Browse Prior Art Database

Method/Apparatus for Improving Resistance/Capacitance Opens/Shorts Testing

IP.com Disclosure Number: IPCOM000115943D
Original Publication Date: 1995-Jul-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 84K

Publishing Venue

IBM

Related People

Mahlbacher, JC: AUTHOR

Abstract

Disclosed is an alternative method for the detection of defects in circuit boards, using capacitive and resistive measurements via a cable and circuit arrangement.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Method/Apparatus for Improving Resistance/Capacitance Opens/Shorts
Testing

      Disclosed is an alternative method for the detection of defects
in circuit boards, using capacitive and resistive measurements via a
cable and circuit arrangement.

      In prior art, these measurements typically require the use of
both a resistance and capacitance meter, alternately being selected
by a signal multiplexer.

      Detection of defects in circuit boards can be identified
through the use of capacitive and resistive measurements.  These
measurements are made alternatively and typically require the use of
both a resistance and capacitance meter.  The two meters are selected
by use of a signal multiplexer.

      Capacitive measurements are made on circuit boards, and more
generally interconnect devices, to identify shorts.  Resistive
measurements are made to detect opens.  The preferred sequence would
be to position two probes at either end of a segment of a net and to
measure the segment resistance followed by the capacitance of the
network as observed at an arbitrary end of the segment.  The probe
positioning would be done such that all segments were resistance
tested in an order reducing overall positioning time.  With each
resistance measurement to detect opens there would be a corresponding
capacitance measurement for shorts.  The hardware that facilitates
the selection of either a resistance meter or capacitance meter is
referred to as a multiplexor.  Typically the multiplexor is
implemented
with relays and therefore have characteristic switch times and life
expectancy.  The switch time decreases the performance of the test
system
and the life expectancy of the switch requires increased maintenance.

      A capacitance meter such as the KEITHLEY 590CV meter is capable
of obtaining a conductance measurement along with a capacitance
reading.  The conductance is the mathematical reciprocal of the
resistance measured between the inputs of the meter.  By using a
novel cabling configuration the desired resistance/capacitance
readings may be obtained by the single 590 meter eliminating the
multiplex...