| 摘要 |
<p>PURPOSE:To obtain a device which is used for both AC and DC currents and transforms even a fine current with high precision by providing the 1st - the 4th windings, etc. CONSTITUTION:A transformer 1, a magnetic flux detecting circuit 4, a current amplifier 7, etc., are provided. The transformer 1 is constituted by providing primary winding 11, secondary winding 12, tertiary winding 13, and quadratic winding 14 around a core 15. The voltage induced across the winding 14 when a current I1 to be detected is zero is based upon an exciting current Iex and magnetism characteristics of the core 15, so the magnetism characteristic curve of the core 15 is symmetric between a plus and a minus side. The induced voltage of the winding 14 is also symmetric between a plus and a minus side and the asymmetric detection output of the circuit 4 is zero. When the current I1 is not zero, the core 15 is biased according to the level of the current. Consequently, positive and negative crest values of the voltage induced across the winding 14 are different. Therefore, when only a positive and a negative voltage whose amplitude are larger than some value are considered, it is known how the core 15 is biased by the current I1. For the purpose, a current I2 is flowed to the winding 12 by using an amplifier 7 so that the bias of the core 15 is zero, and then the level and polarity of the current I1 are known.</p> |
