The Best Use of a Relay Switch

A relay switch is an electrically-operated switch. A type of relay that can handle the high power needed to directly drive an electric motor is called a contractor. Relays with calibrated operating characteristics and sometimes multiple operating coils are used to protect electrical circuits from overload or faults, which could potentially damage equipment or cause injury to those who manage and maintain the system. In today’s electric power systems, these types of functions are handled by protection relays.

A variety of circuits can be connected to electrical relay switches. They can be used as amplifiers for electrical energy. Many electrical fail safe systems utilize electrical relays which turn on or off in response to a current overload, irregular current or other “oddities” that may develop. These electrical relays trip and will shut the system down so the issue can be addressed in a safe manner.

Relay switches are often used in small applications, such as in a car alarm or home kitchen appliances, or for applications that require a massive amount of power. In locations where a large amount of power needs to be switched, relays are often cascaded. In this situation, a smaller relay switches the power needed to drive a much larger relay, and that second relay switches the power to drive the load.

Solid State Relay Switch

A solid state relay switch is a control relay with an isolated input and output. They utilize electronic components without the use of moving parts, like those in electromechanical relays. It is worth noting, however, that solid state relay switches offer a much longer lifespan than electromechanical relays.

The way a solid state relay works is similar to electromechanical relays that both use a circuit as well as a separate circuit for switching the load. When the electrical current is applied to the solid state relay input, the relay switch is then energized by a light emitting diode (LED). The diode directs a beam into a light-sensitive semiconductor that alerts the control circuit to turn on the output of the solid state switch at the next zero voltage crossover.