Browse Prior Art Database

Automatic Resistor Testing

IP.com Disclosure Number: IPCOM000093755D
Original Publication Date: 1966-Feb-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Malaccorto, AE: AUTHOR [+2]

Abstract

Bridge circuit 10 is used in conjunction with computer 12 to evaluate resistance parameters of electrical components. Bridge resistors 14, 16 and 18 are adjustable by the computer program. They can be selected to adjust bridge 10 for either the desired resolution or accuracy and power dissipation across component 20 being evaluated. Resistors 22 and 24 null imbalances due to lead resistance and connection to component 20. The values of resistors 22 and 24 are also under computer control. Similarly, resistor 26 is computer-controlled. It is used for fine bridge excitation voltage adjustments. Coarse voltage selection is obtained through computer-adjustable power supply 28.

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Automatic Resistor Testing

Bridge circuit 10 is used in conjunction with computer 12 to evaluate resistance parameters of electrical components. Bridge resistors 14, 16 and 18 are adjustable by the computer program. They can be selected to adjust bridge 10 for either the desired resolution or accuracy and power dissipation across component 20 being evaluated. Resistors 22 and 24 null imbalances due to lead resistance and connection to component 20. The values of resistors 22 and 24 are also under computer control. Similarly, resistor 26 is computer-controlled. It is used for fine bridge excitation voltage adjustments. Coarse voltage selection is obtained through computer-adjustable power supply 28.

In operation, bridge 10 is computer-adjusted so that the null condition exists at an expected nominal resistance value for component 20. Bridge ratios are programmed as required for the desired accuracy. The magnitude of the expected deviations of the unknown resistance from its nominal value is a factor in setting up bridge 10. Computer controlled multiplexing, via multiplexer 30, of component 20 into bridge 10 generates an error voltage E across bridge 10. Multiplexer 30 is controlled so that component 20 is connected to bridge 10 for a predetermined time, thus minimizing, and holding constant, errors due to self- heating on bridge components and component 20. Error voltage E is digitized by analog-to-digital converter 32 and stored for analysis by computer 12. The l...