Saturday 27 April 2019

power supply - How to know that I am grounded with an anti-static wrist strap?


The resistance of my Belkin anti-static wrist strap shows 0.983, but how do I know that I am grounded by attaching it to computer power supply alone? See the picture below.



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How do I know if that resistance is absorbed by the grounded contact? Must I touch a metal plate below the strap with one lead and power supply with another lead?


UPDATE: I wanted to know if there is a contact between wrist strap and power cable's grounded contact through power supply. Since wrist strap works, i wanted also to know that grounding it to power supply and then connecting to power outlet will work as well so i touched wrist strap's metal plate with one lead and grounding contact of power cable with another lead and saw same resistance as mentioned above. This means that everything works.



Answer



A proper ground strap connection should show 1 to 10 megohms between the part that contacts your skin and the ground terminal of the power cord. This resistance is there to prevent electrocution through the strap.


The point of a ground strap is to dissipate static charge. A large resistor does this slowly enough to not "zap" you, but also doesn't turn you into a large ground rail yourself.


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