公开(公告)号：US3808521A

公开(公告)日：1974-04-30

申请号：US20318771

申请日：1971-11-30

Applicant: NAT RES DEV

Inventor： PICKARD K ,  ASPINALL A ,  WILLIAM D

IPC: G01R27/18 ,  G01V3/06

CPC classification number: G01V3/06 ,  G01R27/18

Abstract: This invention concerns a device for measuring earth resistance. A constant alternating current is supplied from an inverter to a pair of spaced apart earth probes. Two further probes located between the earth probes are connected to the input stage of an amplifier having a very high input impedance so as to derive a signal which is proportional to the earths resistance. The output of the input amplifier is rectified and fed to a comparator which is also supplied a switched range of reference voltages.

Abstract translation: 本发明涉及测量接地电阻的装置。 恒定的交流电从逆变器提供给一对分开的接地探针。 位于接地探针之间的另外两个探针连接到具有非常高的输入阻抗的放大器的输入级，以便导出与接地电阻成比例的信号。 输入放大器的输出被整流并馈送到比较器，该比较器也被提供给参考电压的切换范围。