Eliminating Static Electricity Hazards Ensures Safety
1. Proper Grounding
Modern computers generally have a ground wire. This ground wire, along with the AC live wire and ground wire, is connected to two small capacitors. Poor grounding can cause a slight electric shock (only 110V, a very small current) to sensitive individuals just by touching the metal of the computer case. Chips can withstand voltages far less than 110V, so if computer equipment (such as the host, printer, monitor, etc.) is not fully grounded, the printer port and graphics card will be damaged. Many inferior power strips appear to be three-wire systems, but their internal ground wire is not connected at all. Users should pay special attention when purchasing them.
2. Chip and Circuit Board Packaging
Manufacturers generally pay close attention to ESD, and computer components are usually packaged in anti-static bags before leaving the factory. Packaging materials with good insulation properties are prone to ESD, such as bubble wrap and foam plastic bags. These materials are unsuitable for packaging computer components.
3. Static Electricity Handling for Operators and Maintenance Personnel
Computer operators must always remember the dangers of ESD and avoid touching internal circuit boards as much as possible. If contact with internal circuitry is unavoidable, use a grounding ring on your fingers.
4. Static Electricity Handling in the Workplace
Workplaces with the resources should use anti-static flooring (Note: Walking on carpets can easily generate high-voltage static electricity, and low indoor humidity can also easily generate static electricity). The ideal humidity level is 40%-60%.
5. Improving ESD Resistance by Mounting Chips on Circuit Boards
Single chips have low ESD resistance. Mounting chips on circuit boards provides higher ESD resistance. This is the principle behind short-circuiting the pins of easily damaged CMOS chips before transporting them.
6. Grounding is also necessary for measuring instruments and soldering irons during operation.
7. Improving the Quality of Components
To protect computer ports from ESD damage, the most effective method is to improve the internal quality of the components. Currently, some high-quality circuit boards incorporate overvoltage and overcurrent protection devices on their I/O ports. Internationally, a series of testing standards have been specifically developed for the design and manufacture of new devices. For example, many industrial serial port devices from MAXIM have ±15kV ESD protection, which must pass tests such as human body model, IEC 1000-4-2 contact discharge, IEC 1000-4-2 air gap discharge, and IEC 1000-4-4 electrical fast transient/burst discharge. These tests must be performed multiple times under normal operation, shutdown, and power-off conditions.