公开(公告)号：JPS6035274A

公开(公告)日：1985-02-23

申请号：JP14410583

申请日：1983-08-05

Applicant: TOA ELECTRONICS

Inventor： SHIMADA KOUICHI ,  ISHIKAWA KIYOU ,  EMORI KEIZOU ,  SATOU TOMOAKI

IPC: G01R19/15

Abstract: PURPOSE:To enables the measurement of fine current using a relatively long cable by connecting a detection resistor between the inversion input terminal and the output terminal of a differential amplifier, one end of an object to be measured to the inversion input terminal and the other end of the object to the output terminal through the power source. CONSTITUTION:A differential amplifier 17 with a high gain and non-saturable is used. The non-inversion input terminal is grounded and a detection resistor 13 is connected between the inversion input terminal and the output terminal thereof. One end of an object 11 to be measured is connected to the inversion input terminal while the other end of the object 11 is connected to the output terminal through the power source 12. With such an arrangement, with the feedback action through the detection resistor 13, the inversion input terminal has almost the ground potential. The current I1 flowing through the object 11 to be measured runs to the detection resistor 13 and the product RsI1 of the current I1 and the resistance value Rs of the detection resistor 13 is measured with a voltometer 18 to determine the current I1.