Amplifiers / Transformers

Discussion in 'Homework Help' started by James4553, Aug 30, 2008.

  1. James4553

    Thread Starter Active Member

    Jun 7, 2008
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    Hi Guys,

    Do amplifiers and transformers basically do the same thing?
    I know an amplifier amplifies an input signal (amongst other things) from, say, a 10V Peak to Peak input to a 20V Peak to Peak output; but couldn't a transformer just do the exact same thing with a 10V Peak to Peak input by having a turns ratio of 1:2?
    Or is a transformer only for DC?
     
  2. mik3

    Senior Member

    Feb 4, 2008
    4,846
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    Transformers work only with AC not with DC. Also, transformers dont amplify power, like a power amplifier, but only transform the level of voltage and current but the output power is almost the same as the input power (a bit less due to losses).
     
  3. James4553

    Thread Starter Active Member

    Jun 7, 2008
    35
    0
    Ok, so transformers only work with AC. What about amplifiers? Do they only work with AC also? Can an amplifier decrease the input signal or only increase it?

    Also, I don't understand what you mean when you say that the output power is almost the same in a transformer. If you are transforming the input voltage and current to a higher level, how is it that the power is not increased?
    i.e. P=VI
     
  4. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    Some amplifiers work only with AC and some amplifiers work only with DC and some with both AC and DC, this depends on the design. Yes, you can design a circuit that can reduce the voltage rather than increase it but you dont call in an amplifier because it does not amplify.

    In a transformer as the output voltage increases the output current decreases, thus the power remains the same.
     
  5. James4553

    Thread Starter Active Member

    Jun 7, 2008
    35
    0
    Thanks, that clears it up.
     
  6. beenthere

    Retired Moderator

    Apr 20, 2004
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    It's still an amplifier - the gain is just less than 1.
     
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