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Cryogenic Read-Write Circuit

IP.com Disclosure Number: IPCOM000098949D
Original Publication Date: 1962-Feb-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Beesley, JP: AUTHOR

Abstract

A cryogenic read-write circuit drives other cryotrons or is driven by cryotrons. Two versions, A and B, of such circuit are shown.

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Cryogenic Read-Write Circuit

A cryogenic read-write circuit drives other cryotrons or is driven by cryotrons. Two versions, A and B, of such circuit are shown.

In A, rectangles 2 and 4 are the gates of two cryotrons and drive lines 6 and 8 are their respective control windings. Closed loop D is the path taken by persistent currents. Assuming that a write 1 is desired, the Z and Y lines are actuated. The resultant resistive state of gate 4 causes Z current to pass through gate 2 and be diverted along line 10, control line 12, line 14, and to a sink along line 16. When Y current terminates, Z current is withdrawn and persistent current D, representative of a 1 storage, circulates.

The writing of a 0 occurs when Y current appears without Z current. No persistent current is stored and no previous persistent current is destroyed. Reading occurs when X current and Z current are pulsed simultaneously. X current, alone, is insufficient to drive gate 2 resistive. The presence of persistent current D, added to read current X, drives gate 2 resistive, diverting Z along line 18 to an indicating circuit. If a 0 were stored (no persistent current D), then when X current appears, cryotron 2 remains superconductive, and a 0 readout appears on line 16.

In B to write a 1 Y and Z are pulsed, driving cryotron 4 resistive, diverting Z along path 10 12 14 16. Termination of Y, followed by removal of Z, causes a persistent current D to flow through gate 4 and act as control current for...