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Browse Prior Art Database

Tolerance Compression Decade Panel

IP.com Disclosure Number: IPCOM000092157D
Original Publication Date: 1968-Oct-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Drew, RF: AUTHOR

Abstract

When testing whether resistors on a printed circuit card are within tolerances, a setup such as shown in drawing 1 can be used. Resistors R(y(y))...R(y(n)) are mounted on the printed circuit card. Switches 1 and 3 are ganged together. Switch 1 connects a resistor R(y(m)) to a resistor R(x(m)) equal in numerical value. Connected to the other terminal of resistors R(x(m)) is a voltage source E(0). Connected to switch 1 is the input of operational amplifier 5 whose output is connected both to switch 3 and the input of Deviation From E(0) Detector 7. The output from detector 7 is connected to indicator 9. In operation, detector 7 is set to a given tolerance such that if its input varies from E more than that percentage tolerance, an output is generated and is shown by indicator 9.

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Tolerance Compression Decade Panel

When testing whether resistors on a printed circuit card are within tolerances, a setup such as shown in drawing 1 can be used. Resistors R(y(y))...R(y(n)) are mounted on the printed circuit card. Switches 1 and 3 are ganged together. Switch 1 connects a resistor R(y(m)) to a resistor R(x(m)) equal in numerical value. Connected to the other terminal of resistors R(x(m)) is a voltage source E(0). Connected to switch 1 is the input of operational amplifier 5 whose output is connected both to switch 3 and the input of Deviation From E(0) Detector 7. The output from detector 7 is connected to indicator 9. In operation, detector 7 is set to a given tolerance such that if its input varies from E more than that percentage tolerance, an output is generated and is shown by indicator 9. The input to detector 7 has a value E(0) if resistor R(y(m)) is identical in value to resistor R(y(1)). Switches 1 and 3 are moved serially to insure that it does not vary from the given value by more than the accepted tolerance.

However, unless the tolerance accepted by detector 7 is reset after each individual resistor, all the resistors are tested to the same tolerance. If the device in drawing 2 is incorporated into the device of drawing 1 by mechanically ganging and electrically connecting switches 11 and 13 to switches 1 and 3, each of the individual resistors R(y(m)) can be tested to a different tolerance. Resistors R(p(m)) are selected according to...