cathode
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Related to cathodes: Cold Cathodes, Copper cathodes
cathode
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
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
cathode
[′kath‚ōd] (electricity)
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.
(electronics)
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.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
cathode
A terminal on an electrical device that has a negative charge. Current flows from the cathode to the positively charged anode; however, the electrons actually flow from the anode to the cathode. Derived from Greek, cathode and anode mean "down" and "up" respectively. See electrode, cold cathode and OLED layers. |
| Cathode Emitters |
|---|
| In vacuum tubes, the cathodes are the emitters, and the anodes are the collectors. |
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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.
Cathode
(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 Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.