What is UPS and what is it intended for?

The UPS (Uninterruptible Power Supply) is designed to protect against interference from the power supply. Some UPSs have built-in batteries that, in the event of a power failure, overcome the failure by uninterrupted power supply, but failures are not detected. Some UPS have no batteries, so the external battery needs to be purchased. The operating time of the UPS depends on the autonomy (tp, the size of the built-in batteries) and the current load.