Chargers convert alternating current from your power outlet into direct current so that the laptop can be recharged. You can use this charger excellently as a replacement or as a backup if your original charger is defective. It is also practical to have a charger as a spare in case the original power supply fails or if you want to use the device outside the home. This way, you always have an extra charger at work, school, or at friends and family.