Compaq Presario 17XL Presario NA1700XL Series Maintenance and Service Guide - Page 81

Electrostatic Discharge, Generating Static

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Presario 1700 Series Models: XL260, XL261, XL262, XL264, XL265, XL266, XL274, XL275, XL360, XL361, XL362, XL363, XL364, XL365, XL366, XL367, XL368, XL369, XL370, XL371, XL372, XL373, XL374, XL375, XL376, XL377, and XL378 Electrostatic Discharge A sudden discharge of static electricity from a finger or other conductor can destroy static-sensitive devices or microcircuitry. Often the spark is neither felt nor heard, but damage occurs. An electronic device exposed to electrostatic discharge (ESD) may work perfectly throughout a normal cycle and may not seem to be affected at all. However, although it may function normally for a while, it may be degraded in the internal layers, reducing its life expectancy. Networks built into many integrated circuits provide some protection, but in many cases, the discharge contains enough power to alter device parameters or melt silicon junctions. Generating Static The table below shows activities that generate static electricity and the associated electrostatic voltage level. Typical Electrostatic Voltages Activity Relative Humidity Walking across carpet Walking across vinyl floor 10% 40% 55% 35,000 V 15,000 V 7,500 V 12,000 V 5,000 V 3,000 V Motions of bench worker 6,000 V 800 V 400 V Removing DIPS from plastic tubes 2,000 V 700 V 400 V Removing DIPS from vinyl trays 11,500 V 4,000 V 2,000 V Removing DIPS from styrofoam 14,500 V 5,000 V 3,500 V Removing bubble pack from PCBs 26,000 V 20,000 V 7,000 V Packing PCBs in foam-lined box 21,000 V 11,000 V 5,000 V Note: 700 Volts can degrade a product.

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Presario 1700 Series
Models: XL260, XL261, XL262, XL264, XL265, XL266, XL274, XL275, XL360, XL361,
XL362, XL363, XL364, XL365, XL366, XL367, XL368, XL369, XL370, XL371, XL372, XL373,
XL374, XL375, XL376, XL377, and XL378
Electrostatic Discharge
A sudden discharge of static electricity from a finger or other conductor can destroy
static-sensitive devices or microcircuitry. Often the spark is neither felt nor heard, but
damage occurs. An electronic device exposed to electrostatic discharge (ESD) may work
perfectly throughout a normal cycle and may not seem to be affected at all. However,
although it may function normally for a while, it may be degraded in the internal layers,
reducing its life expectancy.
Networks built into many integrated circuits provide some protection, but in many cases,
the discharge contains enough power to alter device parameters or melt silicon junctions.
Generating Static
The table below shows activities that generate static electricity and the associated
electrostatic voltage level.
Typical Electrostatic Voltages
Activity
Relative Humidity
10%
40%
55%
Walking across carpet
35,000 V
15,000 V
7,500 V
Walking across vinyl floor
12,000 V
5,000 V
3,000 V
Motions of bench worker
6,000 V
800 V
400 V
Removing DIPS from plastic tubes
2,000 V
700 V
400 V
Removing DIPS from vinyl trays
11,500 V
4,000 V
2,000 V
Removing DIPS from styrofoam
14,500 V
5,000 V
3,500 V
Removing bubble pack from PCBs
26,000 V
20,000 V
7,000 V
Packing PCBs in foam-lined box
21,000 V
11,000 V
5,000 V
Note:
700 Volts can degrade a product.