​This pH measurement is directly related to the ratio of hydrogen ion concentration and hydroxyl ion concentration ([H⁺] and [OH^-], respectively). The following are the pH levels:

• Neutral solution: pH = 7
• Acidic solution: pH < 7
• Basic solution: pH > 7

A neutral solution will show a pH of 7 on a Digital pH meter due to the equal activities of hydrogen and hydroxide ions. Acidic solutions exhibit pH readings below 7 (higher hydrogen ion activity compared to hydroxide ion activity), and basic (or alkaline) solutions exhibit pH levels above 7 (hydroxide ion activity is greater than that of hydrogen ion).

A Digital pH meter consists of three different parts: an internal electrode, a reference electrode, and a high input impedance meter. Glass probe often contains two electrodes -- an internal electrode and a reference electrode. Inside the probe is a buffer solution at a pH of 7.

APPLICATIONS OF THE PH METER

Digital pH meters are widely used in the following industries:

• Food & beverage
• Pharmaceutical
• Oil & gas
• Agriculture
• Water treatment plant

This is not the total list of all of its areas of application.