What are the types of pH meters and how are they classified
Acidity meters can generally be classified according to application scenarios, instrument accuracy, reading indicators, and component types:
According to the classification of application scenarios, it can be divided into pen type pH meters, portable pH meters, laboratory desktop pH meters, and industrial pH meters. The pen type pH meter is mainly used to replace the function of pH test paper, and has the characteristics of low accuracy and convenient use. Portable pH meters are mainly used for on-site and field testing methods, requiring high accuracy and comprehensive functionality. A laboratory pH meter is a desktop high-precision analytical instrument that requires high accuracy and full functionality, some of which include printing output, data processing, and so on. Industrial pH meters are used for continuous measurement of industrial processes, which not only require measurement display functions, but also alarm and control functions, as well as considerations for installation, cleaning, anti-interference, and other issues.
According to instrument accuracy classification, it can be divided into 0.2 level, 0.1 level, 0.02 level, 0.01 level, and 0.001 level. The smaller the number, the higher the accuracy.
According to the reading indication, it can be classified into two types: pointer type and digital display type. Pointer pH meters are rarely used nowadays, but they can display continuous changes in data, so they are still used in titration analysis.
According to the type of component, it can be classified into transistor type, integrated circuit type, and single-chip microcomputer type. Nowadays, more and more microcomputer chips are used, greatly reducing instrument volume and single machine costs. However, the development cost of chips is very expensive.
What are the components of a pH meter?
1) A reference electrode: maintains a constant potential as a reference for measuring various deviation potentials;
(2) A glass electrode: its potential depends on the pH of the surrounding solution;
(3) An ammeter: This ammeter can measure small potential differences in circuits with high resistance.
The main body of the acidity meter is a precision potentiometer. When measuring, the composite electrode is inserted into the measured solution, and different electromotive forces are generated due to the different acidity (hydrogen ion concentration) of the measured solution. It is amplified by a DC amplifier, and finally the pH value of the measured solution is indicated by a reading indicator (voltmeter).
