Alternating current facts for kids
An alternating current (AC) is a type of electric current where the direction of the electricity keeps reversing. Think of it like a wave moving back and forth, instead of flowing in just one direction. This is different from direct current (DC), which always flows in the same way.
Most of the time, when we talk about AC, we mean the electricity that powers our homes and businesses. This electricity comes from a power plant. In many places, the direction of the current switches 60 times every second. In other parts of the world, it switches 50 times a second. This happens so fast that things like light bulbs don't even flicker or go out.
The most common shape for an AC power wave is a sine wave. This shape is best for sending energy over long distances. But for some special uses, other shapes like triangular or square waves are used.
AC is also used for things like audio and radio signals that travel through wires. For these, the main goal is to get information that's hidden inside the AC signal.
Contents
The Story of Alternating Current
The idea of alternating current has a fascinating history. Many smart people helped make it what it is today.
Who Invented AC Power?
Nikola Tesla was a very important inventor who worked a lot with electricity. He experimented with how electricity vibrates and studied different ways to light things up. He created an induction motor, which is a type of electric motor, and new kinds of generators and transformers. His work was key to developing the AC power system we use now.
The War of the Currents
In the late 1800s, there was a big competition between AC and direct current (DC). Thomas Edison supported DC, which was good for short distances. But AC systems could send electricity much farther without losing a lot of power. This was a huge advantage!
Many other inventors also helped make AC better. These included George Westinghouse, Lucien Gaulard, John Dixon Gibbs, Wilhelm Siemens, and Oliver Shallenger. They all helped AC become the main way to deliver electricity.
Early AC Power Plants
One of the first important AC power plants was built in 1893. It was called the Mill Creek hydroelectric plant and was near Redlands, California. It was designed by Almirian Decker. This plant used a special type of AC called 10,000 volt three-phase electric power. This three-phase system eventually became the standard way for power plants all over the world to produce electricity.
How Alternating Current Works
AC power is used because it's cheaper and easier to send electricity over long distances. It also makes it simpler to create many electronic devices.
Why AC is Better for Power Transmission
One big reason AC is used is that you can easily change its voltage. This is done using devices called transformers. When you send electricity over long distances, it's best to use very high voltages and smaller currents. This helps reduce the amount of energy lost as heat in the wires. If you tried to send DC power over long distances, you would lose a lot more energy.
How Transformers Help
transformers are everywhere! You can see them on top of utility poles and sometimes even underground. They help change the voltage of AC power up or down. This makes it possible to send electricity efficiently from power plants to your home.
The Flow of AC
Alternating current works by constantly switching the direction of the electric flow. It goes back and forth many times each second. This continuous switching is what makes AC so effective for powering our modern world.
Related pages
See also
In Spanish: Corriente alterna para niños
Images for kids
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A picture showing how electricity is sent over long distances. From left to right: G=generator, U=step up transformer, V=voltage at beginning of transmission line, Pt=power entering transmission line, I=current in wires, R=total resistance in wires, Pw=power lost in transmission line, Pe=power reaching the end of the transmission line, D=step down transformer, C=consumers.
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These are transmission lines that carry high-voltage AC power. They help send electricity over long distances from power plants to people's homes. These lines are in eastern Utah.
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The Hungarian "ZBD" Team (Károly Zipernowsky, Ottó Bláthy, Miksa Déri), who invented the first very efficient transformer.
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This is an early version of the ZBD transformer, on display in Nagycenk, Hungary.
