An Uninterruptible Power Supply (UPS) is a device that provides immediate backup power when the main electricity source fails. It contains a battery that supplies electricity to connected equipment, preventing data loss, system crashes, and potential hardware damage. Beyond just backup power, a UPS also acts as a power conditioner, protecting devices from common electrical problems like voltage surges, sags, and fluctuations, ensuring a clean and stable power supply. This makes it essential for protecting sensitive electronics and critical equipment.