| 摘要 |
666,883. Electric resistors. TELEFONAKTIEBOLAGET L. M. ERICSSON. Dec. 3, 1948 [Dec. 4, 1947; Dec. 8, 1947; Dec. 20, 1947], Nos. 31362/48, 31363/48 and 31364/48. Class 37. [Also in Groups XXXV, XXXIX and XL (c)] Rectifiers make use of a conducting element cooled to the region in which its resistance is abruptly changing from its ordinary value to the zero of superconductivity. In this region-a large percentage increase of resistance can be produced either by a slight increase in temperature or by a slight increase in the value of a magnetic field in which the conductor is arranged. Niobium nitrite is mentioned as a suitable substance for the conductor but a metallic conductor such as bismuth or tungsten may be used. As shown in Fig. 7, the cooled conductor is a thin-walled tube 2 and it is brought by the field due to an axially arranged filament 7 carrying direct current to the point at which the half-cycles in the cooled conductor in a direction to aid the field of the filament produce a large increase in resistance and are virtually suppressed. In another system, Fig. 8 (not shown), the working point is controlled by a permanent or electromagnet external to the vessel containing the cooling fluid. Four cooled conductors can be connected as a rectifying bridge which may take the form of a continuous ring, Fig. 13 (not shown). In Fig. 14 (not shown), three tapped rectifiers are used as a three-phase rectifier.
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