(^318) PC Hardware: A Beginner’s Guide
ESD
Nearly all cases now produced are designed to provide some level of ESD protection, as
long as the case is intact and properly closed and fastened. Many case covers are chemi-
cally treated on their undersides or have copper fittings or strips designed to channel any
electrostatic charge on the case away from the components inside the case.
The real danger from ESD is created when the case is opened and components inside
the case are exposed. A static discharge can travel along the wires that interconnect the
various components on the motherboard. The wires on the motherboard generally lead
to one or more components. When a discharge on a circuit encounters a metallic part with
an opposing charge, the internal wires could explode or weld together, and that’s not a
good thing.
Here are some ESD facts: A majority of a PC’s electronic components use only from 3V to 5V of electricity.
An ESD of 30V can destroy a computer circuit.
You can only feel an ESD that has more than 2,500V.
You can only see an ESD that carries more than 20,000V.Unfortunately, ESD damage is not that obvious. With the really big pops, such as
when an entire chip or circuit is destroyed, it is obvious that you must replace the piece.
However, when a component has been damaged but is not the point of failure, it may
take days, weeks, or even months for the component to fail completely. In the meantime,
it drives you crazy with intermittent failures that cannot be diagnosed.Figure 14-3. An antistatic wrist strap and antistatic mat