The PH meter is also called the pH meter, which is generally used to test the pH value of the liquid. The pH value is often used to judge the corrosiveness of the liquid. Classification of PH meter and acidity meter: According to the needs of production and life, people have scientifically researched and produced many types of PH meter. , 0.01 grade PH meter, acidity meter or higher precision PH meter, acidity meter. 2. According to the volume of the instrument, there are pen-type PH meter, acidity meter (mini-type PH meter, acidity meter), portable PH meter, acid-base meter, and desktop PH meter. 3. On-line PH meter and acidity meter with online continuous monitoring and measurement. 4. According to the requirements of use: pen-type PH meter, acidity meter (mini PH meter) and portable PH meter, the acidity meter is usually brought to the scene by the testing personnel for testing. 5. Select the pH meter and the accuracy level of the acidity meter is determined according to the accuracy required by the user for measurement, and then choose various shapes of pH meters and acidity meters according to the convenience of the user.