NAVI D-25 Instruction Manual page 203

7 Reference
7.4 Conductivity measurement
192
in Ω) is in inverse proportion to the area A (expressed in
2
m ) of the pole plates, as is the case with metal and
other conductors, and is proportional to the distance l
(expressed in m) between the two pole plates. These
relationships are expressed by equation 1, below.
R = r x l/a = rJ (Equation 1)
R: Resistance (Ω)
r: Specific resistance (Ω⋅m)
a: Pole plate area (m
l: Distance between pole plates (m)
J: Cell constant (m
Specific resistance (expressed in Ω⋅m) is an index that
indicates the difficulty with which current flows and is a
constant determined according to the solution. The
inverse of r (expressed in Ω⋅m), which is L (and is equal
to 1/r), is called the "specific conductivity" and is widely
used as an index to express the ease with which current
flows. Specific conductivity L is generally referred to as
simply "conductivity" and is expressed in units of S/m.
Inserting conductivity L (expressed in S/m) into equation
1 results in equation 2, below.
R = J/L (Equation 2)
As is clear from equation 2, when a conductivity cell
having a cell constant J of 1 m
when a conductivity cell having two pole plates that each
have an area a of 1 m
each other such that the distance l between the two
plates is 1 m is used) the inverse of the resistance R of
the solution (expressed in Ω) between both pole plates
is the conductivity. Conductivity is defined in this way,
but it changes according to the temperature of the
solution.
The conductivity of a solution is generally expressed as
the value when the solution is 25ºC.
2
)
-1 )
-1
is used (in other words,
2 and are positioned parallel to
HORIBA