conductivity of solder

Discussion in 'General Electronics Chat' started by laduch, Aug 1, 2010.

  1. laduch

    Thread Starter New Member

    Jul 19, 2010
    6
    0
    I made a simple PCB by soldering. I tapped the multimeter probes over the solder line to test the connections using ohm-meter setting, and I found out that the surface of the solder is not very conductive (unless I press the probes into the solder metal). The circuit works though, means the components are connected correctly.
    Is this normal?
     
  2. tom66

    Senior Member

    May 9, 2009
    2,613
    213
    You'll find it difficult to get good contact with solder from the outside. Generally, solder is very conductive.
     
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  3. KMoffett

    AAC Fanatic!

    Dec 19, 2007
    2,574
    230
    The surface of the solder probably was coated with hardened flux, which is non-conductive.

    Ken
     
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  4. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    A general "rule of thumb" is that solder has roughly 5x the resistance of copper.

    There's a chart of resistances of various solder formulas on this page:
    http://www.microwaves101.com/encyclopedia/SolderChart.cfm#chart

    The solder chart references the conductivity of each material to that of copper, which is 1.72 micro-ohm centimeters
     
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