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terminal through which electric current passes between metallic and nonmetallic parts of an electric circuit. In most familiar circuits current is carried by metallic conductors, but in some circuits the current passes for some distance through a nonmetallic conductor.
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 through which current leaves an electric device. In electrolysiselectrolysis
, passage of an electric current through a conducting solution or molten salt that is decomposed in the process. The Electrolytic Process

The electrolytic process requires that an electrolyte, an ionized solution or molten metallic salt, complete an
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, it is the negative electrode in the electrolytic cell.



(1) In an electron tube or a gas-discharge tube, the electrode that is the source of electrons that ensure the conductivity of interelectrode space in a vacuum or maintain the steadiness of the passage of an electric current through the gas. Depending on the mechanism of emission of electrons, there exist thermionic cathodes, photocathodes, and cold cathodes.

(2) The negatively charged electrode (pole) of a source of current (galvanic cell, storage battery).

(3) The electrode of an electrolytic cell, an electric arc, and other similar devices that are connected to the negative pole of a source of current.


The terminal at which current leaves a primary cell or storage battery; it is negative with respect to the device, and positive with respect to the external circuit.
The primary source of electrons in an electron tube; in directly heated tubes the filament is the cathode, and in indirectly heated tubes a coated metal cathode surrounds a heater. Designated K. Also known as negative electrode.
The terminal of a semiconductor diode that is negative with respect to the other terminal when the diode is biased in the forward direction.
(physical chemistry)
The electrode at which reduction takes place in an electrochemical cell, that is, a cell through which electrons are being forced.


1. the negative electrode in an electrolytic cell; the electrode by which electrons enter a device from an external circuit
2. the negatively charged electron source in an electronic valve
3. the positive terminal of a primary cell


The terminal on a device that emits current. In the cathode ray tubes (CRT) of the bulky TVs and monitors prior to flat panels, the negative cathode emits electrons that are attracted to the positive "anode." Current flows out of cathodes and into anodes. Depending on the application, a cathode may be considered positive or negative. Derived from Greek, cathode and anode mean "down" and "up" respectively. See electrode and cold cathode.

Cathode Emitters
In vacuum tubes, the cathodes are the emitters, and the anodes are the collectors.
References in periodicals archive ?
Moreover, the development of a safer cathode material may solve problems that researchers have encountered while working to manufacture large lithium-ion batteries, Blomgren says.
If under humid conditions a cell has too much water at the cathode, oxygen can't get to the electrode, and the fuel cell shuts down.
In existing Hall effect thrusters, a single high-temperature cathode generates the electrons.
2] powder cathode have been passed through a pressing/sintering process.
As compared to the more commonly employed thermionic cathode approach for electron-beam formation, plasma cathode or plasma electron emitter approaches can produce greater emission current density, are capable of pulsed beam generation, can operate over a wide range of back-ground gas pressure, and are only weakly dependent on the residual vacuum conditions, among other advantages which make them attractive for applications such as electron-beam welding and powder cladding, modification of material surface properties, generation of electromagnetic raditaino, plasma chemical and radiation technologies, and more.
The cathode chamber harbors oxygen dissolved in water.
From the viewpoint of state-of-the-art chemistry of solid body [2], process of the cathode activation is a process of destoichiometrization of oxides.
It recovers and recycles electrical, electronic and computer-related equipment and also operates a plant dedicated to the recycling of cathode ray tubes from TVs and computer monitors.
As the voltage increased, the amount of fluid imbibed in the rubber significantly increased, particularly at the cathode of the cell and to a lesser extent at the anode.
Of the four components (Cathode, Anode, Electrolyte and Separator) of Li-ion secondary battery, cathode material accounts for about 30-40% of Li-ion secondary battery cost.
BASF and Toda Kogyo Corp have entered into a joint venture BASF Toda Battery Materials LLC for offering cathode active materials (CAM) for lithium-ion batteries in Japan.
In APL Materials Paper, Researchers Show how to Keep Cathode Material 'In Line' to Enhance Performance