How to determine the quality of the pH meter

With the popularity of pH meter, more and more users are concerned about the quality of the pH meter. Therefore, some common methods for judging the pH meter's quality are roughly discussed. From the use point of view, the pH meter's judgment is mainly reflected in:

1. Accuracy: The pH meter without accuracy has no use value. The way to judge is to use high-precision instruments or high-precision standard fluid calibration.

2, stability: an unstable pH meter reading is difficult, it is difficult to ensure the accuracy of the instrument, the stability of performance in two aspects, on the one hand is the stability of a single instrument, you can put the same instrument for a long time stable solution In the middle, to see whether the value changes and the magnitude of change; on the other hand, the stability of several instruments, the same model of several instruments to check the same type of stability in the same solution to see if the reading is consistent, the error is how much, if a few models There is no guarantee of stability between instruments, and it is difficult to ensure the accuracy and stability of each instrument.

3. Adjustment of common errors: Temperature is the most obvious factor causing PH error. Whether there is a temperature probe and the sensitivity of the temperature probe also affect the use of the instrument.

4, easy to operate, beautiful interface: Users in this regard is relatively easy to determine, some old-style instruments, the use of analog switches, resulting in difficult calibration, small changes are not easy to find, prone to fatal system errors. On the other hand, taking into account the cost and technical reasons, there are still many instruments using LED digital tube, the display content is not enough, of course, there are manufacturers to make up for this shortcoming in a certain way. At present, more commonly used convenient operation interface is generally LCD liquid crystal display keyboard operation.

5, the pros and cons of the probe: This point is no doubt that the probe's performance directly affects some of the instrument's technical indicators, and then the superior instrument with poor quality probes is of no avail.

6, security: In recent years, more and more customers began to pay attention to the safety of the operation, a well-designed instrument using a lower safety voltage input can greatly improve the safety performance.

From a technical point of view, it is mainly reflected in:

1, the design principle: the design principle is the soul of the entire machine, excellent design can reduce costs at the same time improve the accuracy, this point everyone wise see, benevolent see. However, there is a biggest difference between the analog circuit and the numerical circuit. With the development of technology and the decrease of the price of the SCM, numerical circuits have increasingly become mainstream products in recent years. Many of his advantages are incomparable with analog circuits.

2. Production process: No matter how good the design or even the best product is, if there is no good production process and inspection method, the manufacturing process is mainly reflected in the internal circuits and components. Many units consider the cost and technology, and the internal circuit is disorderly and rough. , Or use low-quality components, such instruments can not guarantee his long-term accuracy and stability and safety.