A conductivity meter is essentially an “amp meter”. Two plates made of
inert metal (e.g palladium coated platinum) are placed in the sample, an
alternating current voltage of around 1,000 cycles per second is applied
across them and the current is measured (Fig 2.2a).
Conductivity (G), is the inverse of resistivity (R) and is determined from
the voltage (E) and current (I) values according to Ohm's law i.e. G = 1/R =
I/E.
Since the charge on the ions in solution permits the conductance of
electrical current, for most solution types the conductivity will increase
with concentration.
Thus, an EC meter can be used to detect the presence of salts and their
approximate concentration in a solution.
