Cathode

cathode, electrode through which current leaves an electric device. In electrolysis, it is the negative electrode in the electrolytic cell.

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cathode

Terminal or electrode at which electrons enter a system, such as an electrolytic cell or an electron tube. In a battery or other source of direct current, the cathode is the positive terminal. In a passive load it is the negative terminal. In an electron tube, such as a cathode-ray tube, electrons stream off the cathode and travel through the tube toward the anode.

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cathode

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.

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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

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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.

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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.