| 摘要 |
PURPOSE:To obtain an input/output protective circuit which operates as an effective protective circuit only when an abnormal voltage due to a noise or a surge is applied to an input/output terminal without affecting an influence to a circuit at the time of normal use by providing a section having smaller superconducting critical current than that of other wiring on part or whole of superconducting wiring for connecting input or output terminal to an internal circuit. CONSTITUTION:A protective circuit is formed of a normal superconducting wiring 2 used also in an electrode pad 1 circuit made of a superconducting wiring, the pad 1, and a superconductor 3 having smaller critical current than that of the superconductor of the wiring 2. The superconductor 3 holds a superconducting state by a current of the degree flowing to a normal circuit, and so selected for its material, manufacturing method and shape as to conduct a normal conduction transfer by a current lower than the degree in which an internal circuit is damaged. With this configuration, since the pad to the circuit is all wired with the superconductor at the time or normal use, the protective circuit does not affect the influence to the circuit, and when a large current is input, the superconductor 3 causes a normal conduction transfer to become a resistor, thereby alleviating an excess current. That is, it operates as the function of the protecting circuit which operates only when the excess current is input.
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