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It is about common emitter configurations

  1. Oct 11, 2016 #1
    this diagram is said to be an example for common emitter configuration,but to me ,it is just seem like common collector configuration..would someone explain this? ​

    Attached Files:

  2. jcsd
  3. Oct 11, 2016 #2


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    But you didn't show where the input and output are.

    An input signal (if you want gain), changes the applied voltage between Base and Emitter.
    The emitter voltage won't change in this circuit because it's grounded. Therefore the input must be the Base.
    The only way left to get an output is the Collector and typically the signal is the collector voltage referenced to Ground.
    Since the Emitter is used as the reference for both input and output, It is called a common-Emitter configuration.

    If you have a circuit with the Base grounded, the signal input is to the Emitter, and output is from the Collector, you have a common-Base configuration.
  4. Oct 11, 2016 #3
    Your right Tom, I would guess Rb is a bias Resistor, The Emitter is tied to ground and the Collector to Vcc..Now lets assume the input is tied to the Base and the output is picked off the Rc by convention..If we do, then I would guess it is a CE...

    To the OP.. The element that has no input or output and typically tied to grd is the "common", hence, Common Emitter, Base, or Collector..

    Again, since the emitter is grounded and the collector has a Rc or load resistor and guessing the base is being fed a bias voltage from the collector, the only element with no in/output would assumably be the emitter..Once again, with a little supposition, this could be a common emitter configuration since the emitter is common to the input and output, and is grounded.

    Once again, like Tom said..without the in/output being showed we both are kinda' guessing here saranga...:oldsmile:

    Sorry for the redundancies in advance...


    This definition, right here.
  5. Oct 13, 2016 #4
    thanks it should be my fault
  6. Oct 13, 2016 #5
    thank you,no your discription is effective.
  7. Oct 13, 2016 #6
    Completely agree....common emitter
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