The purpose of an alarm clock is to wake you up at a specific time. It is a device that produces a loud noise or other signal at a designated time to wake you from sleep or alert you to a specific event. You can set the alarm clock to go off at a particular time in the morning, for example, to help you wake up and start your day on time. Alarm clocks are also used to remind you of appointments or other important events that you need to be aware of.