Electrostatic Discharge; Generating Static - Compaq 12XL125 - Presario - K6-2 533 MHz Maintenance & Service Manual

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 not seem to be
affected at all and works perfectly throughout a normal cycle. 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.
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.
2 R S
EMOVAL EQUENCE
Presario 1200 Series
Models: XL101-XL113, XL115, XL118-XL127
Typical Electrostatic Voltages
Relative Humidity
10% 40%
35,000 V 15,000 V
12,000 V 5,000 V
6,000 V 800 V
2,000 V 700 V
11,500 V 4,000 V
14,500 V 5,000 V
26,000 V 20,000 V
21,000 V 11,000 V
P N M
RESARIO OTEBOOK AINTENANCE AND
55%
7,500 V
3,000 V
400 V
400 V
2,000 V
3,500 V
7,000 V
5,000 V
S G 1200XL S
ERVICE UIDE ERIES