VARIABLE RESISTOR CIRCUIT

PURPOSE:To vary the resistance of a resistance circuit by means of a simple circuit by connecting plural superconduction substances with difference critical temperature in series and varying the temperature. CONSTITUTION:The resistance of a resistor circuit comprising superconduction substances 1-3 is varied by varying the temperature in the superconduction substances 1-3 whose critical temperature differs. The base voltage of a transistor(TR) 5 divided by a base-emitter of TRs 5, 6, that is, a voltage given to a current source is controlled by the resistance circuit and an ion injection resistor 4 to adjust the current of a constant current source. Moreover, as the superconduction substances used in the circuit, a substance whose resistance is zero in the superconduction state such as a chemical compound of Nb-Sn, an alloy of Nb-Ti, a ceramics of Y-Ba-Cu-O or Sr-Ba-Y-Cu-O or other organic superconduction substance is used.