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Beam Switching Tube Logic Circuit

IP.com Disclosure Number: IPCOM000098341D
Original Publication Date: 1960-Aug-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 3 page(s) / 48K

Publishing Venue

IBM

Related People

Horgan, TB: AUTHOR

Abstract

A ten position beam switching tube performs logical operations based on two or three inputs. The circuitry comprises a full adder.

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Beam Switching Tube Logic Circuit

A ten position beam switching tube performs logical operations based on two or three inputs. The circuitry comprises a full adder.

When the tube 10 is initially turned on, with the spades 11 and the switching grids 12 positive, no beam is formed. If the potential on any spade 11 is lowered, a beam forms from cathode 14 and holds that spade 11 and the associated target 15 down. If the potential of a spade 11 located one, two, three or four positions from the beam is lowered, the beam transfers to this new spade. If the potential of a spade 11, located five to ten positions away is lowered, the beam does not transfer.

The direction of rotation is determined by the direction of a magnetic field applied by a concentric cylindrical magnet (not shown). Lowering the potential of a grid 12 associated with a down spade 11 causes the beam to shift clockwise to the next adjacent spade. Lowering the potential of any other grid 12 has no effect on the beam. Targets 15 are isolated pentode like outputs. Target potentials have no effect on the position of the beam.

The circuit has three input terminals X, Y and CARRY and two output terminals SUM and CARRY. The X terminal 16 is connected to the 2 position spade. The Y terminal 17 is connected to the 4 position spade. The X and Y inputs also are fed through diodes 18 and 19 to pull down the 6 position spade and shift the beam to the 6 position when both inputs are present.

The carry input terminal 20 is connected to the switching grids 12 for positions 0, 2, 4 and 6. A negative level on this input, therefore, lowers the grid potentials and causes shifting of the beam in a clockwise direction to the next adjacent position. The grids 12 for positions 1, 3, 5 and 7 are connected to point 21 thus being maintained at a positive potential. Targets 15 for positions 1, 2 and 4 are connected to the SUM output line 22, causing a negative output level on it when the beam is at one of these positions. Line 22 also connects to the 7 position spade to give an output on line 22, when the beam is at the 7...