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Matrix Resistance Measurement

IP.com Disclosure Number: IPCOM000075386D
Original Publication Date: 1971-Sep-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 3 page(s) / 58K

Publishing Venue

IBM

Related People

Olsen, FW: AUTHOR

Abstract

This matrix resistance measurement technique can provide an inexpensive solution to the resistance measuring requirements of large electronic circuit boards. The technique utilizes a matrix of special cells which enables the measuring of resistance from any node to any other node.

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Matrix Resistance Measurement

This matrix resistance measurement technique can provide an inexpensive solution to the resistance measuring requirements of large electronic circuit boards. The technique utilizes a matrix of special cells which enables the measuring of resistance from any node to any other node.

The cell may consist of a latching power device (to serve as a driver if node is selected as such) such as a SCR, with an X and Y - addressing for test condition drive and SCR gate set "on" inhibit, and with a means of holding the latching power device "on". The diodes D1, D2, D3 and D4 provide the ability to supply hold current for a fired SCR from either X or Y lines and this allows sequential addressing of all nodes, while maintaining hold current on the one fired SCR. The matrix may be controlled by an X and Y-addressing scheme, which may consist of a clocked X and Y-counter and an X and Y-multiplexer for the voltmeter output.

The X and Y axis of the test cell array are interchangeable and may be operated in the following manner: 1) The X and Y axes have two driver voltage levels and a sense current preload, which are +V (the test voltage) and -2 volts (the hold-off gate) with a sense current preload of about 0.001 of the current used in the network under test. Hold all X and Y axes lines at -2 volts. 2) Select a node as a driver by the following method: (a) Bring up a +V on the Y axis of the selected coordinate. (b) Allow the selected coordinate's X axis to be released from -2 volts which allows the preload to operate. (c) Bring up a + voltage (logic level) on the SET buss so that the SCR may fire. (d) Return the voltage on the SET buss to -2 volts. The voltage that is present on the selected X axis is the voltage present at the driving node and also the anode-to-cathode drop of the driving SCR. 3) Testing of the nodes can be executed sequentially in the following m...