How Does a PH Sensor Work

A Ph sensor is an instrument used to measure a substance’s acidity. It works by measuring how acidic or basic the liquid is. It is one of the most popular and widely used sensors in industrial applications. It is used to test products, water, and many other substances. It can be a handy tool in the laboratory during experiments to determine the elements of a substance. In this article, we will discuss how the ph sensor works.

The Probe is Inserted into the Solution Under Test

The test solution, in either liquid or solid form, enters the probe. The electrodes pass through small holes at the tip of the probe so that the electrolyte in contact with both of them can act as a reference junction to measure ph. A voltage is applied between sensor plates or electrodes. However, the sensing plates are inert materials, such as platinum alloy.

The Proportions of Acidic Ions to Basic Ions in the Solution Are Measured

Generally, there are more acidic ions than basic ones within a fluid. The positive electrode attracts the acidic ions, while the negative electrode lets go of any basic ions that it is holding. The electrodes move closer by an electrical force of attraction when they both have the same voltage applied. This means that there are more acidic ions than basic ones, so the positive electrode has less distance to travel towards the negative one. This continues until equilibrium is reached.

The Probe Measures Acidic or Basic Characteristics of the Solution

The ph sensor measures equilibrium as a voltage (ΔV) between electrodes of a probe. The phenomenon known as electromotive force can be measured through this voltage. This happens when two different metals are placed in an electrolytic solution and current starts to flow between these metals producing a measurable voltage drop across the electrodes. The greater the voltage, the more acidic a solution is. The lower the voltage, the closer a solution is to be neutral or basic in composition.

Calibration of Sensor

It can also calibrate itself automatically when inserted into the test solution at the factory using advanced temperature and reference electrode calibration technology which takes place during manufacturing. It can calibrate the reference electrode every 15 minutes, making it very efficient to measure ph values.

Sensor Provides Quick Results

This patented design provides a reliable result in less than 10 seconds, providing accurate measurements of acidity or alkalinity quickly and easily for industrial applications. The sensor is only effective in testing liquids because sol

Reactions Between the Solution and Electrodes Occur

As a result of the reactions at each electrode, there will be a current flow through the electrolyte solution. In addition to this current flow, an electromotive force is generated because one electrode is more reactive than another. This difference in reactivity is called a ‘cell potential.’ The cell potential or EMF of the probe is measured between the two electrodes. It is proportional to the ph of the solution being tested.

A Calculation Is Made Based on Data from a Reference Electrode

The reference electrode is usually made up of silver chloride and potassium chloride in distilled water. In this case, the silver chloride electrode provides a constant potential. The cell EMF is measured at a known reference of ph seven from an electrolyte solution saturated with standard potassium chloride. This measurement of cell EMF can then calculate the unknown value for ph.

A Result Is Given in Terms of pH Levels

The calculated pH level is displayed. The pH scale ranges from 0 to 14 and measures the acidity or alkalinity of a solution compared to pure water with ph 7. At ph 7, water does not ionize hydrogen ions (H+) and hydroxide ions (OH-). A value of 7 means equal numbers of hydrogen and hydroxide ions in water. A pH value less than seven means that the solution is acidic and will have more H+ ions than OH- ions. The greater the difference in concentration between these two ions, the lower the ph number and thus a stronger acidity. A pH value greater than seven means that there are more OH- ions than H+ ions in the solution. The greater the difference in concentration between these two ions, the higher the ph number and thus stronger alkalinity.


A durable ph sensor is a very reliable way of testing the acidity of substances. It tests the pH levels of liquids and provides accurate results fast. The probe uses electrochemical sensing technology to give you this result, making it more efficient than chemical test kits.