What Is a Power Inverter

A power inverter is a device that converts DC power (also known as direct current), to standard AC power (alternating current). Inverters are used to operate electrical equipment from the power produced by a car or boat battery or renewable energy sources, like solar panels or wind turbines. DC power is what batteries store, while AC power is what most electrical appliances need to run so an inverter is necessary to convert the power into a usable form. For example, when a cell phone is plugged into a car cigarette lighter to recharge, it supplies DC power; this must be converted to the required AC power by a power inverter to charge the phone.

How Inverters Work

DC power is steady and continuous, with an electrical charge that flows in only one direction. When the output of DC power is represented on a graph, the result would be a straight line. AC power, on the other hand, flows back and forth in alternating directions so that, when represented on a graph, it appears as a sine wave, with smooth and regular peaks and valleys. A power inverter uses electronic circuits to cause the DC power flow to change directions, making it alternate like AC power. These oscillations are rough and tend to create a square waveform rather than a rounded one, so filters are required to smooth out the wave, allowing it to be used by more electronic devices.

Most electronic devices require AC power to work correctly because they are designed to be plugged into a standard wall outlet, which supplies AC power. These devices need a specific amount of low, regulated voltage in order to operate. AC power is easier to step up or down, or change from one voltage to another, than DC and easier to regulate. In many cases, when a power inverter is in use, DC power is being converted to AC power, which is then stepped down and turned back into DC power inside the device.

Types of Inverters

Most modern power inverters produce either modified square (or modified sine) waves, or pure sine (or true sine) waves. Modified square wave inverters don't provide the smooth peaks and valleys that AC power from a home's electrical outlet does, but it can deliver power that is consistent and efficient enough to run most devices. This type of inverter is relatively inexpensive, and probably the most popular type.

Pure sine wave inverters are the most expensive, but they also deliver the smoothest and most even wave output. Any device will run on a pure sine wave, but some sensitive equipment, like certain medical equipment and variable speed or rechargeable tools, requires this type of inverter to operate correctly. Radios, for example, work better with pure sine wave inverters because the modified square wave inverter's less-smooth waves disrupt the radio's reception, causing static and other noise.

Inverter Uses

Basic power inverters are often small, rectangular devices that plug directly into the cigarette lighter or DC outlet on the dashboard of a car or other vehicle. This size inverter is usually sufficient to run a laptop, a small television, a portable DVD player, or similar equipment. These devices don’t draw a lot of power and can be used continuously while the vehicle is running; they may even be used for a half-hour to an hour while the engine is off, such as while camping or during a power outage at home.

Other power inverters come with jumper-like cables so they can be connected directly to a battery. This type is required to run more powerful equipment, such as power tools at a remote work site or a larger TV. Inverters can also be hard-wired into a battery to make them easier to use with larger pieces of equipment.

Larger inverters are used to convert solar or wind energy into AC power that can be used in a home. Called a grid-tie inverter, this device links into the utility grid to allow power to be delivered along the same wires that supply energy from a electric utility. It even allows any excess power produced to be fed back into the grid, where it can be sold to the utility company.

Inverter Capacity

Different models of power inverters vary in how many watts of power they can supply. The capacity of an inverter should equal the total number of watts required by each device, plus at least a 50% addition to account for peaks or spikes in the power draw. For example, if a DVD player draws 100 watts and a small TV another 100 watts, a minimum 300-watt inverter is recommended. Getting an inverter with more capacity than what is immediately needed is a good idea for many people, as it means that different or new devices can be added without the need for a new power inverter.

Safety

When using a power inverter continuously inside a vehicle that is not turned on, the engine should be started at least once an hour for 10 to 15 minutes to keep the battery from running down. A vehicle should never be started in a closed garage, as the carbon monoxide in the exhaust is fatal. 

Power inverters should only be used with batteries that are in good condition and fully charged. A weak battery will be drained easily if demand is too high. If used in a car, this could leave a driver stranded, so the battery's condition should be checked before using an inverter in a stationary vehicle. If the inverter is being used while the vehicle is running, as in the case of a road trip, there should be no problem with the extra draw as long as the battery is in good condition.

Working with large batteries can be dangerous, and when not done properly, can result in serious injury. Improper use of a power inverter can even lead to electrocution. For safety reasons, someone attempting to hook an inverter directly to a battery should be sure to read and follow any and all safety precautions listed in the inverter's instruction booklet.

It is important for people to always use a power inverter that is rated high enough for the device that needs to be run. If a heavy-duty power saw is plugged into a cigarette lighter, for example, the lightweight inverter might overheat and cause a fire in the dashboard. Adapters that allow more outlets than the unit is designed to accommodate should be avoided, and proper ventilation around the inverter is required to prevent overheating.

What is a Hydrogen Bomb

A hydrogen bomb is, by far, the most destructive weapon that mankind has ever invented. It is the most powerful type of nuclear bomb, as much as 25,000 times the yield of the nuclear bombs dropped on Hiroshima and Nagasaki, Japan. Unlike conventional atom bombs (also known as A-bombs), which release energy by fissioning (breaking apart) heavy atomic nuclei like uranium and plutonium, a hydrogen bomb releases energy by fusing together light nuclei like tritium or deuterium, converting even more matter into energy. When Truman authorized the dropping of the A-bomb on Hiroshima and Nagasaki, he said that the weapons used the same power that the Sun did, but that wasn't actually true -- the Sun uses nuclear fusion, not nuclear fission. Thus, a hydrogen bomb really does release the power that fuels the Sun.

The largest nuclear bombs, and the backbone of the nuclear arsenal of the United States and Russia, are hydrogen bombs. These bombs work using a two-stage design whereby a fission bomb "primary" is detonated using the conventional implosion method, which then compresses a fusion fuel "secondary" and ignites a uranium "spark plug" which fissions and subjects the fusion fuel to the heat necessary to begin a chain reaction -- about 20 million degrees F. The light nuclei fuse together into heavier elements, releasing tremendous energy from the strong nuclear force that binds their constituent particles together.

As a result of using fusion rather than fission, the bomb yield is much higher. In fission bombs, approximately 0.1% of the mass of the fuel is converted directly into energy, while in fusion bombs, this ratio is slightly improved, on the order of 0.3%. The first time the principle of a hydrogen bomb was tested was on 9 May 1951 by the United States military, during the George shot of Operation Greenhouse at the Pacific Proving Grounds. Most of the yield of this test came from fission fuel, but it tested the idea that a fission bomb could be used as a stepping stone to something even more destructive. A similar test, Item, took place on 25 May 1951.

The first true hydrogen bomb test, Ivy Mike, was on 1 November 1952, detonated at Enewetak Atoll in the Pacific, as part of Operation Ivy. The bomb exploded with a force equivalent to 10.4 megatons of TNT (over 450 times more powerful than the atomic bomb dropped on Nagasaki during WWII). Using liquid deuterium as fuel, this hydrogen bomb required 18 tonnes of refrigeration equipment to keep the deuterium in liquid form. A later test, Castle Bravo, used solid lithium deuteride instead, decreasing the weight of the device and making it a practical weapon. The Castle Bravo shot is the most powerful nuclear weapon ever tested by the United States, with a yield of 15 megatons.

Today, all of humanity is still put at risk by a nuclear winter initiated by hydrogen bombs.

How Can I Play the Music on my Computer Through my Stereo

Music files have revolutionized the way people listen to and archive music. Soft MP3 players, or software designed to play music files, have made it easy and convenient to build ad-hoc playlists for any occasion or mood. Although programmable compact disk (CD) players allowed some flexibility to create playlists, the ease of clicking to add tunes to a software interface makes other forms of programming feel downright archaic and restrictive by comparison. It’s no wonder then that people want the option of using soft MP3 players to listen to music files through the main stereo system or entertainment center. Luckily, it’s an easy thing to do, and it can be done wired or wirelessly.

The most common and least expensive way to route music from your computer to your stereo system is to run an RCA audio cable from the sound card on the computer to the stereo receiver. All sound cards are made with at least one Line Out jack, used to power computer speakers. The jack is normally a 3.5mm mini phone plug. An inexpensive adapter that features a 3.5mm stereo jack at one end, and two female RCA jacks at the other will work well here. This will connect to a standard RCA stereo cable. The opposite end of the cable will plug into the stereo or surround sound receiver. Here you’ll need an available Audio Line In RCA port, which may be marked Aux for auxiliary. 

After the connection is made, set the volume down before powering up the receiver. Change the receiver mode to auxiliary (rather than tuner, CD, DVD, TV, etc.), and slowly turn the volume up. You may need to boost the volume control of soft MP3 player as well. 

Advanced sound cards might also have other Line Out options, such as Digital Out. The instructions are the same, substituting a digital cable for the RCA cable. The receiver will also need a Digital Audio-In port.

Though wired methods are inexpensive, they have the disadvantage of requiring a physical cable to run from the computer to the stereo system. If the computer is a desktop located in a different room from the stereo or entertainment center, this can be impractical. A laptop provides a good mobile medium for music libraries, as it can be set rather close to the stereo system to simplify things and keep wires out of walkways.

When hard wiring your music connection isn’t practical, another method is to go wireless. In this case a small transmitter is connected to the Line Out port of the sound card, and a matching receiver is connected to the Audio Line In port of the receiver. Music from the computer is silently broadcast via radio waves from the transmitter to the receiver. The receiver interprets the radio signals and translates them back into an audible signal to play through the speakers of the entertainment center. 

Wireless stereo transmitters vary in design and pricing and a few models are expressly designed for iTunes music. Others include composite video ports to send not just audio, but video signals between the computer and entertainment center. Cables might be included or sold separately. For more information check your local electronics stores or your favorite online retailers.