Date: Mon, 29 Dec 1997 18:57:36 GMT Server: Apache/1.2.4 lock_local/0.1 Last-Modified: Thu, 27 Feb 1997 07:04:05 GMT ETag: "1b497a-233b-331531e5" Content-Length: 9019 Accept-Ranges: bytes Connection: close Content-Type: text/html FAQ - ESD

Applied Computer Technologies, Inc.

Advanced Technology Computer Systems, Peripherals, & Services


FAQ - Electrostatic Discharge



What is electrostatic discharge (ESD)?

Electrostatic discharge (ESD) is a fairly common occurrence. Basically, you may notice electrostatic discharge when you walk across carpet, and then touch a metal object. The shock that you feel is called electrostatic discharge. If the discharge is lower than 3000 volts, then you will not feel the shock; however, the discharge can still damage an electronic component.


What causes ESD?

Static electricity is an electrical charge at rest; it is usually created by friction as stationary ions do not move in a current. Generally, a static charge will accumulate on the surface of a non-grounded conductor, and on non-conductive surfaces, such as plastic or clothing. One surface begins to accumulate negative-charged electrons while the opposing surface will accumulate positive-charged electrons. When the non-grounded conductor comes in contact with a grounded conductor, the charge is released. Turn off the lights in a room, slide your feet across the carpet, and then touch another person, occasionally, you may see the static electricity discharge from your finger. If you can feel the charge then, you discharged at least 3,000 volts of static electricity. If you could hear the discharge, then you discharged more than 6,000 volts. If you could see the discharge, then you discharged more than 8,000 volts. There are several products that generate ESD including polyethylene, vinyl, foam, polyurethane, synthetic textiles, fiberglass, glass, and rubber.


How does ESD affect my computer?

Many customers decide they want to install new components in their system. Whether these components are upgrades or new peripherals, the components and the computer are very sensitive to ESD. Often ESD can damage the computer or component beyond repair, so use caution when you work on your system. It does not take may volts to damage an electronic component. A charge of less than 3000 volts can damage most electronic components.


What type of damage can ESD do?

ESD can cause two different types of damage to a system, upset failures and catastrophic failures. A catastrophic failure indicates that the electrostatic discharge damaged the component beyond repair. The component will not function again. This type of damage is usually the easiest to detect. Most authorized service centers can quickly detect this type of damage to a system or component. Although ESD may have damaged an electronic component, the component may still function; this is referred to as upset or latent failure. Although the component will still function, the integrity of the component has been sacrificed. The component may not perform properly, or the life of the component may diminish. This type of damage is difficult to detect since the component will still function; however, some service centers have the ability to detect this type of damage.


What components can ESD affect?

ESD can affect most electronic components, including hard drives, system boards, expansion cards, floppy drives, processors, cache, and most other components that use electronic circuitry.


How can I prevent ESD from damaging a computer or computer component?

Use caution! Now that you know what ESD is, you can prevent this type of damage by taking care before you alter your computer. You can touch a piece of metal before you touch a computer component to release the built-up static, and prevent the charge from damaging the system.

Consider a static-control product. If you frequently handle electronic components, you may want to consider purchasing some preventative equipment.

Static strap - Most static straps come in the form of a wrist strap that you can wear around your wrist. The other end of the strap should be attached to a grounded piece of metal, such as a rail on the computer. Most computer stores sell these straps.

Rubber mats - Many manufacturers sell rubber floor and table mats that you can use to prevent static discharge. Although these mats can prevent static discharge from damaging the component, if you pick up the component, then it is susceptible to ESD damage.

Static-shielding bags - These bags are ideal to store a component that you do not plan to install, or that you remove from the system. Often, when you purchase a new peripheral, the new component is shipped in a bag that you can save for later use.

Keep your workspace clear. Clear any excess materials in the work area. Most manufacturers market their components in a box encased in cellophane; remove the cellophane from the work space once you unwrap the new component. Since most plastics are exceptionally conductive, keep them clear from the workspace.

Use caution when you handle an electronic component. Hold the component by the edges. Do not touch any of the soldered components on the board. If you need to set the device down, then place it on the static-shielding bag. If you pass the component to another person, the other person must be grounded, or you risk damaging the component. Keep components away from your hair and clothing.



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Changes last made on: February 27th, 1997