pHmåler

A pHmåler, or pH meter, is an instrument for measuring the acidity or basicity of a solution by determining its pH. Modern pHmeters are electronic devices that convert the voltage generated by a pH electrode into a numerical pH value. Measurement relies on the glass pH electrode, which is sensitive to hydrogen ion activity, paired with a reference electrode; the meter reads the potential difference and presents the pH after temperature compensation.

Most pHmeters are available as benchtop units or portable handheld devices. Electrode configurations include a combined electrode (glass electrode and reference in a single probe) or separate electrodes. Calibration with standard buffer solutions is essential, typically using two or three buffers such as pH 4, pH 7, and pH 10, to set the slope and offset of the electrode.

Typical accuracy is around ±0.01–0.1 pH, depending on model, probe condition, and calibration quality. Common measurement range is pH 0–14. Many meters include automatic temperature compensation (ATC) to correct readings for temperature effects on the electrode response.

Maintenance and care: keep the electrode hydrated and store in an appropriate storage solution, rinse between measurements, and clean according to manufacturer guidelines. Recalibrate regularly, especially when measuring different samples or after storage. Electrode life depends on usage, storage, and fouling; probe replacement may be necessary.

Applications include chemistry, biology, agriculture (soil pH), water quality monitoring, food and beverage, fermentation, and environmental testing.