A technique used to control the corrosion of a metal surface by making it the cathode of an electrochemical cell. There are two main types: galvanic (sacrificial anode) protection and impressed current cathodic protection. Galvanic / Sacrificial Anode: Connects the target metal to a more active, easily corroded metal (like zinc, aluminium, or magnesium) that sacrifices itself by corroding instead. Impressed Current (ICCP): Uses an external DC electrical power source (such as a transformer rectifier) connected to an inert anode to drive a protective current onto the metal surface.