In automation systems, relays are commonly used for what role?

• A. They act as the brains of the machine
• B. They are used only as safety devices
• C. They store data in memory
• D. They provide power supply

Answer: (A)

Relays are electromechanical switches that let a small control signal switch a larger load, enabling simple control logic and sequencing. In automation, they interpret sensor inputs and drive actuators, coordinating the machine’s actions. This control function is why they’re described as acting like the machine’s brain in basic systems. They aren’t merely safety devices, they don’t store data in memory, and they don’t provide power.