What is a cathode anode and electrode

A cathode [kaˈtoːdə] (from agr. κάθοδοςcathodos, “Way down”) is generally the negative pole, i.e. the electrode that receives electrons via the electrical connection and passes them on towards the anode. The cathode (-) is the counter electrode to the anode (+). Cations (+) migrate to the cathode and anions (-) to the anode.


In chemistry, a cathode is the electrode on which a reduction reaction takes place. Electrons are picked up via the electrical connection and given off to the chemical reaction.

An electrochemical reaction always takes place at the phase boundary between an electrode and an electrolyte solution, an ion-conducting solid or a melt. The electrons produced during the reduction move out of the cathode out into the other phase, hence the name from the Greek cathodos for down.

In electrolysis, the cathode is the negative electrode, in batteries and fuel cells it is the positive electrode. With rechargeable batteries (secondary element, accumulator) the same electrode can alternately work as an anode or cathode, depending on whether the battery is being charged or discharged.

examples for Cathode reactions:


Electrical engineering

In electrical engineering, the cathode is an electron-emitting electrode of an electron tube, fluorescent tube or an electron microscope. A distinction is made between hot cathodes, cold cathodes and photocathodes.

The pole that has to be connected to the negative pole of the supply voltage in order to receive a current is called the cathode.

Very complex cathodes can be found in systems for high-voltage direct current transmission, for example in the form of huge copper rings laid in the sea.

In this subject area is also the spelling Cathode widespread.

So-called cold light cathodes are used in PC modding.

Category: Electrochemistry