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What's pH Meter Working Principle?

What's pH Meter Working Principle?

2022-03-25

What’s pH Meter Working Principle?

A pH meter is made of a few vital components such as Measuring Electrode, Reference Electrode, Temperature Sensor.

The pH Meter estimates the voltage of an electrochemical cell and based upon the Temperature Sensor defines the pH of a suspension.

Most of the pH meters contain Combination Electrodes, in which the pH electrodes and the Temperature Sensor are fabricated within a single frame.

The algebraic total of the potentials of the Measuring Electrode, Reference Electrode, and the Liquid Junction is known as the overall potential or the voltage.

The Reference Electrode contains a neutral solution such as Potassium Chloride solution with a fixed concentration. It gives a stable voltage.

On the opposite, the potential of the Measuring Electrode depends totally upon the pH of the suspension.

The potential variation (voltage) between a pH glass membrane of pH Measuring Electrode and a Reference Electrode which is immersed in the Sample Liquid to be examined is estimated.

When the two Electrodes are immersed into the Sample Suspension, the ion-exchange process transpires wherein some of the Hydrogen ions flow towards the outside surface of the Measuring Electrode and displace some of the metal ions within it.

Likewise, some of the metal ions migrate from the Glass Electrode toward the Sample Suspension. The responsiveness of the Reference Electrode potential to variation in pH is negligible or it is unaffected by variations in pH and therefore produces a stable voltage.

on-exchange processes additionally take place on the interior surface of the Glass Electrode from the sample suspension.

This generates a potential variation (Hydrogen- ion activity) among them. The Liquid Junction potential is normally minute and almost constant which essentially depends on the intensity of the ions in the sample suspension.

Every three potentials are summed up and ranked by High Impedance Voltmeter.

The potential voltage generated beyond the Glass Electrode membrane is temperature-dependent, by a temperature coefficient of around 0.3% per °C.

The pH Meters hold provisions to improve the pH Measures as the temperature changes and it is termed as Automatic Temperature Compensation (ATC).

The output of the Impedance Voltmeter is Voltage studies and it possesses to be calibrated to prepare precise pH Measurement.

Calibration is performed by immersing the Measuring Electrode into Buffer Liquid of known pH which assists in understanding millivolt reading as pH measurement of the Sample Suspension at the delivered temperature.

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