| 摘要 |
PURPOSE:To obtain a resistance which is not influenced by a variation portion of an IC internal resistance by connecting a buffer amplifier between an input and an output, in a circuit constituted so as to obtain a current being proportional to a potential difference between two points. CONSTITUTION:A voltage of a point P1 and a voltage of a point P2 are inputted to an operation amplifier 50 in which an input impedance, an output impdedance, and a gain are 2(R+re),<infinity>, and (gm), respectively, so that an output can be obtained from point P3, P4. According to this circuit constitution, the circuit whose gain (gm) is not influenced by a dispersion of an internal resistance of an Ic is obtained. However, when it remains as it is, it does not become a resistance, therefore, ideal buffers 51, 52 are connected between the input and output points P1, P3, and between P2, P4, respectively. As a result, a current (i)=gmX(potential difference between P1, P2) being proportional to the potential difference between the points P1, P2 flows in from the point P3, and flows out of the point P4. In this way, even if a dispersion is generated in the intenal resistance of the IC, a stable IC-converted resistance can be obtained. |
