Alex,
Amendment 2:2001 to EN 61000-4-2:1995 (same as Amendment A2:2000 to IEC
61000-4-2:1995) calls for discharging ungrounded equipment, or
ungrounded part(s) of equipment between ESD zaps. You use a bleeder
cable with 470k resistors at both ends, connected to the horizontal
coupling plane for
Amendment 2 to IEC 61000-4-2:1995 specifically addresses the test method
for ungrounded equipment. Refer to section 7.1.3 of that standard. To
answer your first question, yes the charge applied to the product should be
discharged before applying the next discharge. Regarding your follow up
Dear Alex McNeil,
The intend of the standard is that each discharge is an individual
event. This means:
Electromagnetic consequence
===
All charges need to be drained before the next discharge is applied. You
may use an Ionizer, a conductive brush, a ground wire etc. to
Alex,
The new A2 (Feb 2001) of EN61000-4-2:1995 is very clear on this point.
Paragraph 7.1.3 states the charge on the EUT shall be removed prior to
each applied ESD pulse. I think this would take care of the problem you are
seeing with the charge reversal that you talk about in question 2.
Dan
Most labs I have ever worked with return the EUT to a neutral level prior
to applying opposite polarity discharges, which means use a wire attached to
reference ground to short out any accumulated charge. However this has
usually been with air discharge to non-conductive surfaces such as an
5 matches
Mail list logo
