ANSI STM11.31-2012 pdf download For Evaluating the Performance of Electrostatic Discharge Shielding Materials – Bags
5.2 Waveform Verification Equipment Equipment capable of verifying the pulse waveforms defined in this standard shall include but is not limited to: a storage oscilloscope, a high voltage resistor and a suitable current probe.
5.2.1 Oscilloscope A digital storage oscilloscope capable of a 200 MHz single shot bandwidth and a minimum sampling rate of 500 mega samples per second.
5.2.2 Current Probe The current probe shall have a minimum frequency response of 500 MHz. (Included in the current probes that meet this requirement are a Tektronix CT-1, CT-2 and CT-6.) The maximum cable length is 1 meter.
5.2.3 High Voltage Resistor The resistor shall be a 500 ohm, 1% tolerance, 1000 volt, low inductance, sputtered metal film (Caddock Industries type MG or equivalent).
5.3 Capacitive Probe A parallel plate capacitive probe shall be constructed per Figure 2. The capacitance for the probe shall be 8 pF 2 pF. The probe capacitance can be verified per Section 7.0 (C). The spacer between the plates shall be made of an insulating material such as polycarbonate or acrylic.
5.4 Discharge Electrode and Ground Electrode The discharge electrode and the ground electrode shall be 3.8 0.025 cm (1.5 0.010 inches) in diameter and shall be made of a conductive material. The support area that surrounds the ground electrode should be 20 x 25 cm (8 x 10 inches) and have a surface resistivity greater than 1 x 10 13 ohms per square as measured per ASTM D 257.
5.5 Bag Size The bags used for this test should be 20 x 25 cm (8 x 10 inches), with 20 cm (8 inches) being the open end. NOTE: If other bag sizes are used, care must be taken to ensure that the same size bag is used to provide consistent and fair comparison of bags from various manufacturers. Bags, which are not large enough to have the capacitive probe completely inside the bag may yield erroneous results. Bags with substantial differences in thickness may yield results that do not correlate due to the increased transmission length through the bag.
5.6 Computer / Software A computer should be used to analyze the data that is acquired by the oscilloscope. A generic description of the analysis system is described in Annex A.
ANSI STM11.31-2012 pdf download
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