anode

An anode is the electrode in a polarized electrical device through which current flows in from an outside circuit.

Conversely, a cathode is the electrode in a polarized electrical device through which current flows out. Cathodes get their name from cations (positively charged ions) and anodes from anions (negatively charged ions).

In a device that consumes electricity, the anode is the charged negative electrode. Such devices include diodes, electrolytic cells in hydrogen production, and secondary battery cells in recharging batteries. However, in a device that produces power, the anode is the negative terminal, due to the flow of electrons being reversed. Such devices include electrolytic cells in hydrogen production, vacuum tubes, cathode ray tubes, oscilloscopes and primary battery cells (this includes all non-rechargeable batteries).

In many applications, since the anode releases electrons to produce current, it gradually breaks down due to the weakening of the bonds between the cathode’s atoms.