Answer:
An online UPS.
Step-by-step explanation:
An online UPS is a type of uninterruptible power supply uses AC power to continuously charge its battery, while also providing power to devices through the battery. It combines the inverter and rectifier to provide power to the alternating current (AC) load while supplying alternating current (AC) power during an outage to the load through the inverter.
Basically, an uninterruptible power supply unit is used to provide constant power supply to an electrical device, especially during a power outage.