ESD CORNER
ESD Systems’ ESD Technical Newsletter
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A listing of materials, with respect to the polarity and magnitude of charge generated during contact and separation is called the Triboelectric Series. The series is arranged so that those materials at the top of the list lose electrons and charge positively when rubbed with materials below them relative to the Series. Conversely, the materials at the bottom of the list gain electrons and charges negatively. The farther away the materials are from each other within the list, the greater the magnitude of the charge is generation by them under tribocharging conditions.
The series should be considered a guide to both polarity and relative charge magnitude for various materials. Frequently, one finds some slight inconsistencies in magnitude between two materials from what the Series indicates. Sometimes complete reversals of material positions have been observed.
Table 1 TYPICAL ELECTROSTATIC VOLTAGES* |
|||
EVENT |
RELATIVE HUMIDITY |
||
10% |
40% |
55% |
|
Walking across carpet |
35,000 |
15,000 |
7,500 |
Walking across vinyl floor |
12,000 |
5,000 |
3,000 |
Motions of bench worker |
6,000 |
800 |
400 |
Remove DIPs from plastic tubes |
2,000 |
700 |
400 |
Remove DIPs from vinyl trays |
11,500 |
4,000 |
2,000 |
Remove DIPs from Styrofoam |
14,500 |
5,000 |
3,500 |
Remove bubble pack from PCBs |
26,000 |
20,000 |
7,000 |
Pack PCBs in foam-lined box |
21,000 |
11,000 |
5,500 |
*Source: AT&T ESD Control Handbook-1989
Click below to link to our Triboelectric Series Chart.
Copyright © Desco Industries, Inc. 1999
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