| 摘要 |
PURPOSE:To measure electric resistance of a material to be measured without contact by supplying AC voltage from one of a pair of electrodes placed opposite to the metallic material and connecting the other electrode to a charge amplifier and comparing the applied AC voltage and the output of the amplifier. CONSTITUTION:A detector 50 is placed opposite to a metallic material 51. The detector 50 is constituted with an electrode plate 1 and 2 and a sealed case which is for blocking the effect of floating capacity. The electrode plate 2 is supplied alternating current from an AC oscillator 4 and the electrode plate 1 is connected to a charge amplifier 5. If the distance between the detector 50 and the metallic material 51 is constant by 1, electro-static capacities C0-C2 become constant, but due to the difference of the electric resistances of materials the circuit impedance Z changes, and the current (i) that flows also changes. The electric charge (q) that is detected by a charge amplifier 5 is input to a signal handling device 10 to seek the applied AC voltage and phase difference, and electric resistance is obtained by an arithmetic unit 11. With this arrangement electric resistance of a metal that is moving or a metal that is at high temperature can be measured without contact. |
