full bridge rectifier ckt

Discussion in 'General Electronics Chat' started by jose_007, Oct 27, 2012.

  1. jose_007

    Thread Starter New Member

    May 3, 2011
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    please help me with the output waveform of this circuit...I am confused due to presence of fifth diode..
     
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  2. Audioguru

    New Member

    Dec 20, 2007
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    The fifth diode is a Light Emitting diode (LED) drawn upside down and with the light beam missing.
     
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  3. jose_007

    Thread Starter New Member

    May 3, 2011
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    I may be wrong,but I think it is simple diode...

    Also I am sure about orientatation of diode.
     
  4. Audioguru

    New Member

    Dec 20, 2007
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    The diode in the original circuit has reverse bias so it is doing nothing. Then the resistor in series with the diode also has no current so it also does nothing.
     
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  5. autotuner

    New Member

    Oct 2, 2012
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    Unless its a zener for simple regulation and just has been drawn wrong.
     
  6. jose_007

    Thread Starter New Member

    May 3, 2011
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    @audioguru and autotuner
    that's what my first reaction was ,but when I ran it in multisim the result was a rectified wave....

    Thats what is confusing me...
     
    Last edited: Oct 28, 2012
  7. jose_007

    Thread Starter New Member

    May 3, 2011
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    and the simulation in simulink is giving me very low voltage across resistor..

    So I don't know which simulation should I trust...
     
  8. autotuner

    New Member

    Oct 2, 2012
    4
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    Well, if you were looking across both the diode and resistor, then there will be a rectified waveform, because the diode / resistor is basically doing nothing.
    The resistor will show a small voltage across it with any diode reverse bias leakage.
     
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  9. jose_007

    Thread Starter New Member

    May 3, 2011
    24
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    yes,you are right....I checked the waveforms again..and it was my mistake while making oscilloscope connections....
    Thanks everyone for the help
     
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