| 摘要 |
PURPOSE:To facilitate calibration immediately before measurement and to enable the automation of a calibrating operation, by switching a ground terminal and an input terminal by a selector switch of a probe, and by detecting the state of the selector switch by a switch signal detecting circuit. CONSTITUTION:The input terminal line 5 and the earth line 8 of a probe 1 are connected to a voltage measuring unit 2 by connectors 12a and 12b, and a ground contact terminal 6 is made to hold the place of a body to be measured whereat the potential thereof becomes the ground potential, so as to calibrate the ground potential. When an operation button 10 is slided for operation, a switch S is excited, a contact NC is disconnected from a contact CO, a contact NO is made to contact with the contact CO, the potential of the body to be measured is applied to a high-input impedance circuit 14, and thereby a voltage is measured. |
