Relays can be considered as switches which close and open circuits electronically or electromechanically. Basically these devices simply control one electrical circuit by closing and opening contacts in another circuit. Keeping in mind control and safety aspect, almost all electrical power systems use them. Whether it's an electric plant to power an entire city or small system for personal use, without them safe control of power would be close to impossible. Many relay manufacturers, relay suppliers, exporters are offering optimum quality relays to customers.