Overview
This lecture explains static electricity, electrostatic discharge (ESD), the risks ESD poses to computer components, and best practices for preventing ESD during handling and storage.
Static Electricity and ESD
- Static electricity is the build-up of electrical charge on a surface, often felt as a spark after walking on carpet.
- Electrostatic discharge (ESD) occurs when built-up static electricity moves to equalize electrical potential between two objects.
- Silicon components in computers are highly sensitive to ESD; as little as 100 volts can cause damage.
- A common human static discharge (e.g., touching a doorknob) can reach about 3,500 volts.
ESD Prevention Techniques
- Maintaining humidity levels above 60% can reduce static, but is usually impractical for comfort and HVAC systems.
- Self-grounding by touching a metal chassis equalizes electrical potential between you and the computer equipment.
- Always unplug the power connection before working on computer systems to avoid electrical shock, though it does not affect ESD protection.
- Never attach yourself directly to a building's electrical ground as it can be hazardous.
Anti-Static Equipment and Handling
- Anti-static straps worn on the wrist and connected to a device's metal part prevent ESD.
- Anti-static pads can be used on desks, connected to the device, to further reduce risk.
- Anti-static mats are helpful when standing and moving around during repairs.
- Use anti-static bags for storing or transporting components to safely minimize ESD risk.
- Always handle components by their edges and avoid direct contact with circuitry.
Storage Best Practices
- Store computer components in environments regulated between 50–80°F (10–27°C).
- Components should be kept in low humidity; use silica gel packs in anti-static bags to absorb moisture.
- Store components in original boxes when available, or wrap anti-static bags in bubble wrap for protection.
Key Terms & Definitions
- Static Electricity — an accumulation of electrical charge on a surface.
- Electrostatic Discharge (ESD) — the sudden flow of electricity between two objects with different electrical potentials.
- Self Grounding — touching a metal part of a device to equalize electrical charge before handling components.
- Anti-static Strap — a wrist strap that grounds you to prevent ESD.
- Anti-static Pad/Mat — surfaces designed to minimize static electricity during repairs.
- Anti-static Bag — a storage bag that protects components from static discharge.
- Silica Gel Pack — a drying agent placed in storage bags to reduce humidity.
Action Items / Next Steps
- Practice self-grounding and use anti-static equipment when handling computer components.
- Store components in anti-static bags and regulated environments with silica gel packs.
- Always unplug devices before beginning repairs.