Evaluation The quality of a USB connector, the terminal is an important factor.
　　Selection of the impact of the terminal:
　　1. conductivity - resistivity minimum material
　　2. ductility - Help terminals forming
　　3. The yield strength - in the elastic range can have a large displacement
　　4. Stress relaxation - terminal for extended use in high temperature or by force, to resist the load capacity can be maintained
　　5. Hardness - reducing terminal metal wear
　　Conductivity copper terminals were good, but poor mechanical strength and heat resistance. When the copper alloy elements, due to differences in the size of the atomic electron transfer process caused by blocked or attenuated produce.
　　Copper is too high strength but its electrical conductivity material deviation.
　　Also known as phosphor bronze phosphor bronze, good flexibility, firmware and strong.
　　Beryllium copper has a high strength, high flexibility, high toughness properties, but the conductive rate deviation.
　　Terminal plating role:
　　1. beautiful
　　2. Protection: extend product life, the product surface coating corrosion resistant material
　　3. Special surface properties
　　A. improve product conductivity
　　B. improve product weldability
　　C. to improve light reflectivity
　　D. reduce contact resistance
　　4. mechanical or engineering nature
　　A. to enhance the strength of
　　B. improve product lubricity
　　C. increase the hardness and wear resistance
　　D. improve product heat resistance, weather resistance, radiation resistance
　　E. prevent carburizing, nitriding