They really are "static dissipating" mats. They intentionally have a very high resistance to avoid any significant current flowing through them - much higher than a common DMM can indicate.
Although all of us have seen the sparks that can be produced by static electricity we generate by moving around, those obvious charges are not the most common danger. In many transistors and I.C.s the insulation might be only a few atoms thick, designed to withstand no more than a few volts. Even tiny charges with sufficient voltage can destroy or seriously degrade those devices. So a mat won't protect a board or device laying on it that you suddenly touch while still carrying a big charge yourself, nor will touching the mat instead of touching a ground make you safe. Working at the bench, you will create a static charge much faster by moving around. That's why a wrist strap has a much smaller resistance to ground - usually about 1 megohm - to keep you discharged without producing a shock hazard in the event you touch a live circuit. Even so, I have the long habit of touching the ground terminal directly whenever I'm sitting down at the bench and donning my wrist strap. That way I'm discharged before I ever put the wrist strap on. And, truth to tell, if I'm doing something simple and quick such as reinserting a board in the radio, touching the ground before picking up the board is all I do. Ron AC7AC -----Original Message----- I don't understand how that material is supposed to function, but I tested a piece of it (may have been from some other source) and found that it was not conductive, at least as far as my DVM could measure. I concluded that I could not trust it to drain off any static charge from a workpiece - wrong? Jerry W4UK _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
