A generator creates electrical power, while an inverter changes one type of electrical current to another. There are two different types of electrical current, alternating (AC) and direct (DC). Inverters are used when devices that use AC power need to be used in a car or other place where only DC power is available. The two machines have distinctly different functions, although there are inverter generators which do both for greater energy efficiency.
AC vs. DC Current
Alternating current and direct current differ in that electrons flow back and forth in AC, but only in one direction in DC. Because AC can tolerate higher voltages, it loses less energy when it travels longer distances. As a result, AC is typically used to supply power to most houses and buildings. Most home appliances, therefore run on AC; otherwise, they'd need to convert the AC power that is supplied to the home or building to DC to power the device. Personal computers typically run on DC and contain a rectifier to perform this conversion. In this case, the rectifier is more commonly referred to as a power supply.
How Inverters Work
An inverter takes the existing power that comes in the form of direct current and converts it to alternating current. It does this by sending the current through switches that send it in different directions. Filters may then be applied to smooth out the wave and give it a fixed frequency. Different types of inverters use a variety of filtering methods, depending on how smooth the output needs to be. To convert AC power into DC, a device called a rectifier is used.
One of the most common everyday uses of inverters is to provide power to run different electronics in automobiles. Cars usually produce DC, which is not compatible with most devices meant to use standard household outlets. Most modern cars have an accessory port that a portable inverter can be plugged into, allowing a small TV, cell phone, or other electronic device to use the power. Some small inverters are designed to be plugged into the cigarette lighter of a car.
Larger inverters are used on construction sites to provide electricity for power tools and other devices. Solar and wind energy generators use inverters to convert the power they produce into that which can be used in a home.
An important distinction between an inverter and a generator is that an inverter can only work if there is already a source of electrical energy; it cannot create its own. Unless part of a combination machine, inverters simply convert DC to AC, while a traditional generator cannot change current from one form to another.
How Generators Work
A generator is a machine that converts mechanical energy into electricity. In most cases, electric generators are responsible for providing the energy a home receives. Large-scale electrical generators may be powered by coal, natural gas or nuclear energy. A portable generator commonly uses gasoline or diesel fuel, which is burned to create electricity for use on a construction site or in a building during a power outage.
Generators can be designed to produce either AC or DC electricity, although most used in power stations and for smaller applications generate AC. This is all that traditional generators do, however — they make electricity. If the voltage that electricity needs to be changed, for example, a transformer must be used.
Inverter generators are like traditional generators because they produce AC power, which is then converted to DC power before being converted back to AC. This produces a smoother, steadier flow of power. The conversion also allows the generator to be more fuel efficient, as well as operate more quietly than standard models.
Some people also confuse an inverter with a power converter, even using the terms interchangeably. A converter is used to change voltage from one level to another. Different voltage levels are used in different countries, and travelers to other parts of the world may need a converter to use appliances like hair dryers and electric shavers.