Many electronic Line Replaceable Units (LRU's) on aircraft contain printed circuit boards containing components that are susceptible to damage from electrostatic discharges. Such components are referred to as electrostatic discharge sensitive (ESDS) devices. Decals installed on ESDS LRU's, indicate that special handling is required
Static Electricity & Electrostatic Discharge
The most common conception of static electricity and its accompanying discharge, is the miniature lighting shock you receive when you touch a metal door handle having walked across a nylon carpet. If the door handle is touched with a key first, the discharge will be seen but not felt.
The discharge occurs because different materials receive different levels of charge as materials are rubbed together or pulled apart. The different charge levels create potential differences between the different materials, and when materials of different electrical potential are brought into close proximity with each other, a discharge occurs as the potentials equalise.
The different levels of charge with respect to cotton (the reference material) are shown on the following page, in what is known as the Triboelectric Series.
The further up or down, the greater the charge and hence the greater the discharge when the two materials are brought together.
Triboelectric Series
Material
Increasingly Positive | |
Increasingly Negative | |
When checking for ESD. I use a Resistivity Meter. It's one of the best tools that I have ever used. I especially like that I can record all of my measurements.
ReplyDeleteI use a resistivity meter to check for ESD to. Thanks for the great information.
ReplyDeleteI agree...resistivity meters are one of the best inventions I have ever used. Thanks for the great post!
ReplyDelete