Online Uninterruptible Power Supply (UPS) charges the battery from the AC's main supply and further supplies power to the load via an inverter. So in times of insufficient power accumulation, there is no interference to the output supply because the battery supports the load via the inverters. The on-line UPS system is suited to sensitive applications. Online UPS takes in all types of frequencies and voltage and converts them into the constant clear flow of AC power.

Online UPS akin to its name provides an online uninterrupted power supply to the connected loads, which are critical to halt even for a fraction of a second, no matter whether it's a power outage or a brownout. All the power-sensitive electronics loads are a must to be connected to the online UPS. Otherwise, the quality of the power or even a slight surge or a spike could wreak havoc on the equipment and in turn, ruin the entire system it is connected. The downtime itself costs heavily besides rectification charges, and above all, there's nothing to surprise in case the damage gets beyond repair. Therefore, Online UPS are a must everywhere, considering the quality of the power we receive, like – 1. Hospitals and Private Clinics 2. Research Centres and Laboratories 3. Process Industries 4. Computers, Data Centres, Server rooms and Search Data Centers 5. Network operation Centres and Telecommunication Networks 6. Commercial areas with expensive equipment 7. Sensitive House-hold equipment

An Online UPS is typically used to safeguard hardware such as data centers, computers, telecommunication equipment, or other electrical equipment where an unexpected power disruption could cause injuries, fatalities, critical business disruption, or data loss. This online UPS is perfect for environments where electrical isolation is essential or for equipment that is very subtle to power fluctuations.

An uninterruptible power supply or uninterruptible power source, UPS is an electrical device that offers emergency power to a load when the input power source, typically the utility mains, fails. An online UPS Device is one where the UPS output is always supplying current to the load. This UPS system is an older and cheaper style that only adjusts the UPS output to the load when the prime fails, causing a momentary spike that can rest computers and create restrictions. However, with the online system, the mains uninterruptedly supply charging current to the batteries, and the UPS output is produced from the batteries; therefore, when the mains fail, there is no switching of the output voltage. Such a system also offers extra protection from short circuits and voltage shedding on the mainline.

Online UPS provides zero interference to the output load even when the supply fails as there is no transfer to battery power compared to offline UPS because they can compensate over and under power supply without the use of the battery. They manage to provide a consistent and reliable power supply to networks running applications.

A solar inverter or PV inverter, is a type of electrical converter which converts the variable direct current output of a photovoltaic solar panel into a utility frequency alternating current that can be fed into a commercial electrical grid or used by a local, off-grid electrical network.