![]() |
![]() |
Maintenance &
Service Guide
Presario 1800 Series
Models: 1825 and 1800T
| Home
Page | Notice | Preface | Product
Description | Troubleshooting
Illustrated Parts Catalog | Removal & Replacement Procedures | Specifications
Pin Assignments | Battery
Pack Operations
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 will work 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.
The table shows how different activities generate static electricity at different electrostatic voltage levels.
Typical Electrostatic Voltages |
|||
Relative Humidity | |||
Event | 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. |