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Can transformer create power

  1. Jul 5, 2015 #1
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    theroteically using transformers cant create power then why a light bulb connected with a step up transformer can become brighter
  2. jcsd
  3. Jul 5, 2015 #2
    Useful links you should check if you didn't:

    Voltage: https://en.wikipedia.org/wiki/Voltage
    Ohm's law: https://en.wikipedia.org/wiki/Ohm's_law
    Current: https://en.wikipedia.org/wiki/Electric_current
    Transformer: https://en.wikipedia.org/wiki/Transformer
    Power: V x I, I2R, V2/R

    A step up transformer doesn't generate any extra power, it only interchanges current with voltage: it can elevate the voltage but the maximum current provided by its output lowers wrt to input current and provides he same (or lower, due to efficiency issues) power.
    Because a bulb requires a voltage that the transformer's output provides to generate enough current to light up its filament (or LED or whatever), but if the transformer can't provide enough current , the bulb won't light up.
    Last edited: Jul 5, 2015
  4. Jul 5, 2015 #3


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    Science Advisor
    Homework Helper
    Gold Member

    There are two ways to visualise a power supply and a load (light bulb).

    1) The power supply delivers a certain amount of power to the load.
    2) The load draws (sucks?) a certain amount of power from the supply.

    It's sometimes better to think in terms of 2) rather than 1).
  5. Jul 5, 2015 #4
    then what makes the bulb connected to a step up transformer become brighter
  6. Jul 5, 2015 #5


    Staff: Mentor

    The bulb is brighter due to Increased power output from the source. The transformer does not provide any power itself, but it can make a load draw more power from a source.
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