Table 4-1
Static electricity occurrence based on activity and humidity (continued)
Relative humidity
Event
55%
40%
10%
Multiple electric components can be packaged together in plastic tubes, trays, or polystyrene foam.
NOTE:
As little as 700 V of static electricity can degrade a product.
Preventing electrostatic damage to equipment
Many electronic components are sensitive to ESD. Circuitry design and structure
determine the degree of sensitivity.
The following packaging and grounding precautions are necessary to prevent static
electricity damage to electronic components:
●
To avoid hand contact, transport products in static-safe containers such as tubes,
bags, or boxes.
●
Protect all electrostatic parts and assemblies with conductive or approved containers
or packaging.
●
Keep electrostatic-sensitive parts in their containers until they arrive at static-free
stations.
●
Place items on a grounded surface before removing them from their container.
●
Always be properly grounded when touching a sensitive component or assembly.
●
Avoid contact with pins, leads, or circuitry.
●
Place reusable electrostatic-sensitive parts from assemblies in protective packaging
or conductive foam.
Personal grounding methods and equipment
Using certain equipment can prevent static electricity damage to electronic components.
●
Wrist straps are flexible straps with a maximum of 1 MΩ ±10% resistance in the
ground cords. To provide proper ground, a strap must be worn snug against bare
skin. The ground cord must be connected and fit snugly into the banana plug
connector on the grounding mat or workstation.
32
Chapter 4 Removal and replacement procedures preliminary requirements
