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What is a DC to AC Voltage Converter?

Jeremy Laukkonen
Jeremy Laukkonen

In order to convert between direct current (DC) and alternating current (AC), some type of inverter is required. A DC to AC voltage converter essentially switches the direct current source back and forth between positive and negative values using a circuit known as an oscillator. The two main classes of DC to AC voltage converter are differentiated based on whether the output is a modified square or pure sine wave, depending on the complexity of the oscillator circuit. A DC to AC voltage converter can be used to power electronic devices using the batteries found in automobiles, recreational vehicles and boats, solar panels, and other sources.

The difference between direct and alternating current is that electrons in DC circuits move in only one direction, while those in AC circuits periodically reverse their flow. This can be examined by testing the voltage in a circuit. A DC circuit will show a constant, positive voltage if the leads are hooked up correctly, while an AC circuit will cycle between positive and negative voltage. When viewed on an oscilloscope or similar device, the alternating current available from the power grid will appear as a sine wave.

A socket designed for use with AC electricity.
A socket designed for use with AC electricity.

A DC to AC voltage converter functions by switching a direct current source back and forth in order to approximate a sine wave. The oscillator circuits used to accomplish this were once mechanical in nature, though a variety of solid state designs have been created. Simple converters create a type of modified square wave that involves the voltage staying positive for a time, dropping directly to zero, moving in a straight line to a negative voltage, and then back again. Square wave AC power is sufficient for many devices, though in some cases a purer waveform is necessary. Pure sine wave inverters are a more expensive type of DC to AC voltage converter that use additional control circuitry to approximate the sine waves seen in grid power.

Power inverter with DC plug.
Power inverter with DC plug.

An inverter will typically also use transformers and various control circuits to generate the desired level of voltage and current to power a device. Small inverters are available that can plug into the cigarette lighter in a car, which typically provides a limited amount of wattage. The power output of an inverter tends to be limited by the input circuit. Inverters that are used with solar panel installations can provide power to an entire house, and pure sine wave models are often used to tie these systems into the grid.

Discussion Comments

Hawthorne

The article says that solar panels hooked up to inverters can power a whole household. I was wondering if that meant that solar panels are by default direct current power.

I've been wanting to put some solar panels into my home for a long time. It's actually not a house; I live in a little tiny trailer that I pull behind my truck. I'm working on visiting all 50 United States.

Anyway, there's just enough space on top of the trailer for a few solar panels. I think it would be awesome to be able to generate my own power no matter where I go. If it'll take a power inverter, too, though, that might jack up the price too much. Solar panels themselves are far from cheap, and I'm afraid I'll spend all of my available funds on them and then not be able to use them because they require an inverter.

Do solar panels come with their own inverters? If not, how expensive would it be to buy myself an inverter that would work for my purposes -- converting power from two solar panels into AC power for my living space inside the trailer?

seHiro

@malmal - That sounds a bit intimidating, but calm down and take a deep breath. You're not the first American to travel to Iceland and want to keep their electronics in working order, certainly.

As the article notes at one point, many power inverters also act as a voltage controller, releasing the desired amount of voltage that you need for electronics such as your computer. I'll bet if you did some searching and comparisons online, you could find a power inverter that converted Icelandic wall plugin types to the standard American wall plugin type as well as modulating the amount of electricity that comes out into your computer.

If not, get a regular American power inverter that can control the amount of electricity, and use one of the wall plugin converters that simply plug in on both sides. It should make the inverter usable in Icelandic wall sockets, and you're all set! Hope this helps you out. Have a good trip, and my condolences to your husband and his family.

malmal

Has anybody here ever heard of a travel voltage converter? I'm going to Iceland for the next month on an extended visit to see some family members of my husband's thanks to one of his aunts passing away, and I just read that Iceland has different kinds of electric sockets than they have here in the United States!

The different prong arrangements don't sound so bad -- apparently there are adapters you can buy that you can plug your regular American plugins into and then plug the cord on the other end into the wall. What really worries me is that apparently in most other countries the electric voltage coming from a socket is about 100 volts more than it is here in the United States.

Help! Is there a converter that will switch the cord type and also work like a surge protector to keep my computer from getting fried when I plug it into the wall in Iceland? It's going to feel like another planet over there if I don't even have my computer to use.

VivAnne

I grew up in a homestead style household on a road that did not have electricity. We didn't even have power lines! Because of the lack of electricity, any time my parents wanted to run the TV or any other electric appliance (although most things like lights and the stove were run by propane), they would have to use a power inverter.

AC is the alternating current that is supplied to most households, and also the one that electrical appliances use. Now, our primary source of power -- a power bank made out of several 12v car batteries wired together -- was DC. DC is direct current, the kind of power used for batteries and battery charging.

In order to use the car battery, my parents had to buy a 12v DC inverter to attach to the car battery. It had little clamps to hook to the positive and negative connectors on the battery, and the inverter had just two regular AC electric sockets on the front of it. It did the trick great, though -- we could plug the TV to a car battery and watch movies.

Thanks to my upbringing, I know what an inverter is off the top of my head, which seems to surprise most people.

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    • A socket designed for use with AC electricity.
      A socket designed for use with AC electricity.
    • Power inverter with DC plug.
      Power inverter with DC plug.
    • Batteries produce direct current (DC) electricity.
      By: Scanrail
      Batteries produce direct current (DC) electricity.
    • A brush electric motor, which uses DC power.
      By: MCE-128
      A brush electric motor, which uses DC power.
    • A DC to AC voltage converter can be used to power electronic devices using the batteries from solar panels.
      By: Aania
      A DC to AC voltage converter can be used to power electronic devices using the batteries from solar panels.
    • The conversion between DC to AC voltage can be viewed on an oscilloscope.
      By: motorlka
      The conversion between DC to AC voltage can be viewed on an oscilloscope.