The UPS is essential to protect computers and electronic devices from electrical surges and voltage drops, avoiding breakdowns, data loss, and blockages on modems, routers, and telephone lines. By equipping yourself with a UPS unit, it is, therefore, possible to completely solve the problem. Let’s see how it works, how to choose it, and what are the criteria for choosing the best UPS according to your needs.

The UPS has the function of protecting electrical devices from voltage surges and keeping them on and working for some time, so as to allow us to continue the activities in progress, or simply turn off the devices in total safety.

It happens to everyone to experience a power surge or a real blackout, while we are working on the PC, and to lose precious data before being able to save it. Unfortunately, this possibility can happen in various situations, and more frequently than you think.

A blackout, for example, blocks operations and clears the memory of the last unsaved data, blocking access to routers and ADSL. In addition to the interruption of activities in progress, we have to deal with the damage that sudden voltage variations can cause to the various devices.

To ensure that this eventuality does not happen, the first thing to do is to get an uninterruptible power supply, also called UPS, an acronym for Uninterruptible Power Supply.

The UPS, therefore, becomes absolutely essential for the protection of the PC in the first place and of all electronic devices connected to the electrical outlet, at home or in the office. To decide which best ups for computer to choose for your needs, you need to understand if you need a device for home or office use.

How to choose a UPS: types and characteristics

Starting from the idea that by purchasing an uninterruptible power supply we are entrusting the security of our hardware to an instrument that is unparalleled in its function, we must be sure that the product we are going to choose corresponds perfectly to the characteristics we are looking for.

By using an unsuitable model, in fact, we could obtain the opposite effect, namely that the UPS does not support the connected devices during the power surge, and therefore can damage appliances, memories, and work.

The first important distinction is to know that there are three types of UPS: online, line-interactive, and offline. Let’s see what the differences are and what are the characteristics to be evaluated to be sure to choose the most suitable UPS.

Online (double-conversion)

These professional UPSs are the least common type in the home, basically due to their high cost. In UPSs of this type, the incoming alternating current, coming from the electrical network, is converted into a direct current to recharge the battery.

At the same time, we have a second conversion: the direct voltage coming out of the battery is transformed into an alternating current to power the appliances and devices in operation. When there is a power failure, the trip time (period of time between the power failure and the UPS trip) is practically zero.


This type is the most recommended if you want a good quality/price ratio and is the most common in the home or in medium-small businesses. In this type of domestic UPS, the input current is filtered and regulated thanks to the AVR (Automatic Voltage Regulator, a circuit that has the function of damping peaks and compensating for voltage drops).

When a sudden drop in electrical current occurs, the inverter activates the batteries, which power the connected devices. Uninterruptible power supplies with pure sine wave inverters produce a flow of electricity identical to that of the power grid. The intervention time is between 5 and 10 milliseconds, sufficient for the equipment to remain on anyway.


This is the cheapest type of UPS. The input current goes directly to power the devices, even in the presence of voltage fluctuations, whether they are more or less serious. Meanwhile, the power supply keeps the battery charged, to keep it always ready in case of immediate intervention. The action time is approximately 10 milliseconds.


Before purchasing a UPS, you need to check the wattage required. The power is expressed in both Watts and VA, so we will find indications such as 1500 VA / 900 Watts.

We need this parameter to understand how many and which devices to connect. In fact, if we need to connect several devices, they must not exceed the overall wattage indicated by the product, otherwise, it will not be able to withstand the overload deriving from the instrumentation and will not withstand a voltage surge.

High wattage is therefore recommended for those who have to connect multiple servers or appliances in the office, while a lower wattage could be fine to connect a single PC for home use.


Another fundamental requirement is the maximum autonomy that our UPS guarantees us. We can find models ranging from 5 to 30 minutes. The device, being powered by batteries, will certainly have an autonomy shorter than the duration of a black-out, but at least it allows you to switch off your instrumentation in complete safety.


The UPS is powered by 12V batteries, some models can contain two to give the device greater autonomy. It can take 4 to 8 hours to recharge the batteries.

To ensure the perfect functionality of our UPS, it is good practice to replace the battery at least every 2-3 years, depending on its quality and use. It would also be better not to overload it, not to completely discharge the battery, and, in periods of inactivity, completely disconnect the device.