A PHSJ-5 laboratory pH meter that can be widely used in universities, research institutes, industrial and mining enterprises and environmental chemical laboratories to measure the pH value and potential mV value of aqueous solution. Recently, it was successfully developed by our company. , has been put on the market. The laboratory pH meter is a precision pH measuring instrument equipped with self-developed data acquisition software. The technology and performance are advanced in China, which is close to the level of new products of foreign professional electrochemical laboratory instrument manufacturers. The PHSJ-5 laboratory pH meter uses a high-precision A / D conversion chip, equipped with precision pH electrode, precision reference electrode and precision temperature sensor, ensuring the instrument has a measurement accuracy of 0.001 pH, which can meet the user's precision measurement. The pH of the aqueous solution and the mV value of the potential. The instrument has five main features: one is a touch-type large-screen liquid crystal display, full Chinese operation interface, easy to use; the second is to select a variety of pH standard buffer solution calibration instruments, which is beneficial for users to establish their own standard solution group; It has the functions of automatically identifying five standard solutions; the fourth is automatic and manual temperature compensation, automatic calibration, automatic calculation of the theoretical slope of the electrode percentage; five can store, delete, print, and review, can store up to 200 sets of measurement data, and have RS -232 communication function.