Electrostatic Discharge; Generating Static - Compaq Prosignia 190 Maintenance And Service Manual

INDEX PAGE
REMOVAL & REPLACEMENT
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 not be affected at all
and will work perfectly throughout a normal cycle. Although, it may function normally for a
while, then degrade 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.
The table shows how different activities generate static electricity and at different electrostatic
voltage levels.
Typical Electrostatic Voltages
Event
Walking across carpet
Walking across vinyl
floor
Motions of bench
worker
Removing DIPS from
plastic tubes
Removing DIPS from
vinyl trays
Removing DIPS from
Styrofoam
Removing bubble pack
from PCBs
Packing PCBs in
foam-lined box
NOTE: 700 volts can degrade a product.
MAINTENANCE & SERVICE GUIDE
P
ROSIGNIA
PRODUCT DESCRIPTION
ILLUSTRATED PARTS CATALOG

Electrostatic Discharge

Generating Static

Relative Humidity
10%
35,000 V
12,000 V 5,000 V
6,000 V
2,000 V
11,500 V 4,000 V
14,500 V 5,000 V
26,000 V
21,000 V
N 190
OTEBOOK
LEGAL NOTICE
TROUBLESHOOTING
40% 55%
15,000 7,500 V
V
3,000 V
800 V 400 V
700 V 400 V
2,000 V
3,500 V
20,000 7,000 V
V
11,000 5,000 V
V
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