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  • Atmospheric CO2 Level Tops 400 ppm
    During the week of May 13th, the CO2 level at the Mauna Loa Observatory in Hawaii topped 400 ppm rep...Read more

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    Atmospheric CO2 Level Tops 400 ppm

    During the week of May 13th, the CO2 level at the Mauna Loa Observatory in Hawaii topped 400 ppm repeatedly. Daily levels of CO2 can vary due to weather, and there are seasonal trends as well. The level of atmospheric greenhouse gases continues to increase, now over 120 ppm since the Industrial Revolution began. For more on the Keeling Curve, see http://keelingcurve.ucsd.edu/. Find out more about greenhouse gases and warming.
  • Massive Tornado Outbreak on Tornado Alley
    The week of May 19 brings dozens of tornadoes to Tornado Alley in the states of Oklahoma, Kansas, Io...Read more

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    Massive Tornado Outbreak on Tornado Alley

    The week of May 19 brings dozens of tornadoes to Tornado Alley in the states of Oklahoma, Kansas, Iowa, Illinois and Missouri. On May 20th, a massive tornado struck Moore, Oklahoma, devastating communities - destroying over 100 homes and hitting two elementary schools and a hospital - with many casualties and deaths. Our thoughts are with our friends and colleagues suffering from these storms. For more on the May 20th storms, see the NOAA Storm Prediction Center Storm Report.
  • Kansas Legislator Proposes Bill to Outlaw Sustainability Education
    A bill has been introduced in the Kansas legislature this week that would prohibit the promotion of ...Read more

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    Kansas Legislator Proposes Bill to Outlaw Sustainability Education

    A bill has been introduced in the Kansas legislature this week that would prohibit the promotion of sustainability. Here is a link to the one-page bill: http://www.kslegislature.org/li/b2013_14/measures/documents/hb2366_00_0000.pdf. See report on Bloomberg News.
Transformers are often used in electrical circuits to change the voltage of electricity flowing through a circuit.
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Image courtesy of Wikipedia (modified by Windows to the Universe staff).

Voltage Transformers in Electric Circuits

Transformers (sometimes called "voltage transformers") are devices used in electrical circuits to change the voltage of electricity flowing in the circuit. Transformers can be used either to increase the voltage (called "stepping up") or decrease the voltage ("step down").

Transformers have two coils of wire in them. The coils of wire are wound around an iron core. The wires aren't connected to each other. One wire coil has more loops than the other. When AC (alternating current) electricity flows in one wire, it makes a magnetic field around that wire. The magnetic field causes electricity to flow in the other wire. Since the wire coils have different numbers of loops, the voltage in the second wire is different from the voltage in the first wire. That's how transformers change the voltage in a circuit.

Transformers are very efficient. Under normal conditions they transmit about 99% of the power that enters them (about 1% of the power is lost as heat).

When electricity travels from a power plant to your house, it passes through transformers along the way. High voltage is good to use for sending electricity long distances through wires because less energy is lost that way. However, we need low voltage electricity in our houses because it is safer. Transformers change the voltage of electricity as it moves from a power plant to your home.

Last modified February 25, 2009 by Randy Russell.

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