Hanna Instruments hi 8819 User Manual

13

The conductivity of an aqueous solution is the measure of its ability to
carry an electrical current by means of ionic motion. The conductivity
invariably increases with increasing temperature. It is affected by the
type and number of ions in the solution and by the viscosity  of the
solution itself. Both parameters are temperature dependent. The de-
pendency of conductivity on temperature  is expressed as a relative
change per degree Celsius at a particular temperature, commonly as
percent/°C. Acids, alkalis and concentrated salt solutions have  lower
values, typically 1.5%/°C. Since a small difference in temperature
causes a large change in conductivity  readings particularly at high
and low temperatures, the readings are usually normalized at 25°C.
The HI8819 manually compensates for temperature differences with a
fixed ß at 2%.
The  HI8820  automatically compensates for temperature differences
with a built-in NTC sensor circuitry. A knob  is also provided to adjust
the temperature coefficient manually  from 0% (without compensa-
tion) to 2.5% per degree Celsius.