Abstract: A logic circuit device includes a superconductive body formed of a ceramic superconductive material. The ceramic superconductive material has random grain boundaries which act as weak couplings. The ceramic superconductive material also has a magneto-resistive property. There is at least one conductor arranged near the ceramic superconductive body in order to exert a magnetic field on the ceramic superconductive body. The ceramic superconductive body changes its resistance in response to the magnetic field generated by the conductor. The ceramic superconductive body can be used as part of a logic circuit.

Abstract: A superconducting threshold logic circuit comprises current switching circuits each having a Josephson device. Bias currents of the switching circuits are varied independently to change weights for input signals. A sum of the weighted input signals are inputted to another current switching circuit having a Josephson device in order to compare the sum with a threshold.

Abstract: A superconducting circuit comprises a quantum flux parametron. In the superconducting circuit, at least one of two Josephson devices is a voltage controlled superconducting device, the critical current of which can be controlled by applying a voltage. By adjusting the applied voltage, the critical currents of the two Josephson devices can be equalized. If an input signal is used as the applied voltage, the input signal can be isolated from an output signal. And further, if both critical currents of the two Josephson devices are increased after an input signal is supplied, the input signal can be stably amplified.

Abstract: This is a superconducting digital logic amplifier for interfacing superconductor circuits with semiconductor circuits. It provides a gigahertz amplifier to convert low voltage superconducting logic signals to higher voltage signals, suitable for semiconductor signal processing circuits. It may, for example, provide a factor of ten voltage gain to raise the 2.5 mV Josephson logic signals of conventional metallic superconductor circuitry to 25 mV signals for input into inexpensive semiconductor amplifiers which, in turn, can power semiconductor logic circuitry. Generally, it utilizes a first series string of Josephson junctions in series with an input Josephson junction to provide a series combination which is then connected in parallel with a second string of higher critical current Josephson junctions. The input signal is introduced between the first series string and the input Josephson junction, and the output terminal is connected at the common connection opposite the input Josephson junction.