Patent US 4,149,097

A waveform transition sensitive Josephson junction circuit having sense bus and logic applications is disclosed. In a preferred embodiment, a device capable of carrying Josephson current is shunted by a utilization circuit. Current flowing in the device is diverted to the utilization circuit in response to only one of a pair of transitions of a pulsed input applied to the device. On one transition of the applied pulsed input current, a current is induced in a current path which follows the input until the threshold of a switchable device in the current path is exceeded. The switchable device switches and the induced current drops to zero. If the current generated by the transition is in the opposite direction to current in the Josephson device, the Josephson device remains in its unswitched state. On the other transition of the pulsed input, the induced current follows the input and appears as an oppositely directed current in the Josephson device causing it to switch and deliver current to the utilization circuit. The switching of the switchable device when its threshold is exceeded reduces the induced current to zero. The current applied to the Josephson device and the input applied thereto may both be derived from pulsed sources with the Josephson devices of the circuit operating in latching or self-resetting modes.