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Can an ESD mat be tested without special tools?

baldengineer

There are inexpensive continuity testers that let you verify a loop between you, your wrist strap, and ground.

 

Without investing into special weights (probes), is there an effective way to measure an ESD mat’s resistance? Or more simply, verify areas of an ESD mat are still effective?

 

Can it be done with “just” a multimeter and a power supply?

Parents

  • I've tried it with the two kinds of mat I have. This is with 10V from a bench PSU and my 5.5 digit Fluke meter (I also put a 100 ohm resistor in series, in case I touched the probes together, though I  realised after that I could have just used the current limit on the PSU).

     

    Cheap, black, rubbery mat.

     

    a reading over a distance of 10mm of around 8uA

     

    Old, blue, 'Farnell' branded mat

     

    maybe something like 3nA (this is right down near the limits of what this particular meter will read)

     

    Neither is really a resistance. There isn't too much variation with distance.

     

    On a cheap handheld meter, the black one reads about half a megaohm. The probes are more pointed and dig into the surface a bit which is probably why it's less than the 10V/8u reading would suggest (1.25M).

    The professional blue one is over-range.

     

    The 3nA figure for the Farnell mat sort of suggests a rough equivalent resistance of 3.33  G ohms but it could be quite a bit different to that (the meter reads 2nA with the probes in mid air and the reading goes up to 5nA on the mat, so I'm not all that confident in it).

     

    Edited because somehow I stupidly wrote Tera rather than Giga.

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  • I've tried it with the two kinds of mat I have. This is with 10V from a bench PSU and my 5.5 digit Fluke meter (I also put a 100 ohm resistor in series, in case I touched the probes together, though I  realised after that I could have just used the current limit on the PSU).

     

    Cheap, black, rubbery mat.

     

    a reading over a distance of 10mm of around 8uA

     

    Old, blue, 'Farnell' branded mat

     

    maybe something like 3nA (this is right down near the limits of what this particular meter will read)

     

    Neither is really a resistance. There isn't too much variation with distance.

     

    On a cheap handheld meter, the black one reads about half a megaohm. The probes are more pointed and dig into the surface a bit which is probably why it's less than the 10V/8u reading would suggest (1.25M).

    The professional blue one is over-range.

     

    The 3nA figure for the Farnell mat sort of suggests a rough equivalent resistance of 3.33  G ohms but it could be quite a bit different to that (the meter reads 2nA with the probes in mid air and the reading goes up to 5nA on the mat, so I'm not all that confident in it).

     

    Edited because somehow I stupidly wrote Tera rather than Giga.

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