HT (vacuum tube) - Wikipedia

In vacuum tube technology, HT or high tension describes the main power supply to the circuit, which produces the current between anode and cathode. HT(vacuumtube) FromWikipedia,thefreeencyclopedia Jumptonavigation Jumptosearch Invacuumtubetechnology,HTorhightensiondescribesthemainpowersupplytothecircuit,whichproducesthecurrentbetweenanodeandcathode.Itisalsoknownastheplatesupplyorvoltage,Bbatterysupply,orsimplylabeled->Boncircuitdiagrams,fromthedaysofbatterypoweredcircuitry. TheHTsupplycircuitmostcommonlyprovidesapositivevoltageofsomehundredsofvoltstotheanode(orplate)andinlatercircuitsalsotothescreengrid,withthecathoderunningatneargroundorchassispotential.Themainexceptiontothiswasinthecaseoftubeswithwater-cooledanodes,onceusedforradiotransmission,electricfurnacesandsimilarapplications.ThesetubesusedanegativeHTsupplytothecathode,sothattheanodecouldrunneargroundDCpotential(buttypicallyatmanyhundredsofvoltsofRF). Otherpowersuppliestovacuumtubecircuitsinclude: LT,lowtensionorAbattery,thesupplytothefilamentsorheaters.Earlytubesdesignedforbatteryoperationhad2 voltfilaments(forusewithalead-acidcell).Latertubeshad1.4 voltfilamentstorunfromdrybatteries.Withtheintroductionofmainspoweredequipment,indirectlyheatedtubesbecamemorecommonandusually(thoughnotalways)required4 voltsinEuropeand6.3 voltsinAmerica.ThelatterbecamethestandardvoltageaftertheSecondworldwar.Onenotableexceptionwasthatrectifiertubesoftenhad5voltfilamentsorheaterswhichusuallyhadtohaveaseparatesupplyanyway. GB,gridbiasorCbattery.Usedinearlybatterypoweredequipment.Onceselfbiasingcircuitsweredeveloped,thispowersourcewasnolongerrequired. EHT,extrahightension,theacceleratorsupplytoacathoderaytube.Thissupplytypicallyrangesfrom15kVto35kV,thoughveryearlytelevisionreceiversusedvoltagesaslowas4kV. Contents 1Typicalcircuits 1.1HT 1.2EHT 2Externallinks Typicalcircuits[edit] HT[edit] TypicalHTsupplycircuitschematic TheHTsupplywasusuallyobtainedfromafullwaverectifiercircuitsimilartotheoneshown.Inthosesetsthathadnomainstransformer(theso-calledAC/DCdesign),theHTwasobtaineddirectlyfromthemainssupply,eitherwithasimplehalfwaverectifierorwithavoltagedoublercircuit. EHT[edit] Inveryearlyvacuumtubetelevisionsets,theEHTwasderiveddirectlyfromahighvoltagewindingonthemainstransformerusingahalfwaverectifier.Inlatertelevisionsets,theEHTsupplywasinvariablygeneratedbyrectifyingtheflybackpulsesfromthescanningcircuitryratherthandirectlyfromthemainssupply(apracticethatsurvivedthetransitiontotransistorcircuits).Althoughthisprovidedagreaterdegreeofsafety,thereasonforthechangewasthatthemainstransformerhadbeeneliminatedfromsetsproducedfromthe1940sonwards. Externallinks[edit] http://www.earlytelevision.org/damper.htmlEarlyTelevisionMuseumarticleonefficiencydiodes Retrievedfrom"https://en.wikipedia.org/w/index.php?title=HT_(vacuum_tube)&oldid=882286271" Categories:Vacuumtubes Navigationmenu Personaltools NotloggedinTalkContributionsCreateaccountLogin Namespaces ArticleTalk English Views ReadEditViewhistory More Search Navigation MainpageContentsCurrenteventsRandomarticleAboutWikipediaContactusDonate Contribute HelpLearntoeditCommunityportalRecentchangesUploadfile Tools WhatlinkshereRelatedchangesUploadfileSpecialpagesPermanentlinkPageinformationCitethispageWikidataitem Print/export DownloadasPDFPrintableversion Languages Addlinks