subject: Dc Vs. Ups Power Systems [print this page] The acronyms DC and UPS are probably familiar to you. You might think the first acronym is the name of one of the most famous comic companies in the world or maybe a shoe company. And the last one is easy. You probably think it's the name of a shipping company whose deliverers wear brown shorts. But you might not realize that these two acronyms together refer to something entirely different, something we use far more often that either of the other possible definitions.
DC
In this case, DC stands for direct current. Direct current refers to the unidirectional flow of electric charge. DC is one of the forms of electricity that we use every single day. The other form of electricity we use is called alternating current or AC. Alternating current is the type of power that flows from power lines to your home. When you plug in your appliances or power tools, you are using alternating current power. The reason we use alternating current is because it is the easiest for power plants to generate. Direct current, on the other hand, is the type of energy that comes from batteries or solar panels.
Because AC is used for power transmission, everything that plugs into a main power outlet is using AC power. However, things like electronics are powered by DC power, therefore most electronics have some kind of AC/DC power adapter, like your cell phone charger.
UPS
In this case, UPS stands for uninterruptible power supply. You are probably familiar with it as a battery back-up. During the loss of utility power, a UPS system supplies power in order to maintain function. Many computers have UPS so that in case of a power outage, you can safely save your information to your hard drive and shut down your computer by hand. There are two main types of UPS.
A standby power system, or SPS, monitors the power line from the utility power and switches to batter power when a problem is detected. Because of this, there can be miniscule moments during the time it takes to detect the outage and switch to UPS when the device is not receiving power. This can be from 2-10 milliseconds. An online UPS, on the other hand, is constantly providing power through its own inverter, even under normal power conditions.
From behind the scenes, these sources of power are what keep everything in our world running, from your washer and dryer, cell phone, coffee maker, refrigerator, computer to power plants, schools, and other essential functions.