JPS6319281U - - Google Patents

Description

[Brief explanation of the drawing]

Fig. 1 is a connection diagram showing one embodiment of this invention, Figs. 2 and 3 are connection diagrams for explaining other embodiments of this invention, and Fig. 4 shows a conventional voltage applied current measuring device. FIG. 5 is a connection diagram for explaining the equivalent circuit of the voltage feedback circuit in a conventional device. FIGS. 6 and 7 are connection diagrams for explaining the connection structure of the conventional guard voltage applying means. The connection diagram and FIG. 8 are waveform diagrams for explaining the operation of the conventional voltage applied current measuring device. 100: Subject, 200: Voltage supply source, 300
: Current measuring means, 304: Range switching means, 40
0: cable, 401: voltage supply source, 402: voltage detection line, 403: shield, Ra: leak resistance, Ca: capacitance, 500: voltage feedback circuit, 60
0: common potential point, 700: guard voltage application means,
800: Switching means.

Claims (1)

[Scope of Claim for Utility Model Registration] A. A voltage supply source that applies voltage to the terminals of the test object via a voltage supply line; B. The terminal voltage of the test object is extracted through a voltage detection line and returned to the voltage supply source, A voltage feedback circuit for maintaining the terminal voltage of the test object at a desired voltage, C. A current measuring means for measuring the current flowing through the test object through the voltage supply source, and D. E a guard voltage applying means that applies the same voltage as the voltage applied to the voltage supply line to a shield that protects the voltage supply line and the voltage detection line; A voltage applied current measuring device comprising: switching means for applying a voltage at a common potential point to the guard voltage applying means in conjunction with switching to the guard voltage applying means.