What is cathode?

  • (noun): A negatively charged electrode that is the source of electrons in an electrical device.
    See also — Additional definitions below


A cathode is an electrode through which electric current flows out of a polarized electrical device. The direction of electric current is, by convention, opposite to the direction of electron flow. Therefore the electrons flow into the polarized electrical device and out of, for example, the connected electrical circuit. Mnemonic: CCD (Cathode Current Departs).

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Some articles on cathode:

C. F. Varley - Cathode Rays
... In 1871, he authored a scientific paper suggesting that cathode rays were streams of particles of electricity ... Varley believed cathode radiation was caused by the collision of particles ...
Electronics and Physics Cathode - Diodes
... In a semiconductor diode, the cathode is the N–doped layer of the PN junction with a high density of free electrons as a result of doping, and an equal density of fixed positive charges ... Electrons which diffuse from the cathode into the P-doped layer, or anode, become what is termed "minority carriers" and tend to recombine there with the majority carriers, which are holes, on a timescale ... ensure a zero net current with electrons flowing from cathode to anode and recombining, and holes flowing from anode to cathode across the junction or depletion ...
Lithium-ion Capacitor - Concept of LIC
... the intercalation mechanism of Lithium batteries with the cathode of an EDLC ... The positive electrode (cathode) often employs activated carbon material at which charges are stored in an electric double layer which is developed at the interface between the carbon ... the capacity of the anode is several orders of magnitude larger than the capacity of the cathode ...
Cathode Bias
... curve, the grid element must be maintained at a bias voltage more negative than the cathode ... One method for accomplishing this is "cathode bias." ...
List Of Vacuum Tubes - European Designation, Special Quality
... and the E90CC, a double triode with a common cathode connection and seven pin base for use in cathode-coupled Flip-flops in early computers ... heater configurations inside the nickel cathode tube designed to reduce hum pickup from the A.C ... and also had improved oxide insulation between the heater and cathode so the cathode could be elevated to a greater voltage above the heater supply ...

More definitions of "cathode":

  • (noun): The positively charged terminal of a voltaic cell or storage battery that supplies current.