A pH meter is an electronic device used to measure the acidity or alkalinity of a solution. It provides a numerical value on a scale from 0 to 14, where 7 is neutral, values below 7 indicate acidity, and values above 7 indicate alkalinity. This tool is essential in various fields, including chemistry, biology, and environmental science. The pH meter consists of a probe that is sensitive to hydrogen ions and a digital display that shows the pH reading. Regular calibration with standard solutions is necessary to ensure accurate measurements. pH meters are widely used in laboratories, agriculture, and water quality testing.