| 摘要 |
PURPOSE:To make simple, exact and stable resistance measurement by supplying an AC voltage signal as a constant current, measuring the voltage between two terminals of a body to be measured, detecting the DC component thereof and determining the resistance value of the body to be measured. CONSTITUTION:A square wave AC signal oscillated by an AC oscillation circuit 2 is amplified to a prescribed level by a buffer amplifier 3 and the level below a limit level is taken out by an amplitude limiting circuit 4. The level is returned from a constant current circuit 5 through the resistor 7 to be measured to the circuit 5. The voltage Vx between two terminals of the resistor 7 is, thereupon, measured by a Vx detecting circuit 9 and a half wave rectifying signal 10a' is determined via a half wave DC detecting circuit 10a. The DC component is determined by subjecting this signal to Fourier expansion. The accurate, stable and simple resistance measurement is made by this component and the computation of a constant. |
