Material specific conductivity measurement - uses comparison with reference material at same temp. whose conductivity varies as same function of temp.

摘要

The specific conductivity of a material is determined from measuring its conductance at a given tamp. Then a reference material conductivity is measured, whose conductivity varies as the same function of temp. It is measured at the same temp. as that of the tested material, and the two conductivity values are compared. In appts. using this method the outputs of the measuring (5) and reference (7) sensors are alternately coupled to an eddy current tester (17) via the contacts (15) of a synchronous switch. Working synchronously with the contacts (15) are further contacts (19, 21, 23) so that the sensor signals are alternately evaluated. A sensitivity adjuster (25) balances the degree of sensitivity of the sensors.