Friday, April 13, 2018

Learn How a pH Sensor Works

pH Sensor
pH Sensor (Mettler)
The video below will provide you with a basic visual understanding of the design of pH sensors and the principles behind pH probe operation. Before viewing the video, here are some pH basics:

What is pH measurement?

pH (potential of hydrogen) is a figure used to express the acidity or alkalinity of a solution on a logarithmic scale. On this scale 7 is neutral; lower values are more acidic and higher values are more alkaline, with a maximum measurement of 14. In process applications, pH is generally measured with an inline pH probe, the most common being the glass combination electrode. Additionally, an inline pH probe generally requires a process adaption, cable and transmitter.

How does a pH probe work?

A typical combination pH probe is made up of two separate electrodes built into one, a pH sensing electrode, and a reference electrode. In the simplest terms, a pH sensing electrode uses a special pH sensing glass membrane. H+ ions permeate the membrane creating a charge. The potential between the two electrodes is the measurement of hydrogen ions in the solution, giving the measure of pH. For more details, download the free pH Theory Guide.

What is the difference between a pH probe, a pH sensor and a pH electrode?

Absolutely nothing! The three terms are used interchangeably in the industry. They can be used for probes that are used in-process or in laboratory measurement. You may also hear the term "pH meter". This can be used for a piece of laboratory equipment, or the term pH meter can also be used to mean the combination of an inline pH probe, cable and transmitter.