A defibrillator is a medical device used to restore a normal heartbeat in someone experiencing a life-threatening heart rhythm problem, such as cardiac arrest. It delivers an electric shock to the heart, which can help reset its rhythm. There are different types of defibrillators, including automated external defibrillators (AEDs) that are designed for use by the general public and can guide users through the process. Using a defibrillator is often crucial in emergencies, as every second counts when someone is in cardiac arrest. Many public places, like airports and schools, have AEDs available to help save lives. Learning how to use a defibrillator can empower bystanders to act quickly and effectively in critical situations.