HP dx2040 Service Reference Guide: HP Compaq dx2040 Business PC - Page 31

Generating Static, Preventing Electrostatic Damage to Equipment, Electrostatic Discharge Information

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Networks built into many integrated circuits provide some protection, but in many cases, the discharge contains enough power to alter device parameters or melt silicon junctions. Generating Static The following table shows that: ● Different activities generate different amounts of static electricity. ● Static electricity increases as humidity decreases. Event 55% Walking across carpet 7,500 V Walking across vinyl floor 3,000 V Motions of bench worker 400 V Removing DIPs* from plastic tube 400 V Removing DIPs* from vinyl tray 2,000 V Removing DIPs* from Styrofoam 3,500 V Removing bubble pack from PCB 7,000 V Packing PCBs in foam-lined box 5,000 V *These are then multi-packaged inside plastic tubes, trays, or Styrofoam. Relative Humidity 40% 15,000 V 5,000 V 800 V 700 V 4,000 V 5,000 V 20,000 V 11,000 V 10% 35,000 V 12,000 V 6,000 V 2,000 V 11,500 V 14,500 V 26,500 V 21,000 V NOTE: 700 volts 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 damage to electric components and accessories. ● 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. Electrostatic Discharge Information 23

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Networks built into many integrated circuits provide some protection, but in many cases, the discharge
contains enough power to alter device parameters or melt silicon junctions.
Generating Static
The following table shows that:
●
Different activities generate different amounts of static electricity.
●
Static electricity increases as humidity decreases.
Relative Humidity
Event
55%
40%
10%
Walking across carpet
Walking across vinyl floor
Motions of bench worker
Removing DIPs* from plastic tube
7,500 V
3,000 V
400 V
400 V
15,000 V
5,000 V
800 V
700 V
35,000 V
12,000 V
6,000 V
2,000 V
Removing DIPs* from vinyl tray
Removing DIPs* from Styrofoam
Removing bubble pack from PCB
Packing PCBs in foam-lined box
2,000 V
3,500 V
7,000 V
5,000 V
4,000 V
5,000 V
20,000 V
11,000 V
11,500 V
14,500 V
26,500 V
21,000 V
*These are then multi-packaged inside plastic tubes, trays, or Styrofoam.
NOTE:
700 volts 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 damage to
electric components and accessories.
●
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.
Electrostatic Discharge Information
23