Typical Electrostatic Voltage Levels - HP Compaq NX4820 Maintenance And Service Manual

Removal and Replacement Preliminaries
Table 4-1 shows how humidity affects the electrostatic voltage
levels generated by different activities.
Event
Walking across carpet
Walking across vinyl floor
Motions of bench worker
Removing DIPS from plastic tube
Removing DIPS from vinyl tray
Removing DIPS from Styrofoam
Removing bubble pack from PCB
Packing PCBs in foam-lined box
✎
A product can be degraded by as little as 700 V.
Table 4-2 lists the shielding protection provided by antistatic
bags and floor mats.
Material
Antistatic plastic
Carbon-loaded plastic
Metallized laminate
4–8

Typical Electrostatic Voltage Levels

Static-Shielding Materials
Use
Bags
Floor mats
Floor mats
Table 4-1
10%
35,000 V
12,000 V
6,000 V
2,000 V
11,500 V
14,500 V
26,500 V
21,000 V
Table 4-2
Voltage Protection Level
1,500 V
7,500 V
5,000 V
Maintenance and Service Guide
Relative Humidity
40%
15,000 V
5,000 V
800 V
700 V
4,000 V
5,000 V
20,000 V
11,000 V
55%
7,500 V
3,000 V
400 V
400 V
2,000 V
3,500 V
7,000 V
5,000 V