| 摘要 |
PURPOSE:To detect slight current with good accuracy by conducting triangular wave current to the excitation coil of a transformer having primary windings, excitation winding, magnetic flux winding and cancellation current supply winding through which the current to be detected flows. CONSTITUTION:A core 15 is excited by the triangular wave current through a current amplifier 22. The current to be detected is conducted to the primary windings 11P, 11N. The detection winding 14 detects the magnetic flux excited by the triangular wave current and the magnetic flux excited by the current to be detected and takes the current values corresponding to the positive and negative of the magnetic fluxes into sample holding circuits 32, 33. The outputs of the circuits 32, 33 are added 34 and the cancellation winding 42 is excited via an amplifier 42 so that the added value is made zero. The excitation current in this state corresponds to the current to be detected and the value of the current to be detected is determined with good accuracy from said current. |
