From what I read in the past ESD mats for workbenches should typically consist of two layers:
- A top layer, which is static dissipative (in the MOhm range), to slowly and safely dissipate any charge on components or PCBs
- A bottom layer, which is in the conductive region (kOhm range), to ensure an equally good connection of all parts of the top layer
In our lab we have these double layer mats basically everywhere.
But there are also single layer mats like this one from RS Components:
https://us.rs-online.com/product/rs-pro/7873114/71005298/As far as I can see these single layer mats all are completely in the conductive range and are therefore not safe to handle ESDS components on. A charged component would possibly discharge to fast when touching the mat.
So, wher are these mats used? In which cases are they adequate?