testo 240 Bedienungsanleitung Seite 44

α
Temperature coefficient at
TR
the reference temperature
Reference temperature
T
R
(25 °C with testo 240 )
Temperature
T
M
of the measured sample
Electric conductivity at the
K TR
reference temperature
Electric conductivity at the
K TM
temperature of measurement
22
Basic i i nformation o o n l l inear t t emperature
In order to enable an approximate conversion of a
conductivity, measured at any temperature, into
that at the reference temperature (e.g. 25 °C/
+75 °F), the temperature coefficients are used
according to the following equation
(see DIN 38404 part 8):
α is dependent o o n the type and the
concentration of the ions present in the solution,
but also on temperature itself .
In relevant tables (such as Landold Börnstein), α
values can be found for salty, acidic and alcaline
solutions in different types of measuring
conditions.
Should the temperature coefficients be based on
another reference temperature than that required, it
is possible to convert them with the following
equation.
You can also determine temperature coefficients
for your own particular application yourself. For this
you need to measure the conductivity of a given
solution at temperatures T
close to the reference temperature.
α
can be measured with the equation:
TR
Appendix
compensation
and T , T should be
1 2 2