| 摘要 |
911,371. Superconductor circuits. INTERNATIONAL BUSINESS MACHINES CORPORATION. Feb. 2, 1959 [Feb. 3, 1958], No. 3676/59. Class 40 (9). [Also in Group XXXVI] A superconductive element G is used in a current indicator. The element G is connected in series with a feed-back coil C 2 which tends to drive the element into a resistive state. A superconducting control coil C 1 also tends to drive the element towards a resistive state when it is fed with a current to be measured. Initially the voltage source is adjusted so that the element G operates somewhere, on the transmission characteristic (Fig. 1b) between zero resistance and normal resistance. When a current is applied to coil C 1 , the resistance of the element G is affected and more or less current flows in coil C 2 . The current indicator I is calibrated to indicate the current in C 1 . The arrangement may be used in a bridge (Fig. 3, not shown) to produce a voltage as a measure of the current in coil C 1 . In Fig. 2, the voltage drop across superconductive element G indicates the current in primary coil C 1 of transformer T. The element G is biased to the middle of the characteristic by means of a voltage source V 1 and a variable resistor R 1 . The transformer windings C 1 , L 1 and the winding C 2 on the element G are all superconductive. Even a constant current in coil C 1 induces a current in coils L 1 , L 2 sufficient to neutralize the flux introduced by C 1 . In a further modification, Fig. 4, the feed-back coil C 2 is driven by an NPN transistor controlled by the volt drop across element G. A meter M in the feed-back circuit indicates the current in coil C 2 .
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