发明名称 |
Method and circuit for testing the conductive circuitry of a printed circuit board |
摘要 |
The reliability of conductive circuitry of a printed circuit board and particularly the integrity of the conductive barrels of the through-holes is tested by cyclically passing a current through a plurality of interconnected barrels. The current must be sufficient to resistively heat the conductive barrels to a temperature at which the glass epoxy substrate adjacent to each barrel reaches a transition temperature at which the glass epoxy changes state from a solid to a semi-solid. After sufficiently heating the glass epoxy, it is allowed to cool to ambient temperature. This cycle is repeated for a predetermined number of cycles and the resistance of the barrels is measured after each cycle. A measured resistance that exceeds a predetermined value indicates that one or more defects is present in the interconnected barrels.
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申请公布号 |
US5172063(A) |
申请公布日期 |
1992.12.15 |
申请号 |
US19910704522 |
申请日期 |
1991.05.23 |
申请人 |
NORTHERN TELECOM LIMITED |
发明人 |
MUNIKOTI, RAMACHANDRA;DHAR, PULAK |
分类号 |
G01R31/28 |
主分类号 |
G01R31/28 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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