Difference Between Anode and Cathode

Anode vs Cathode

Anodes and Cathodes are electrodes with opposite polarity. To know the difference between anode and cathode, we first need to understand what they are. Anodes and Cathodes are electrodes that are used for conducting electric current into or out of any device that makes use of electricity. An electrode is a conducting material that allows current to be passed through it. It is usually made of metals like copper, nickel, zinc etc, but some electrodes are made of non metals such as carbon. An electrode completes a circuit by passing current through it.

An electrode can be either anode or a cathode. The electrode at which current leaves the cell and where oxidation takes place is called anode. It is also called positive electrode. On the other hand, electrode at which current enters the cell and reduction takes place is called cathode. It is also called negative electrode. This holds true in most electric devices but in electric batteries, it is anode that becomes negative and the cathode, positive. There are even bipolar electrodes that can function as both anodes and cathodes.

A simple battery consists of three major parts which are anode, cathode and an electrolyte. Traditionally, the electrodes are at ends of the battery. When these ends are connected with electricity, a chemical reaction is started inside the battery. Electrons get disturbed and have to reorganize. They repel each other and move towards cathode which has less electrons. This balances electrons throughout the solution called electrolyte.

In general current flows out of cathode when the device is discharging but the direction of current is reversed when the device is being charged and the cathode starts to function as an anode while the anode becomes a cathode.

Cathodes and anodes are found in any device that is used for drawing electric current. It can be said that the words anode and cathode are used for identifying the polarity of the device when it is used.

In a primary cell or a battery, the terminals are non reversible which means that a cathode will always be negative. This is because the device is always used to discharge electric current. But in case of secondary cells or batteries, the electrodes are reversible as the device discharges, but also receive current for charging.

Summary:

Cathodes and anodes are terminals of any electric device that is used for providing electric current.

Anode is positive terminal while cathode is negative terminal.

The device starts to provide current when these electrodes are connected and the circuit is complete.

  • Fake_1

    Very Well Written. 5/5

  • Dave

    So is the physical composition of the two electrodes the same or different? If their composition is the same, how do you switch them around for an opposite effect? In trans-cranial Direct Stimulation (TDCS) the anode electrode is positively charged and the cathode negatively charged, which increases stimulation. But there are comments I’ve seen, where they’re switched so that the anode is negative and the cathode is positive in order to reverse current flow to get a calming effect.