UPS, or uninterruptible power supply, is an uninterruptible power supply that contains energy storage devices. It is mainly used to provide uninterrupted power supply to some equipment that requires high power supply stability.

When the mains input is normal, the UPS will stabilize the mains and supply it to the load. At this time, the UPS is an AC-type voltage stabilizer, and it also charges the battery in the machine; when the mains is interrupted (accidental power failure) Immediately, the UPS will continue to supply 220V AC power to the load by switching and converting the DC power from the battery to the load, so that the load can maintain normal operation and protect the software and hardware of the load from damage. UPS equipment usually provides protection against over-voltage or under-voltage.