Acidity meter is a common equipment,also known as PH meter, which is mainly used for precise measurement of pH value of liquid medium, and can also measure MV value of ion electrode potential with corresponding ion selective electrode. It is widely used in industry, agriculture, scientific research, environmental protection and other fields. If the electrode an be properly maintained in use, prepare the standard buffer solution as required and operate the electrometer correctly, which can remarkably reduce pH indication error, so as to improve the reliability of chemical experiment and test data.

Taking the acidity meter produced by Kelilong Electron Co.Ltd in Fujian,China as an example. It usually divided into four categories: industrial on-line acidity mete, table type acidity meter, portable acidity meter and pen type acidity meter.as shown in Figure 1.