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Definition: 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.