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The three components of a control system can be described using this simple flowchart:

The control program will contain all the instructions needed for the computer to decide when to turn the actuators on and off. They would normally be planned using a flowchart first then entered into the computer using a programming language.

Examples of Real-Life Control Systems

All these control systems are examples of open-loop systems – they stop after they have made the actuator do something.

Situation Decision to Make
Microwave If the ‘start’ button is pressed, heat the food inside for 30 seconds.
Door bell If the button is pressed, buzz a bell for five seconds.
Lamp If the switched is pressed in, turn the lamp on. If the switch is pressed out, turn the lamp off.
Television set Turn the television on or off when the standby button is pressed on the remote control.
Screen turtle Move the turtle in the direction of the arrow key that is pressed.

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