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What is the difference in applying -ve voltage at emitter and +ve coll

  1. Feb 15, 2013 #1
    What is the difference in applying -ve voltage at emitter and +ve voltage at collector in attached circuit image? Really what I think is both circuits in thae image are identical. But then why -VEE?

    -Devanand T
     

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  3. Feb 16, 2013 #2

    vk6kro

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    Re: What is the difference in applying -ve voltage at emitter and +ve

    The power supply voltages also affect the necessary input voltages.

    For example in the second diagram, the transistor with -1.3 volts on its base will be turned off if the negative supply line is grounded but it is conducting if this line is at -5.2 volts.

    This is because the base is more positive than the negative supply line in the second case, but less positive in the first case.
     
  4. Feb 17, 2013 #3

    NascentOxygen

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    Re: What is the difference in applying -ve voltage at emitter and +ve

    Over what range of input voltages will the arrangement in (a) function as an amplifier?

    What about (b)?
     
  5. Feb 17, 2013 #4
    Re: What is the difference in applying -ve voltage at emitter and +ve

    the circuit in (a) is basic ECL unit, range of inputs is 2 logic states at input -1.7 V and -0.8 V.

    I was asking that what difference (a) has with (b) in voltage supply applied in terms of polarity.
     
    Last edited: Feb 17, 2013
  6. Feb 17, 2013 #5

    NascentOxygen

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    Re: What is the difference in applying -ve voltage at emitter and +ve

    (b) will function in the same manner, but not with the input/output voltages that cause (a) to work.
     
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