Science glossary film: Cathode

A cathode is the terminal from which electrons enter a system. In a device which consumes power the cathode is negative, and in a device which provides power the cathode is positive. In electrolysis, the cathode is the negatively charged electrode, connected to the negative terminal of an electric supply. It attracts positive ions, which then gain electrons at the cathode.

In a device which consumes power the cathode is negative, and in a device which provides power the cathode is positive. In electrolysis, the cathode is the negatively charged electrode, connected to the negative terminal of an electric supply. It attracts positive ions, which then gain electrons at the cathode.