The theory behind a pH meter involves determining the concentration of hydrogen ions (H⁺) in a solution using the electrochemical method. A pH meter involves a glass electrode and a reference electrode to measure the voltage produced by the hydrogen ions in the solution, which is converted into a pH value through the Nernst equation. Thus, a pH meter can precisely measure the acidity ... https://www.bionicsscientific.com/blogs/ph-meter-working-principle/