Understanding the Contact Material and Current Carrying Capacity of Micro Switches
Oct 26, 2024
Leave a message
Understanding the Contact Material and Current Carrying Capacity of Micro Switches
The contact materials of micro switches are different, and the current capacity they can carry will also be different. The following are common contact materials and their typical current carrying capacity.
Silver-nickel alloy (AgNi):
Suitable for medium current, generally around 5A-10A. It has good oxidation resistance and is suitable for medium current control applications, but it will burn in high current situations.
Silver cadmium oxide (AgCdO):
Suitable for higher currents, up to 10A-20A, or even higher. It has excellent conductivity and anti-burning properties, suitable for high current and frequent switching occasions, but because it contains cadmium, it is less environmentally friendly and is gradually replaced by silver tin oxide.
Silver tin oxide (AgSnO2):
Suitable for higher currents, usually between 10A-30A. It has excellent conductivity, good arc erosion resistance, and is more environmentally friendly than silver cadmium oxide, suitable for high current applications and occasions with high environmental requirements.
Silver copper alloy (AgCu):
Suitable for low to medium current, generally 5A-15A. It has good conductivity, but its ablation resistance is not as good as silver nickel and silver tin oxide, and it is suitable for low load and infrequent switching occasions.
Gold contact (Au):
Suitable for low current occasions, generally 50mA-1A. It has excellent conductivity and corrosion resistance, and is suitable for precision circuits with small current and low voltage, such as signal control or communication equipment.
When choosing the contact material, it is necessary to consider the current size used, the humidity and temperature of the working environment, the switching frequency and the cost. For example, silver tin oxide is a good choice in the case of high current and frequent switching; while in precision small signal applications, gold contacts are more suitable.