An uninterrupted power supply (UPS) provides backup power when there is an outage by using batteries to power critical equipment until utility power returns or a generator starts. UPS systems convert utility power to regulated power and provide battery backup when power fluctuations or outages occur to ensure continuous power for computers and other electronics. UPS units range in size from individual desktop models that protect computers and small networks to large systems that can power entire data centers or industrial facilities during an outage.