Browse Prior Art Database

Josephson Not Circuit

IP.com Disclosure Number: IPCOM000077918D
Original Publication Date: 1972-Oct-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Herrell, DJ: AUTHOR [+2]

Abstract

Use is made of an excessively damped Josephson junction device (with no hysteresis) which is held in a dissipative quiescent state, either continually or by clock pulses for the proper cycle to provide the output function W = A whenever the input function A is applied.

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Josephson Not Circuit

Use is made of an excessively damped Josephson junction device (with no hysteresis) which is held in a dissipative quiescent state, either continually or by clock pulses for the proper cycle to provide the output function W = A whenever the input function A is applied.

The nonlinear I-V characteristic of a highly damped Josephson junction device is illustrated in Fig. 1. This characteristic is dependent upon the amplitude of the magnetic bias field applied and moves vertically as this field is changed. By application of an external DC bias current, the junction can be quiescently biased in a V not= 0 state with no input signal (A) present. The direction of input current signal to be inverted is chosen such that its field opposes that produced by the DC bias current, as shown in Fig. 2. Thus, with an input on the A line, the junction operates in the V = 0 state, whereas when A = 0, the junction operates in the V not = 0 state.

The DC bias field can be supplied by feedback of the gate current, or it can be set up in a superconducting ring at an initial cool to 4.2 degrees Kelvin. If desirable, instead of a steady state magnetic bias, this bias may be clocked and applied prior to signal input to line A.

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