Manually-operated continuity/shorts test probe for bare interconnection packages
US5256975A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 1, 1992 |
| Grant date | Oct 26, 1993 |
| Priority date | — |
| Expiry date | Jun 1, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R31/312
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A hand-held test probe is employed which uses a capacitance measuring circuit to measure capacitance as the probe is scanned along a pattern of conductors (pads or pins) at a steady rate. The capacitance measurement is stored in a memory during the scan, then maximums are detected in the stored data, corresponding to the conductor pattern. If a particular conductor has a short or a break in continuity, its capacitance will be more or less than it should be. The detected maximums are compared with recorded values for a known-good printed wiring board for this scan pattern. If the comparison shows a difference greater than a selected threshold, an error is indicated for this pin location. The known-good is scanned in a "learn" mode, in which the capacitance values are stored for each scan, identified by scan number.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.