An indicator electrode is a type of electrode used in electrochemical measurements to detect the concentration of specific ions in a solution. It responds to changes in the chemical environment, providing a measurable signal that correlates with the concentration of the target ion. Commonly used in pH meters, the indicator electrode helps determine acidity or alkalinity by measuring the hydrogen ion concentration. These electrodes are often paired with a reference electrode, which maintains a constant potential. Together, they form a complete electrochemical cell, allowing for accurate readings. The performance of an indicator electrode can be influenced by factors such as temperature and the presence of interfering substances.