A pH sensor is a device used to measure the acidity or alkalinity of a solution, based on the concentration of hydrogen ions (pH value) in the solution. The pH value is an indicator of the solution’s acidity, typically measured on a scale from 0 to 14, where 7 is neutral, below 7 is acidic, and above 7 is alkaline.

A pH sensor typically consists of a glass electrode and a reference electrode. The surface of the glass electrode is coated with a special glass membrane containing an electrolyte solution that is sensitive to hydrogen ions. When the glass electrode is immersed in the solution, hydrogen ions in the solution react with the electrolyte inside the glass membrane, generating a potential difference and thus producing a measurement signal. The reference electrode provides a stable reference potential to ensure the accuracy and stability of the measurement.

pH sensors are widely used in laboratories, industrial production, environmental monitoring, and other fields. In laboratories, they are used to precisely measure the acidity or alkalinity of solutions for scientific research and chemical analysis. In industrial production, pH sensors are commonly used to monitor and control the acidity or alkalinity of liquids during manufacturing processes to ensure product quality and process stability. In environmental monitoring, pH sensors are used to monitor the acidity or alkalinity of water bodies, soil, etc., to assess environmental quality and ecological balance.