubes
Tube SocketsTube Sockets
Vacuum TubesVacuum Tubes
General ElectricGeneral Electric
MullardMullard
Other BrandsOther Brands
RCARCA
SylvaniaSylvania
Western ElectricWestern Electric
Tuners, Tube TunersTuners, Tube Tuners
TurntablesTurntables
Wholesale LotsWholesale Lots

Once used in most electronic devices, vacuum tubes are now used only in specialized applications. For most purposes, the vacuum tube has been replaced by the much smaller and less expensive transistor, either as a discrete device or in an integrated circuit. At the start of the 21st century there has been renewed interest in the vacuum tube, this time in the form of the Field-emitter microtube.

Operation

Vacuum tubes, or thermionic valves, are arrangements of electrodes in a vacuum within an insulating, temperature-resistant envelope. Although the envelope was classically glass, power tubes often use ceramic and metal. The electrodes were attached to leads which passed through the envelope in a way that was sealed air tight. On most tubes, the leads were designed to plug into tube sockets for easy replacement.

The simplest vacuum tubes resemble incandescent light bulbs in that they have a filament sealed in a glass envelope which has been evacuated of all air. When hot, the filament releases electrons into the vacuum: a process called thermionic emission. The resulting negatively-charged cloud of electrons is called a space charge. These electrons will be drawn to a metal plate inside the envelope if the plate (also called the anode) is positively charged relative to the filament (or cathode). This results in a current of electrons flowing from filament to plate. This cannot work in the reverse direction because the plate is not heated and cannot emit electrons. This very simple example described can thus be seen to operate as a diode: a device that conducts current only in one direction.

Development

John Ambrose Fleming, scientific adviser to the Marconi company invented the diode in 1904 based on an observation by Thomas Edison (Edison received U.S. Patent 307031 from this observation). The unidirectional current and construction of the original diode led to Lee DeForest placing another electrode, a bent wire or screen, between the filament and plate electrode in 1906. DeForest discovered that the current flow from filament to plate depended on the voltage applied to the grid, and that the current drawn by the grid was very low, being composed of the electrons which are intercepted by the grid. As the applied voltage of the grid varied from negative to positive, the current of electrons flowing from the filament to the plate would vary accordingly. Thus the grid was said to electrostatically "control" the plate current. The resulting three-electrode device was therefore an excellent and very sensitive amplifier of voltages. DeForest called his invention the audion, but it is better known as a triode. The tube equivalent of a transistor, triodes were used in early tube amplifiers.

Read more at Wikipedia.org


[List your site here Free!]

New listing
		25x In18 In-18 ИН-18 Nixie Tubes Nos New | Factory Box | Same Date Code | DiyNew listing 25x In18 In-18 ИН-18 Nixie Tubes Nos New | Factory Box | Same Date Code | Diy $1,149.00 New listing
		1P24B-V 1П24Б and 6J5B-V 6Ж5Б-В Russian Miniature Tube. Nos.New listing 1P24B-V 1П24Б and 6J5B-V 6Ж5Б-В Russian Miniature Tube. Nos. $0.99
New listing
		(2) Sylvania Electronic Tube 6Bk4C-6El4A Vacuum Tubes Brand New Nos.New listing (2) Sylvania Electronic Tube 6Bk4C-6El4A Vacuum Tubes Brand New Nos. $30.00 New listing
		6 x z570m rft germany nixie tubes. nixie tubeNew listing 6 x z570m rft germany nixie tubes. nixie tube $43.90
New listing
		2) Zenith / Delta 25L6G Antique Power Amplifier Vacuum Tube ~ Tv-7 TestedNew listing 2) Zenith / Delta 25L6G Antique Power Amplifier Vacuum Tube ~ Tv-7 Tested $12.95 New listing
		Electronic tubes E88Cc, SiemensNew listing Electronic tubes E88Cc, Siemens $1.35
New listing
		50x Ivl2-7/5 Vfd Clock Display Indicator (New, Nos, old stock)New listing 50x Ivl2-7/5 Vfd Clock Display Indicator (New, Nos, old stock) $49.99 New listing
		One Visseaux A710 tube triode Nos Nib best ever 10Y Vt25 10 type tubeNew listing One Visseaux A710 tube triode Nos Nib best ever 10Y Vt25 10 type tube $220.00
New listing
		4 Radiotron El34 vintage made in EnglandNew listing 4 Radiotron El34 vintage made in England $200.00 New listing
		6x nixie socket B13BNew listing 6x nixie socket B13B $19.90
New listing
		Sylvania Type 42 Engraved Base Vintage Usa Vacuum Tube - Amplitrex Tested 69% GmNew listing Sylvania Type 42 Engraved Base Vintage Usa Vacuum Tube - Amplitrex Tested 69% Gm $25.00 New listing
		Pair 12Bh7A International Nos Vacuum Tubes Nib 3x Mica TestedNew listing Pair 12Bh7A International Nos Vacuum Tubes Nib 3x Mica Tested $21.98
New listing
		8pcs In-18 In18 Nixie tubes Nos One party!New listing 8pcs In-18 In18 Nixie tubes Nos One party! $372.50 New listing
		Telefunken 12Ax7- Vintage TubeNew listing Telefunken 12Ax7- Vintage Tube $20.00
New listing
		12At7 (Ecc81) Vacuum Tubes - United Electron - England - 1960's ($14.95/ea)New listing 12At7 (Ecc81) Vacuum Tubes - United Electron - England - 1960's ($14.95/ea) $14.95 New listing
		2 vintage Telefunken Ecc88 in very good conditionNew listing 2 vintage Telefunken Ecc88 in very good condition $1.35
New listing
		Quad Itt Stc 12E1 tube Similar Kt88 Nos Nib Original military boxesNew listing Quad Itt Stc 12E1 tube Similar Kt88 Nos Nib Original military boxes $120.00 New listing
		Pair General Electric Vt 4C 211 year 1941New listing Pair General Electric Vt 4C 211 year 1941 $180.00
New listing
		6pc Ceramic Gold 8pin Octal Tube Socket El34 5U4G 5881 6Sn7 5Ar4 Kt88 K8A PcbNew listing 6pc Ceramic Gold 8pin Octal Tube Socket El34 5U4G 5881 6Sn7 5Ar4 Kt88 K8A Pcb $6.99 New listing
		(2) Raytheon Ck5755 Tubes. Matching. Nos.New listing (2) Raytheon Ck5755 Tubes. Matching. Nos. $30.00
New listing
		2pcs 8 Pin El34 6550 Kt88 Cmc Bakelite Gold Tube SocketNew listing 2pcs 8 Pin El34 6550 Kt88 Cmc Bakelite Gold Tube Socket $11.99 New listing
		military Tube E88Cc Tesla Special selection 2 pcsNew listing military Tube E88Cc Tesla Special selection 2 pcs $100.00
New listing
		Tung-Sol Type 47 Vintage Made in Usa Vacuum Tube - Amplitrex Tested 101% GmNew listing Tung-Sol Type 47 Vintage Made in Usa Vacuum Tube - Amplitrex Tested 101% Gm $35.00 New listing
		1piece Gold 6F8G instead Ecc88 6922 6N6 tube converter adapter socketNew listing 1piece Gold 6F8G instead Ecc88 6922 6N6 tube converter adapter socket $16.90
New listing
		Nos 12X4 (Hz90) Vacuum Tubes, Rca - Usa - 1960's Bulk Packaged ($10/ea)New listing Nos 12X4 (Hz90) Vacuum Tubes, Rca - Usa - 1960's Bulk Packaged ($10/ea) $10.00 New listing
		Tested! 5 X 6K3 / 6Sk7 Soviet Tubes Qty=5 1980`sNew listing Tested! 5 X 6K3 / 6Sk7 Soviet Tubes Qty=5 1980`s $8.00
New listing
		2 vintage Philips dual single monoplate 2A3 valves Rca copper rods 50 ux245 300bNew listing 2 vintage Philips dual single monoplate 2A3 valves Rca copper rods 50 ux245 300b $400.00 New listing
		12 X Tested 6N3P = 6Cc42=2C51=Ecc42 Doublt triod. 1984. Pcs 12.New listing 12 X Tested 6N3P = 6Cc42=2C51=Ecc42 Doublt triod. 1984. Pcs 12. $12.00
New listing
		50x 5C4S (5Z4, 5Z4G, Cv1863) Double Anode Rectifier New, Nos, old stockNew listing 50x 5C4S (5Z4, 5Z4G, Cv1863) Double Anode Rectifier New, Nos, old stock $99.99 New listing
		Raytheon Ck-5755 Clear Top Tube Nos.New listing Raytheon Ck-5755 Clear Top Tube Nos. $20.00
New listing
		Elektronika 7 Vintage Rare Soviet digital wall clock (Nos) - 690x240x95,New listing Elektronika 7 Vintage Rare Soviet digital wall clock (Nos) - 690x240x95, $199.00 New listing
		100x In17 In-17 ИН-17 Nixie Tubes Miniature Tested Ok Working Ussr Clock WatchNew listing 100x In17 In-17 ИН-17 Nixie Tubes Miniature Tested Ok Working Ussr Clock Watch $149.00
New listing
		6072 General Electric Ge 5-Star 12Ay7 Black Plate Vintage Tube 6072A Nos NibNew listing 6072 General Electric Ge 5-Star 12Ay7 Black Plate Vintage Tube 6072A Nos Nib $229.99 New listing
		Nos All American Five Radio Tube Set (Aa5): 12Av6 12Ba6 12Be6 35W4 50C5 (Rca/Ge)New listing Nos All American Five Radio Tube Set (Aa5): 12Av6 12Ba6 12Be6 35W4 50C5 (Rca/Ge) $34.95
New listing
		Ikl Boeckeler Microcode Nixie Tube Display Burroughs B-5870 National Nl-5870StNew listing Ikl Boeckeler Microcode Nixie Tube Display Burroughs B-5870 National Nl-5870St $195.00 New listing
		2) Majestic Globe Engraved Base Type 24A Antique Radio Vacuum Tubes ~ Tv-7New listing 2) Majestic Globe Engraved Base Type 24A Antique Radio Vacuum Tubes ~ Tv-7 $24.95
New listing
		One Nostung Sol 6Sl7Gt Tall Bottle TubeNew listing One Nostung Sol 6Sl7Gt Tall Bottle Tube $15.00 New listing
		Two Nos Nib Taylor Vt-62 (type 801 801-A) vacuum tubesNew listing Two Nos Nib Taylor Vt-62 (type 801 801-A) vacuum tubes $280.00
New listing
		4x 6P3S-E = 6L6Gt = 5881 Beam Tetrode Tube Valve /Nos/ Difference 2%/New listing 4x 6P3S-E = 6L6Gt = 5881 Beam Tetrode Tube Valve /Nos/ Difference 2%/ $48.00 New listing
		Philco engraved 10(Vt25) tubes Nos (Pair)New listing Philco engraved 10(Vt25) tubes Nos (Pair) $350.00
New listing
		Ken-Rad Type 42 Engraved Base Vintage Usa Vacuum Tube - Amplitrex Tested 95% GmNew listing Ken-Rad Type 42 Engraved Base Vintage Usa Vacuum Tube - Amplitrex Tested 95% Gm $25.00 New listing
		10pcs Ceramic Vacuum Tube Socket Anode Cap 9mm For 807 6146B Fu25 24A 310A ValveNew listing 10pcs Ceramic Vacuum Tube Socket Anode Cap 9mm For 807 6146B Fu25 24A 310A Valve $7.99
New listing
		Siemens E88Cc 6922 Gold Pins Vacuum Tube Strong & Balanced 11,900|10,900New listing Siemens E88Cc 6922 Gold Pins Vacuum Tube Strong & Balanced 11,900|10,900 $73.99 New listing
		2pcs 8Pin Gold Cmc Bakelite Vacuum Tube Socket For Kt88 El34 274B Hifi Audio AmpNew listing 2pcs 8Pin Gold Cmc Bakelite Vacuum Tube Socket For Kt88 El34 274B Hifi Audio Amp $15.99
New listing
		In-14 Nixie Clock (6 Nos Tube Nixie Desk Clock)New listing In-14 Nixie Clock (6 Nos Tube Nixie Desk Clock) $115.99 New listing
		Pair Of 2 Ge 6Gj7/Ecf801 TubesNew listing Pair Of 2 Ge 6Gj7/Ecf801 Tubes $2.99
New listing
		Rca 5751
00006000
 Jan Black Plate Tube Fully Tested Beautiful ( 12Ax7 )New listing Rca 5751 00006000 Jan Black Plate Tube Fully Tested Beautiful ( 12Ax7 ) $74.99 New listing
		7 X Tested 6N3P = 6Cc42=2C51=Ecc42 Doublt triod. 1978. Pcs 7.New listing 7 X Tested 6N3P = 6Cc42=2C51=Ecc42 Doublt triod. 1978. Pcs 7. $5.00
New listing
		5x Siemens zm1180 nixie tubeNew listing 5x Siemens zm1180 nixie tube $57.90 New listing
		Sylvania 6F8 Vacuum Tube Very Strong Results = 2640 µmhos 6.8 mANew listing Sylvania 6F8 Vacuum Tube Very Strong Results = 2640 µmhos 6.8 mA $43.99
Click to see more Tubes items at www.ebay.com
Prices current as of last update, 09/20/17 4:29am.

See also...
NOS Tubes, Tubes, Vintage Electronics
Other Tubes, Tubes, Vintage Electronics
Tube Sockets, Tubes, Vintage Electronics
Vacuum Tubes, Tubes, Vintage Electronics

Home Contact Resources Exchange Links ebay