| 摘要 |
PURPOSE:To attain current/voltage conversion almost without errors in case of the current measurement of the primary conductor in a wide range by changing load resistance in accordance with the size of the primary current value. CONSTITUTION:One of the secondary winding of a current transformer 2 is connected to a zero potential line and the other to a common terminal K1 of an alteration switch 5a. The switching terminal L1 of the switch 5a is inputted to the negative input terminal of an amplifier 6a and terminals M1, N1 are inputted to the positive input terminal of an amplifier 6. A common terminal K2 and a terminal L2 of an alteration switch 5b are connected to the positive input terminal of the amplifier 6 and the output terminal of the amplifier 6a respectively and terminals M2, N2 are connected to a zero potential line through load resistors 4b, 4c respectively. The negative input terminal of the amplifier 6 is connected to the zero potential line through a resistor 7 and to its output terminal through a resistor 8 respectively and the negative input terminal of the amplifier 6a is connected to its output terminal through a resistor 9 and the positive input terminal is directly connected to the zero potential line respectively. The load resistors 4b, 4c are selected in accordance with the current value of the primary conductor 1. |
