circuit 11 from the load 34 is il 1 a voltage drop caused by a flow of the signal current is 1 through the resistor 31 is equal to another voltage drop caused by a flow of the load current il 1 through the resistor 32 il 1 in fig2 is obtained by the following expression that is the current inverter circuit 11 has a current amplification factor k r 1 r 2 fig3 is a circuit diagram showing a second example of the structure of the current inverter circuit according to the present invention this current inverter circuit 12 has one operational amplifier 30 and two resistors 41 and 42 resistance values of the resistors 41 and 42 are respectively r 2 and r 1 this example shows a case where a current source 43 is connected to an input terminal of the current inverter circuit 12 and a load 44 is connected to an output terminal of the current inverter circuit 12 a current flowing into the current inverter circuit 12 from the current source 43 is is 2 and another current flowing into the current inverter circuit 12 from the load 44 is 1 l 2 like in the case of fig2 il 2 in fig3 is obtained by the following expression that is the current inverter circuit 12 has a current amplification factor 1 k r 2 r 1 input impedance of the impedance circuit 1 will be described next in the impedance circuit 1 the amplitude of a current flowing into the current inverter circuit 11 from the passive circuit 10 is.