cathode
Sign in to savethumb|Diagram of a copper cathode in a [[galvanic cell (e.g. a battery). Positively charged cations move towards the cathode allowing a positive current i to flow out of the cathode.]]
AI overview
A cathode is the positive terminal in a battery or similar device where positively charged particles are attracted and where electric current flows out. It matters because it's one of the two essential parts of a battery that makes electrical current flow, which powers everything from flashlights to electronics.
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Article
14 sectionsContents
- Charge flow
- Etymology
- In chemistry
- Electrolytic cell
- Galvanic cell
- Electroplating metal cathode (electrolysis)
- In electronics
- Vacuum tubes
- Hot cathode
- Cold cathode
- Diodes
- See also
- References
- External links
thumb|Diagram of a copper cathode in a [[galvanic cell (e.g. a battery). Positively charged cations move towards the cathode allowing a positive current i to flow out of the cathode.]]
A cathode is the electrode from which a conventional current leaves a polarized electrical device such as a lead–acid battery. This definition can be recalled by using the mnemonic CCD for Cathode Current Departs. Conventional current describes the direction in which positive charges move. Electrons, which are the carriers of current in most electrical systems, have a negative electrical charge, so the movement of electrons is opposite to that of the conventional current flow: this means that electrons flow into the device's cathode from the external circuit. For example, the end of a household battery marked with a + (plus) is the cathode.