The invention relates to a device for measuring current in an inductor and being connected in parallel with said inductor. The device includes a network in parallel with the inductor and connected to the terminals A and B comprising a resistor R2 in series with a resistor R1 in parallel with a capacitor...http://www.google.com.tw/patents/US7394264?utm_source=gb-gplus-share專利 US7394264 - Device for non-dissipative measurement of the current in an inductor
