Electrostatic discharge (ESD), or static electricity, is the sudden discharge of a high voltage from when two bodies with different electric charges come in contact with each other.
Synthetic materials like those clothes, carpets and furniture are made of are bad offenders, particularly in very dry weather conditions. They are very good insulators and when a charge is built up on them, it will not flow away due to leakage, it must be discharged by coming into contact with another body. These materials generate high voltage Static Electricity charges when rubbed together. All of us have had a mild electric shock from a door handle, a metal cabinet or a similar object, after we have walked some distance over a carpet or vinyl floor, or moved around on a plastic chair. The motion of our body clad in clothing made of synthetic cloth causes us to be charged to a high potential relative to surrounding objects. These mild electric shocks cause us some discomfort when they occur but this is insignificant when we look at the damage they do to modern electronic components.
As a computer technician, you must be aware of the loss it can cause to computers, printers, network equipment, and their components. ESD can cause immediate and noticeable failure of a component that contains semiconductor devices such as processors and memory chips. It can also cause gradual degradation in performance that eventually results in complete failure. Computer parts such as motherboards, network adapters, video cards, and hard drives are very sensitive to ESD. Technicians must take necessary precautions to prevent ESD related incidents when handling this type of equipment.
Some basic ESD precautions include wearing ESD wrist straps, using ESD floor mats, and storing computer parts in ESD bags. Before working on electronic components person must discharge themselves by touching a metal object before touching the component. Controlling humidity levels can also reduce the effects of ESD. Electrostatic charge is maximum when the humidity level is between 10 and 25 percent. It can be reduced by maintaining the relative humidity between 60 and 80 percent.
Some of the essential ESD precautions include the following:
- Wearing ESD wrist straps when working on computer components.
- Placing components on antistatic ESD table mats. Do not remove the components from the packaging until they are ready to be installed.
- Discharging static electricity in your body by touching a grounded metal surface before handling computer components.
- Holding printed circuit boards such as network adapters and memory cards from edges. Avoid touching the semiconductor chips and connection pins on these cards.
- Using conductive flooring in places where repairs are done.
- Using ESD-safe protective packaging for storing and transporting components.
- Controlling humidity levels. Increasing humidity levels to 70 percent or above helps reduce static charge build-up. Cool and dry temperatures build up static electricity.
- Keeping insulating materials (such as plastic bags) prone to electrostatic charging away from static sensitive devices.