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diode circuit

Discussion in 'Homework Help' started by ramphisaj, Feb 23, 2007.

  1. ramphisaj

    Thread Starter New Member

    Oct 18, 2006
    7
    0
    i need help please see attachment.
     
  2. hgmjr

    Retired Moderator

    Jan 28, 2005
    9,029
    219
    Is it possible that each of of the two circuits in question have a resistor between the junction of the diodes and the positive supply input?

    If not, then the circuits as drawn, while doable, are not very realistic.

    There is bound to be a diode or diodes destroyed in the circuits as drawn.

    hgmjr
     
  3. nomurphy

    AAC Fanatic!

    Aug 8, 2005
    567
    13
    IF you have rendered the schematics for this problem correctly, then I feel sorry for you, because it is a foolish scenario/question.

    Assuming the diodes could somehow handle the current due to the voltage potentials, the answers are:
    1) +5V
    2) +15V

    Because Vout is tied directly to the supply voltage(s) -- especially after the diodes burn up.
     
  4. Johann

    AAC Fanatic!

    Nov 27, 2006
    190
    30
    I think your circuit needs a resistor between +5V and output. Then (and only then), this represents some form of diode logic circuit. In the first circuit (if a resistor is inserted between +5V and out), and assuming a volt drop of 0,7 volts per diode, the two diodes with +5V inputs will not be biassed at all and will have no effect, however, the two diodes with the -5V inputs will be forward biased. The output will then be 0,7V higher than the -5V, i.e. -4,3V.
     
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