Structure and composition of pH meter
The structure of pH meter and pH meter consists of three main parts. People in the industry know that PH meter is a commonly used instrument and equipment. With the rapid development of economy, the application scope and technology are constantly expanding and updating. Various pH meters and pH meter products are used to accurately measure the pH value of liquid media, including industrial processing, food industry measurement, etc. The pH meter with corresponding ion-selective electrodes can also measure the MV value of ion electrode potential. Using PH meter and acidity meter to measure potential is a precise method to measure pH*, which is widely used in industry, agriculture, scientific research, environmental protection and other fields. For the first-time users of pH meter, let's take a look at the three main structural components of pH meter. The pH meter consists of three parts:
1. A reference electrode;
2. A glass electrode whose potential depends on the pH of the surrounding solution;
3. An ammeter, which can measure tiny potential difference in a circuit with great resistance.
The following are the main functions of each component:
1. The basic function of the reference electrode is to maintain a constant potential, which is used as a reference for measuring various deviation potentials. Silver-silver oxide electrode is a commonly used reference electrode in pH at present.
2. The function of the glass electrode is to establish a potential difference that responds to the change of hydrogen ion activity of the measured solution. Put the pH-sensitive electrode and the reference electrode in the same solution to form a primary battery, and the potential of the battery is the algebraic sum of the potentials of the glass electrode and the reference electrode. E battery =E reference +E glass, if the temperature is constant, the potential of this battery changes with the pH of the solution to be measured, but it is difficult to measure the potential generated by the battery in the pH meter because its electromotive force is very small and the impedance of the circuit is very large by 1-100 mω; Therefore, the signal must be amplified enough to drive the standard millivoltmeter or milliammeter.
3. The function of the galvanometer is to amplify the potential of the primary battery several times, and the amplified signal is displayed by the ammeter. The degree of deflection of the ammeter pointer indicates the strength of the signal it pushes. For the need of use, the dial of the pH ammeter is engraved with the corresponding pH value; While the digital pH meter directly displays the pH value in numbers.
