Ideal Voltage Amp

Discussion in 'Homework Help' started by James4553, Mar 5, 2009.

  1. James4553

    Thread Starter Active Member

    Jun 7, 2008
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    Could someone please explain to me why an ideal voltage amp would (ideally) have the input impedance as infinite??
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Infinite input impedance means no power used to drive it's input. No distortion effects on the input. Basically, think of every possible loading effect on a signal, and why the ideal op amp will not exhibit any of them.
     
  3. GirishC

    Active Member

    Jan 23, 2009
    58
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    For voltage amplifier, if you have input impedance very high (infinite) compared with input series resistance/ impedance, the input voltage comes across high values and that's the requirement for voltage amplifier. In case of current amplifier its other way round and its true even using opamp.
     
  4. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    Because an infinite input impedance would be desired if possible. This is because no current would flow into (or out of) the input of the amplifier, no voltage would be dropped across the internal impedance of the signal source and the whole voltage provided by the signal source would appear at the amplifier's input and thus a higher output voltage would be got.

    Still confused! :p
     
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