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Write In Matrix Circuit

IP.com Disclosure Number: IPCOM000096550D
Original Publication Date: 1963-Jul-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Clapper, GL: AUTHOR

Abstract

The arrangement is for manually inserting symbols and characters into a data processing system. This is by use of a hand-held stylus and a rectangular matrix of elements over which the stylus is passed to generate a character configuration. Each matrix element 3 is formed of conductive material insulated one from the other and each is connected to a circuit similar to the one shown. It comprises a resistance-capacitance integrating network, such as resistor R1 and capacitor C1. C1 has one terminal connected to ground and R1 has one terminal connected to a negative source of potential.

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Write In Matrix Circuit

The arrangement is for manually inserting symbols and characters into a data processing system. This is by use of a hand-held stylus and a rectangular matrix of elements over which the stylus is passed to generate a character configuration. Each matrix element 3 is formed of conductive material insulated one from the other and each is connected to a circuit similar to the one shown. It comprises a resistance-capacitance integrating network, such as resistor R1 and capacitor C1. C1 has one terminal connected to ground and R1 has one terminal connected to a negative source of potential.

The junction of R1 and C1 connects to element 3 and to the input of a bistable device such as a latch. The output of the latch connects to the data processing system and includes an indication lamp LK. The stylus or probe ST has at least the tip or writing portion of it made of conductive material. It connects by a flexible lead and jack J1 to the collector of a PNP transistor. Its emitter connects through resistor R2 to ground. The base of the transistor is biased by a circuit including the diode D1 and resistor R3 connected to a negative source of potential. A constant current, e. g., of the order of one milliampere, is drawn through ST when in contact with one element 3.

The time constant of the integrating circuit connected to each element 3 is selected so that the tip of ST must be in contact with the matrix element for a predetermined time before the ou...