The repeatability error of the glass electrode of the ph meterand the solution junction potential stability of the reference electrode are not better than 0.01pH.
Therefore, the high resolution of the meter, the instrument test accuracy is difficult to better than 0.01pH.
However, choosing a high-resolution instrument can maximize or eliminate the effects of the meter on the test error.
As the electric meter to achieve satisfactory accuracy has not been a problem, so the instrument is intelligent, humane, reliable, easy to operate and cost-effective continuous innovation and improvement.
The relationship between the level of the pH meter and its test accuracy is specified in the National Metrology Verification Protocol for Acidity Meter (JJG 119-84) as follows:
PH acidity meter level 0.2, 0.1, 0.02, 0.01, 0.001
Divide the value or the minimum display value (pH) 0.2,0.1,0.02,0.01,0.001
Electric meter indication error (pH) ± 0.1, ± 0.05, ± 0.01, ± 0.01, ± 0.002
The total error (pH) of the supporting test shows ± 0.2, ± 0.1, ± 0.02, ± 0.02, ± 0.01