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!


This site contains sponsored affiliate links.

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!]

Matched Quad( 0% tol.) 6P3S-E (6L6 / 5881 /6L6G) Tubes Gold Grid Nos Otk /RhomusMatched Quad( 0% tol.) 6P3S-E (6L6 / 5881 /6L6G) Tubes Gold Grid Nos Otk /Rhomus $99.00 New Current Matched Quad (4) Reissue Genalex Gold Lion Kt66 6L6 Vacuum TubesNew Current Matched Quad (4) Reissue Genalex Gold Lion Kt66 6L6 Vacuum Tubes $280.86
In-14 Nixie Tubes Ussr unsoldered Tested unused for Nixie Tubes Clocks 6 Pcs SetIn-14 Nixie Tubes Ussr unsoldered Tested unused for Nixie Tubes Clocks 6 Pcs Set $84.95 Lot (100) Assorted/Mixed Vacuum Tubes - Radio/Ham/Tv (Grab Bag, Free Shipping)Lot (100) Assorted/Mixed Vacuum Tubes - Radio/Ham/Tv (Grab Bag, Free Shipping) $49.95
New Listing5 4Cx150A Vacuum Tubes 4 Eimac Plus One SocketNew Listing5 4Cx150A Vacuum Tubes 4 Eimac Plus One Socket $39.95 New ListingLot Of Fourten (14) Preamp Tubes 12Dw7, 6Eu7, 7308 Etc Untested No ReserveNew ListingLot Of Fourten (14) Preamp Tubes 12Dw7, 6Eu7, 7308 Etc Untested No Reserve $19.92
(4) Apex or Tad Matched Jj Electronic Kt88 Power Tubes for Audio Research(4) Apex or Tad Matched Jj Electronic Kt88 Power Tubes for Audio Research $284.00 New ListingLot of (2) Tested 1U5 Tubes Diode Sharp Cutoff Pentode Zenith and Rca TubesNew ListingLot of (2) Tested 1U5 Tubes Diode Sharp Cutoff Pentode Zenith and Rca Tubes $15.00
El34 / 6Ca7 - Audio Guitar Amplifier Ham Radio Tv tube - set of (4)El34 / 6Ca7 - Audio Guitar Amplifier Ham Radio Tv tube - set of (4) $94.42 Vintage 12Sk7 Vacuum Tubes  Tung-Sol Raytheon Nos Nib *Tested* Vt-131Vintage 12Sk7 Vacuum Tubes  Tung-Sol Raytheon Nos Nib *Tested* Vt-131 $4.59
Brand New Matched Quad (4) Genalex Gold Lion Reissue Kt88 / 6550 Vacuum TubesBrand New Matched Quad (4) Genalex Gold Lion Reissue Kt88 / 6550 Vacuum Tubes $368.23 New Sovtek 6L6Wxt+ Matched *Pair* Tubes 6L6 5881 Super Power ValvesNew Sovtek 6L6Wxt+ Matched *Pair* Tubes 6L6 5881 Super Power Valves $49.99
New ListingOne 1957 Rca 6Sn7Gtb tube - Hickok Tv7B tests @ 81/78, min:50/50New ListingOne 1957 Rca 6Sn7Gtb tube - Hickok Tv7B tests @ 81/78, min:50/50 $8.50 Lot of (2) Rca 6Ge5 Electronic TubesLot of (2) Rca 6Ge5 Electronic Tubes $13.99
Brand New Matched Quad (4) Jj El84 6Bq5 Fully Tested Guaranteed Vacuum TubesBrand New Matched Quad (4) Jj El84 6Bq5 Fully Tested Guaranteed Vacuum Tubes $76.23 Vacuum Tube Led Night Light 12Ax7 Ecc83 Style White Automatic Light SensingVacuum Tube Led Night Light 12Ax7 Ecc83 Style White Automatic Light Sensing $19.36
6Sn7Gt Vintage Tubes - Various Brands - Tung Sol, Ge, Rca, Etc. All Tested6Sn7Gt Vintage Tubes - Various Brands - Tung Sol, Ge, Rca, Etc. All Tested $7.95 New In Box Gain Matched Quad 4 Jj Electronics Tesla 12Ax7 Ecc83-S Vacuum TubesNew In Box Gain Matched Quad 4 Jj Electronics Tesla 12Ax7 Ecc83-S Vacuum Tubes $77.62
New Gain Matched Quad (4) Tung-Sol Reissue 12Ax7 Ecc83 Tubes - Authorized DealerNew Gain Matched Quad (4) Tung-Sol Reissue 12Ax7 Ecc83 Tubes - Authorized Dealer $105.03 New ListingAllen Organ Type 75 / 6550 Mono Tube Amplifier 200 Wts for Restoration, No TubesNew ListingAllen Organ Type 75 / 6550 Mono Tube Amplifier 200 Wts for Restoration, No Tubes $195.00
Factory Matched Quad Tube Amp Doctor Tad 6L6 6L6Wgc-Str Red Base Short bulb.Factory Matched Quad Tube Amp Doctor Tad 6L6 6L6Wgc-Str Red Base Short bulb. $170.00 New Listing3 Nos Perfect Matched Trio 10M Mullard 12ax7 tubes ecc83 Gold Pins Great BritianNew Listing3 Nos Perfect Matched Trio 10M Mullard 12ax7 tubes ecc83 Gold Pins Great Britian $1,495.00
New Mesa Boogie El34 Pair El 34 Power Tubes in Original BoxNew Mesa Boogie El34 Pair El 34 Power Tubes in Original Box $69.99 Pair of Jj 6Sl7 Preamp Vacuum TubePair of Jj 6Sl7 Preamp Vacuum Tube $25.00
6aQ5 6005 Nos Vacuum Tube6aQ5 6005 Nos Vacuum Tube $4.99 New ListingLot Of Sixteen (16) 12Ax7 Preamp Tubes Us Gb Yugoslavia Etc Untested No ReserveNew ListingLot Of Sixteen (16) 12Ax7 Preamp Tubes Us Gb Yugoslavia Etc Untested No Reserve $23.30
100x 6N2P ~ 12Ax7, Ecc83 Double Triode Tube Voskhod Soviet 1970's New & Sl. Used100x 6N2P ~ 12Ax7, Ecc83 Double Triode Tube Voskhod Soviet 1970's New & Sl. Used $159.59 General Electric Ge 5670W Tubes (10)General Electric Ge 5670W Tubes (10) $52.50
Tubes 2 new Philips 6X4W black plates 6X4Wa 6X4 Nos Nib Usa factory matchingTubes 2 new Philips 6X4W black plates 6X4Wa 6X4 Nos Nib Usa factory matching $39.99 New ListingGeneral Electric Ge Tube Amp 7700 Stereo Classic Amplifier 6973 No Tubes RepairNew ListingGeneral Electric Ge Tube Amp 7700 Stereo Classic Amplifier 6973 No Tubes Repair $250.00
Brand New Gain Matched Trio (3) Mullard Reissue 12Ax7 Long Plate Vacuum TubesBrand New Gain Matched Trio (3) Mullard Reissue 12Ax7 Long Plate Vacuum Tubes $83.80 Sleeve Of 5 Philips Jan 12At7Wc TubesSleeve Of 5 Philips Jan 12At7Wc Tubes $69.00
new Matched quad 6L6Gc vacuum tubesnew Matched quad 6L6Gc vacuum tubes $48.99 New ListingLot of (4) Tested 6Bl7Gta and 6Bl7Gt Tubes Twin Triode Tubes Sylvania CrosleyNew ListingLot of (4) Tested 6Bl7Gta and 6Bl7Gt Tubes Twin Triode Tubes Sylvania Crosley $30.00
New 1x Jj Electronics 12Ax7 / Ecc83 | One / Single Tube | Free ShipNew 1x Jj Electronics 12Ax7 / Ecc83 | One / Single Tube | Free Ship $21.75 (1) Electron Tube Ge Jan 5670w Twin Triode Vacuum tubes. Nos(1) Electron Tube Ge Jan 5670w Twin Triode Vacuum tubes. Nos $12.00
Wwii Pair Hytron Jan Vr150-30 Vt139 ( Od3) Vacuum Tube - New Old Stock - UsaWwii Pair Hytron Jan Vr150-30 Vt139 ( Od3) Vacuum Tube - New Old Stock - Usa $16.99 1 x Nos Nib 5751 12Ax7 Ge Tube - 539C Tested - 7 Tubes Available1 x Nos Nib 5751 12Ax7 Ge Tube - 539C Tested - 7 Tubes Available $30.00
6p6s 6п6с Reflector ( 6L6 ) matched quad soviet vintage tested tube lot 4pcs6p6s 6п6с Reflector ( 6L6 ) matched quad soviet vintage tested tube lot 4pcs $22.95 12Au7 6189 5814a - Vintage Tube - Rca, Sylvania, Raytheon, Ge Etc. - All Tested12Au7 6189 5814a - Vintage Tube - Rca, Sylvania, Raytheon, Ge Etc. - All Tested $4.95
Audio Tubes - sleeve of 5 new Rca 6Gh8A factory matching Nos Nib Usa testedAudio Tubes - sleeve of 5 new Rca 6Gh8A factory matching Nos Nib Usa tested $35.99 New Listing2 matched 1943-44 Rca 6Sj7 tubesNew Listing2 matched 1943-44 Rca 6Sj7 tubes $17.85
Lot Of 4 Nos Rca Jrc 12At7Wa Tube Black Plates Amplitrex Tested Multiple AvailLot Of 4 Nos Rca Jrc 12At7Wa Tube Black Plates Amplitrex Tested Multiple Avail $55.00 Brand New Plate Current Matched Pair Mullard Reissue El84 / 6Bq5 Vacuum TubesBrand New Plate Current Matched Pair Mullard Reissue El84 / 6Bq5 Vacuum Tubes $69.04
Vintage Used 12Av7 Vacuum Tubes.Tested Good-Multiple Item DiscountVintage Used 12Av7 Vacuum Tubes.Tested Good-Multiple Item Discount $9.99 35W4 Vacuum Tube Nos35W4 Vacuum Tube Nos $5.75
Aa5 Radio Tube Set 50L6Gt 35Z5Gt 12Sa7 12Sk7 12Sq7 Hallicrafters S38 A & BAa5 Radio Tube Set 50L6Gt 35Z5Gt 12Sa7 12Sk7 12Sq7 Hallicrafters S38 A & B $19.95 Vintage Nos 6X4 Vacuum Tubes.Tested Good-Multiple Item DiscountVintage Nos 6X4 Vacuum Tubes.Tested Good-Multiple Item Discount $9.99
Matched Pair Mullard 12Ax7 tubes, Brand New in Box !Matched Pair Mullard 12Ax7 tubes, Brand New in Box ! $49.76 New ListingOa2 tubes - set of Three (3) - tested and workingNew ListingOa2 tubes - set of Three (3) - tested and working $12.00
New ListingLot Of Eighteen (18) 12Ax7 Amplifier Preamp Tubes Us Gb Etc Untested No ReserveNew ListingLot Of Eighteen (18) 12Ax7 Amplifier Preamp Tubes Us Gb Etc Untested No Reserve $23.30 New old stock Rca 3B28 vacuum tube Multiples availableNew old stock Rca 3B28 vacuum tube Multiples available $20.00
Nos 1960s Valvo 12Au7 Ecc82 Holland Matched Pair Tubes Same Factory As Bugle BoyNos 1960s Valvo 12Au7 Ecc82 Holland Matched Pair Tubes Same Factory As Bugle Boy $187.00 Kt77 - Jj Electronics Matched (4) Vacuum TubesKt77 - Jj Electronics Matched (4) Vacuum Tubes $145.00
Pair, Rca Type 6Sl7Gt Radio/Audio Tubes, Nos, MatchedPair, Rca Type 6Sl7Gt Radio/Audio Tubes, Nos, Matched $45.00 New 2x Jj El84 / 6Bq5 | Matched Pair / Duet / Two | Power Tubes | Free ShipNew 2x Jj El84 / 6Bq5 | Matched Pair / Duet / Two | Power Tubes | Free Ship $38.49
Ce-2-T Continental Electronics Photo tube - Beautiful new in package tubes.Ce-2-T Continental Electronics Photo tube - Beautiful new in package tubes. $14.25 5U4Gb Ga Vintage Tube - Rca, Raytheon, Cbs, Sylvania, & Etc. - Tested5U4Gb Ga Vintage Tube - Rca, Raytheon, Cbs, Sylvania, & Etc. - Tested $3.95
Click to see more Tubes items at www.ebay.com
Prices current as of last update, 07/19/24 2:20am.

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