What is the function of UPS and where is it used?

Uninterruptible UPS power supply is used to supply power to electrical equipment in case of power failure, just like the generator, but the power supply of UPS power supply is battery-powered, so there will be no switching time for UPS to supply power to equipment, or it will be very short, so you won't feel it. Computers, experimental instruments, hospital medical equipment, related systems of banks, airport signal systems, train signal systems and many other systems need UPS power supply, and all places that are afraid of power failure need UPS power supply, not just computers.