I'm in the process of putting together a little electroncis lab and thought it would be good practice to have a rubber ESD mat to protect my devices from ESD and my desk from solder. I bought and finally received
this cheap mat from an eBay seller in Hong Kong. The specs on the eBay listing are given as:
Surface: resistance: 107-9?, color: green, gloss material
Bottom: resistance: 103-5?, color: black
I parsed that typography as 10^7 - 10^9? for the top, and 10^3 to 10^5? for the bottom.
I don't have a megger and my DMM has a maximum range of 50M? (no siemens range), and I live in a dry climate, so I'm not surprised I can't measure any resistance on the green top of the mat. However, if the bottom is really as conductive as the description suggests (100K?), I'd definitely expect to be able to measure it. But no matter where I measure or how hard I press with pointy probes, I get a measurement of infinite resistance.
My question: Am I measuring incorrectly, or did I buy a mat that's not suitable for ESD dissipation? It's not even very important that I have one (I tested this cheap one with my soldering iron, and it
is heat resistant at least), but I'd feel sort of silly plugging my wrist strap into some completely insulating piece of rubber and thinking I had an ESD mat just because the eBay description claimed it was.
I found this thread from last year which has some useful information, but I'd still be interested in anyone's opinion or whether anyone has had experience with "fake" ESD work mats before:
https://www.eevblog.com/forum/beginners/esd-mat-selection-guidelines-help-please/