kathode

A scientist connects a wire to the kathode of a battery.

Definition

1. Noun:
   • Electrode in an electrical device: A "kathode" is the negatively charged electrode by which electrons enter a device, such as a battery, vacuum tube, or electrolytic cell. It is the opposite of the anode (positive electrode).
   • Source of electrons: In physics and electronics, the "kathode" emits electrons during processes like thermionic emission or electrolysis.

Usage Examples

• (The negative electrode emits electrons when heated.)
• (Positively charged ions are attracted to the negative electrode.)
• (The negative terminal of the battery.)

Advanced Usage

• "Kathode ray": a stream of electrons emitted from a kathode in a vacuum tube.

  • Kathode rays were discovered in the 19th century and led to the invention of the cathode ray tube. (Electron beams from the kathode.)

• "Kathode follower": a type of electronic circuit where the output voltage follows the input voltage, using a kathode as the output terminal.

  • The kathode follower amplifier provides high input impedance. (A circuit design using the kathode.)

Variants and Related Words

• Cathode (n): an alternative spelling of "kathode," more common in modern usage.

  • The cathode in a diode is marked with a stripe. (The negative electrode in an electronic component.)

• Kathodic (adj): relating to or characteristic of a kathode.

  • Kathodic protection is used to prevent metal corrosion. (A technique using a kathode to protect metal.)

Synonyms

• Negative electrode: the terminal in a device that attracts positive ions or emits electrons.
• Emitter: a term sometimes used for the kathode in vacuum tubes.

Related Idioms

• No common idioms exist for "kathode," as it is a technical term.