Definition of Cathode

A cathode is a type of electrode that conducts electrical current, typically allowing negatively charged electrons to flow out of a device or system. In an electrical device like a battery or a diode, the cathode acts as the negatively charged terminal where current is received from an external circuit. Conversely, in electrolytic processes or electrochemical cells, the cathode attracts positively charged ions (cations) and hosts reduction reactions.


The phonetics of the keyword “Cathode” is: /ˈkæθoʊd/

Key Takeaways

  1. Cathode is the electrode where reduction takes place in an electrochemical cell, leading to a gain of electrons.
  2. In a galvanic cell, the cathode has a positive charge because it attracts the negatively charged electrons from the anode.
  3. During electrolysis, the cathode is negatively charged, providing the necessary electrons for the reduction of cations to occur.

Importance of Cathode

The term “cathode” is important in technology due to its role in various electronic devices, such as vacuum tubes, diodes, and batteries.

As the negatively charged electrode, cathodes are responsible for the flow of electrons in different processes like discharging, emission, or collection.

This flow, known as the electric current, forms the basis of modern technology as it powers devices, enables communication, and facilitates the functioning of complex circuits.

In addition, understanding the concept of cathodes and their complementary anodes is crucial to the development and optimization of current and future electronic technology, contributing to advancements in fields like renewable energy, computing, and telecommunications.


A cathode is a crucial component in several electronic devices where the flow of electric current needs to be managed, such as in batteries, vacuum tubes, and diodes. The primary purpose of a cathode is to serve as an electrode that emits or releases electrons. These electrons then travel and create an electric current, which supplies power for various electronic systems.

In batteries, for example, the cathode acts as the positive terminal, discharging the stored electrons to provide energy to the connected device. Hence, understanding the role of a cathode is vital in grasping the principles of electricity generation and management, as it is the terminus from which the flow of electrons commences. The function of a cathode can also be seen in the realm of electrochemical cells, in which chemical reactions generate the flow of electrical current.

During the redox reaction (short for reduction-oxidation reaction), the cathode attracts the positively charged ions called “cations,” allowing these ions to accept the electrons from the chemical reaction. Consequently, the reduction process takes place, converting the cations into neutral atoms or molecules. This phenomenon not only enables the generation of electricity but can also be employed in various applications, such as electroplating, to deposit a layer of material onto a surface.

Overall, the cathode plays an essential role in powering a plethora of modern-day electronic devices and applications, making it a cornerstone of technology.

Examples of Cathode

Cathode is a term used in several fields of technology, primarily in electronics and electrochemistry, to describe the negatively charged electrode by which electrons enter an electrical device. Here are three real-world examples:

Batteries: In everyday life, batteries are commonly used to power various portable electronic devices, such as smartphones, laptops, and flashlights. The cathode in a battery is where the reduction reactions take place and they accept electrons while creating an electric current. In an alkaline battery, for example, the cathode is made of manganese dioxide.

Cathode Ray Tubes (CRT): Before the advent of flat-screen displays, cathode ray tubes were widely used in television sets and computer monitors. A CRT functioned by firing electron beams from a cathode, situated at the back of the tube, towards a phosphorescent screen. The screen would emit light upon being struck by the electron beam, forming images on the screen.

Electrolysis: Electrolysis is a process used to separate elements or compounds through the application of an electric current. It is employed in various industrial applications, such as the production of aluminum and the extraction of metal from their ores. In these processes, the cathode serves as the site where the reduction reaction occurs, accepting electrons and facilitating the synthesis of the desired product.


FAQs about Cathode

What is a cathode?

A cathode is the electrode from which a conventional current leaves a polarized electrical device. It is negatively charged in a galvanic cell while positively charged in an electrolytic cell.

What is the difference between a cathode and an anode?

A cathode and an anode are both electrodes in an electrical cell, but they have opposite functions. A cathode is the negatively charged electrode in a galvanic, or voltaic, cell, from which current flows out. The anode, on the other hand, is the positively charged electrode where current flows into the cell.

What are some common uses for cathodes?

Cathodes are used in various applications such as galvanic cells, electrolytic cells, batteries, discharge lamps, cathode-ray tubes, and electroplating.

How are cathodes used in batteries?

In a battery, the cathode is the electrode where the reduction reaction occurs. During discharge, the cathode gains electrons from the external circuit, allowing positive ions to flow from the electrolyte solution and undergo reduction, which produces the energy output of the battery. The cathode is typically the positive terminal in a battery.

What is a cathode-ray tube?

A cathode-ray tube (CRT) is a vacuum tube containing one or more electron guns that produce a beam of electrons directed towards phosphorescent screen. A magnetic or electric field manipulates these electrons to create images on the screen. CRT displays have been commonly used in televisions and computer monitors prior to the advent of flat-screen technology.


Related Technology Terms

  • Anode
  • Electrolyte
  • Galvanic cell
  • Electrode potential
  • Reduction reaction

Sources for More Information


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