- #1
It is about common emitter configurations
- Thread starter saranga
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Discussion Overview
The discussion revolves around the identification and understanding of common emitter configurations in electronic circuits. Participants explore the characteristics of such configurations, including the roles of input and output connections, and how they relate to other configurations like common collector and common base.
Discussion Character
- Technical explanation
- Debate/contested
Main Points Raised
- Some participants question whether the provided diagram accurately represents a common emitter configuration, suggesting it may resemble a common collector configuration instead.
- One participant emphasizes that the input signal must be applied to the base, as the emitter is grounded and does not change voltage, which is a characteristic of common emitter configurations.
- Another participant agrees with the previous point, noting that the collector is typically where the output is taken, reinforcing the definition of common emitter based on the emitter being the common reference point.
- Several participants express uncertainty due to the lack of clear input and output indications in the diagram, leading to speculation about the configuration's classification.
- There is a repeated assertion that the emitter being grounded and serving as a reference for both input and output supports the common emitter classification, though this is presented with some assumptions.
Areas of Agreement / Disagreement
Participants generally agree on the definition of a common emitter configuration, but there is ongoing uncertainty regarding the specific diagram in question, with multiple interpretations being presented.
Contextual Notes
Participants note the absence of explicit input and output connections in the diagram, which complicates the classification of the configuration. There are assumptions made about the roles of various components, such as bias resistors and load resistors, which may not be universally accepted.
- #2
Tom.G
Science Advisor
Gold Member
- 5,661
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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.
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.
- #3
Electron Spin
- 52
- 28
Tom.G said:
Your right Tom, I would guess Rb is a bias Resistor, The Emitter is tied to ground and the Collector to Vcc..Now let's 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...
Sorry for the redundancies in advance...
Tom.G said:
^^^^^^^^^
This definition, right here.
- #4
saranga
- 13
- 0
thanks it should be my faultTom.G said:
- #5
saranga
- 13
- 0
thank you,no your discription is effective.Electron Spin said:Your right Tom, I would guess Rb is a bias Resistor, The Emitter is tied to ground and the Collector to Vcc..Now let's 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...
Sorry for the redundancies in advance...
^^^^^^^^^
This definition, right here.
- #6
lychette
- 413
- 73
Electron Spin said:Your right Tom, I would guess Rb is a bias Resistor, The Emitter is tied to ground and the Collector to Vcc..Now let's 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...
Sorry for the redundancies in advance...
^^^^^^^^^
This definition, right here.
Completely agree...common emitter