pH meters are instruments used to measure the pH or the hydrogen-ion activity in water-based solutions. They measure the difference in electrical potential between a pH electrode and a reference electrode, hence indicating the acidity or alkalinity of a solution. Hence these are also called potentiometric pH meters, as they measure the voltage between the two electrodes and display the result converted into the corresponding pH value. Conductivity meters are used to measure the salt concentration, conductivity of a solution.

 

These devices contain a pair of electrodes and a simple electronic amplifier. The electrodes also referred to probes, are submerged into the test solution to determine the pH/conductivity. The glass electrode contains a glass bulb which is specifically designed to be selective to hydrogen-ion concentration. Hydrogen ions in the solution exchange for other positively charged ions present on the glass bulb, which creates an electrochemical potential across the bulb. The electrochemical potential developed between the two bulbs is detected by the electronic amplifier, which produces a readable output.

 

pH meter, conductivity meter, as well as in combination, is available from LabIndia on Biomall.in.