Model 4431T Shielded Bag Test System - Operating Manual
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D00003 Rev. K.
APPENDIX A – Waveform Verification
AA.1 Test Waveform considerations
ANSI/ESD STM11.31 requires verification of the discharge current pulse both through a short to ground
and through a 500 Ohm resistor. This requirement is based on a test apparatus where the Discharge
Simulator and the electrode assemblies are separate components. The Model 4431-T is an integrated
system where the discharge waveform at the discharge electrode is designed and set up at the factory to
meet the specified requirement. This section provides instructions for verification of the energy pulse
using the built-in components of the system, and using external independent measurement equipment.
AA.2 Waveform verification using the 4431-T built-in components.
Waveform energy and peak current are verified automatically prior to each test series in Automatic
mode. To perform verification testing in Manual mode, measurement of the waveform may be
performed with the built-in capacitive sensor, CT-1 current sensor, and 500 Ohm resistor. This
measurement is performed by simply discharging directly to the capacitive sensor with no sample in
place and the latch closed. This waveform is shown in Figure 11-1 and should have a peak value of
approximately 500 milliamps and have an energy of 50,000 +3,000 nanoJoules at a 1,000 Volt
discharge. Adjust the VOLTS control on the 4431 Discharge Unit to bring the energy reading within
range.
Fig. AA-1. Calibration Waveform
