Enterprise Internet of Things Handbook

Actuators

While sensors sense the environment around them, an actuator is responsible for controlling a system by actuating (open/close or on/off). For example, a switch that can be used to turn a light on or off can be controlled via an actuator.

An actuator generally takes a signal which indicates the nature of an operation. For example, if we need to turn a switch on or off, we use a relay.

A relay is an electromagnetic switch that takes in the AC mains power supply at one end and a digital signal at other. The general state of the relay is open and that means there is no power supply flowing through from the mains to our load. Once there is a digital high or a digital low signal (depending on the type of relay), the relay moves to a closed ...