How a surface resistance and resistivity tester works?
This is a megohmmeter, normally a digital instrument with a LCD display or a display of LEDs at different surface resistance and resistivity ranges, the latter covering de conductive eg 10E2 to10E4, the antistatic dissipative eg 10E5 to 10E11, and insulating ranges over 10E11. Typically the meter is used to measure resistance in between a test point on the surface to ground (RTG), between two test points on the surface (RTT) [these measurements must comply with EOS/ESD-S4.1]. The measuring of resistance from a surface point to ground is done by using a clip probe, or something similar, as to connect to ground and a special surface probe which facilitates the connection of the second electrode (this is a 5 pounds cylindrical weight treated with conductive material like carbon). The measurement of resistance in between two surface to surface points is done with two of the above mentioned special probes. Resistivity on flat homogeneous surfaces (also on multilayered surfaces noting RH and
