P is a suitable
detector (a headphone or other electronic device)
and the bridge is balanced when no current passes
through the detector Under these conditions:
Unknown resistance R2 = 
1
4
3
R  R
R
(2 19)
These days, inexpensive conductivity meters are
available which can directly read the conductance or resistance of the
solution in the conductivity cell Once the cell constant and the resistance
of the solution in the cell is determined, the conductivity of the solution
is given by the equation:
cell constant
G*
R
R
 

(2