FAQ03309 of Basic Switches FAQ

The term of Contact Switch is used compared to the Semiconductor Switch. The Contact Switch performs the switch function by mechanically switching contact points. Since the semiconductor has no contact points, the Semiconductor Switch is also called "Non-contact Switch" compared to "Contact Switch". The products adopting the Contact Switch include the Micro Switch, Limit Switch and Electromagnetic Relay. On the other hand, the products using the Non-contact Switch include the Solid State Relay (SSR).

As for the features of the Contact Switch, its advantages over the Non-contact Switch are: enhanced input and output separation, low output ON resistance and high output OFF resistance, high over-voltage and over-current protection, relatively low price; while its disadvantages are: high electric noise generation when switching the contact points, limited switching life of the contact points, chattering occurred by mechanical vibration and shock.