ANSI ESD STM11.12-2000 pdf free.Volume Resistance Measurement of Static Dissipative Planar Materials.
7.0 Apparatus
The equipment used for volume resistance measurements of static dissipative material Is described below
7.1 Electrode Assembly
The electrode assembly consists of: A top electrode and a bottom electrode, See Figure 1 for System setup
7.1.1 Top Electrode
The top electrode assembly consists of two concentric rings which make contact with the material under test See Figure 2
The contact surface material of the electrode
assembly shall be conductive rubber having a
hardness of 50 to 70 on the Shore-A Durometer
scale arid a volume resistivity of less than 10
ohm-cm per ASTM 0-991
The inner electrode shall be a solid disk 1.2+
0025 inches (30.48 + 0.64mm) in diameter.
The inner electrode shall be flat and make total
contact with the test sample.
The outer electrode shall be a ring having an
inner diameter of 2.25 + 0.025 inches (57.15 ±
0.64mm). The width of the outer ring shall be
0.125 + 0010 inches (3.18 + 0.025mm)
The total weight of the top electrode assembly shall be five (5) pounds, + 2 ounces (2.27 kg, + 56.7 grams).
7.1.2 Bottom Electrode Sup port
The bottom electrode shall be a flat conductive metal plate sufficiently large to support the sample under test. The plate should be supported by an insulative material having a surface resistivity greater than 1 x 1012 ohm/square per ASTM D-257. See Figure 3.
7.2 instrumentation
The instrumentation may consist of either a power supply and a current meter (ammeter) or an integrated instrument that combines these functions The power supply or instruments open circuit voltage shall be 10 0.5 volts and 100 + 5 volts. The resistance measuring instrument shall be capable of measuring from 2 x lO4to5x 10’2ohms.
10.0 Upper Resistance Range System Verification Procedure: The following procedure is used to determine the maximum electrification time and the ability of the system to measure resistances up to 1 x 10 ohms. This is done at 12% RH and 72 degrees F. A) Connect the electrode assembly to the instrument according to Figure 6. B) Insert the high resistance verification fixture into the electrode assembly. C) Apply a voltage of 100 volts to the electrode assembly and wait for the reading to stabilize. Record the stabilized resistance value and the time required to stabilize. This value should be within + 5% of the certified resistance value of high resistance verification fixture. Turn off the applied voltage. D) Repeat step C for a total of five (5) times and record the time required for the instrumentation to indicate the resistance. E) The Electrification Period shall be the average of the five readings recorded in steps C and D plus 5 seconds.ANSI ESD STM11.12 pdf download.