AskDefine | Define cathode

Dictionary Definition

cathode

Noun

1 a negatively charged electrode that is the source of electrons in an electrical device [ant: anode]
2 the positively charged terminal of a voltaic cell or storage battery that supplies current [ant: anode]

User Contributed Dictionary

English

Pronunciation

  • IPA: /ˈkæ.θod/
  • Schoolbook Phonetics: (kăʹthōd)
  • Last Resort Phonetics: KA(TH)-thode

Noun

  1. the electrode of an electrochemical cell at which reduction occurs
  2. the negative terminal of an electrolytic cell
  3. the positive terminal of a galvanic cell
  4. the electron-emitting electrode of an electron tube

Translations

the electrode of an electrochemical cell at which reduction occurs
  • German: Kathode
the negative terminal of an electrolytic cell
  • German: Kathode
the positive terminal of a galvanic cell
the electron-emitting electrode of an electron tube
  • German: Kathode
  • Hungarian: katód

See also

French

Noun

cathode
  1. cathode

Extensive Definition

In a semiconductor diode, the cathode is the N–doped layer of the PN junction. Initially, the N-doped layer supplies electrons to flow into the junction (N-doped for negative charge carriers). The electrons given by the N-doped layer combine with 'holes' supplied from the P-doped layer. The electrons and holes combining create a 'depleted' zone at the junction, leaving behind in the cathode a thin layer of positive ions which gives a base positive charge to the junction's cathode side of the device. (The anode side has a base negative charge at the junction, since it supplied 'holes' to the recombinant region and the doped ions have one electron more than their full valence shell of electrons). As a negative charge is applied to the cathode from the circuit external to the diode, more N-doped ions are able to supply electrons to the recombinant region and the diode becomes conductive, which allows electrons to flow though the diode from the cathode to the anode (electrons flow from the N-doped to the P-doped side when the bias is overcome). Like a typical diode, there is a fixed anode and cathode in a zener diode, but it will conduct current in the reverse direction (electrons from anode to cathode) if its breakdown or Zener voltage is exceeded.

See also

References

cathode in Asturian: Cátodu
cathode in Azerbaijani: Katod
cathode in Bosnian: Katoda
cathode in Bulgarian: Катод
cathode in Czech: Katoda
cathode in Danish: Katode
cathode in German: Kathode
cathode in Spanish: Cátodo
cathode in Esperanto: Katodo
cathode in French: Cathode
cathode in Galician: Cátodo
cathode in Croatian: Katoda
cathode in Ido: Katodo
cathode in Indonesian: Katoda
cathode in Icelandic: Bakskaut
cathode in Italian: Catodo
cathode in Latvian: Katods
cathode in Lithuanian: Katodas
cathode in Dutch: Kathode
cathode in Japanese: カソード
cathode in Norwegian: Katode
cathode in Novial: Katode
cathode in Polish: Katoda
cathode in Portuguese: Cátodo
cathode in Russian: Катод
cathode in Slovak: Katóda
cathode in Slovenian: Katoda
cathode in Serbian: Катода
cathode in Serbo-Croatian: Katoda
cathode in Finnish: Katodi
cathode in Swedish: Katod
cathode in Thai: แคโทด
cathode in Turkish: Katot
cathode in Ukrainian: Катод
cathode in Chinese: 陰極
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