A pH meter is an electronic piece of equipment to determine the pH of a solution. An electrode (usually glass) is attached to the meter, which measures the voltage. As pH meters and probes require calibration before use, they can be calibrated with a standard buffer solution that is input into the machine (or it can be done without a solution) giving an accurate result. The buffer solution commonly uses the following three pH levels: pH 7, pH 4, and pH 9.2/10.
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