How Do You Calculate Vce in a Simple Transistor Circuit?

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Discussion Overview

The discussion centers around calculating the collector to emitter voltage (Vce) in a simple transistor circuit. Participants are analyzing the relationships between various voltages in the circuit and attempting to clarify their understanding of the equations involved.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant expresses confusion about analyzing a transistor circuit and specifically calculating Vce, referencing their own solution and their professor's solution.
  • Another participant suggests that Vce can be calculated as Vc + Ve, providing a numerical example but remains uncertain about the derivation of their professor's equation.
  • A participant points out that since the emitter is grounded, Ve is the same as Vce, indicating a potential simplification in the analysis.
  • Further clarification is offered that Vc should be considered the same as Vce, correcting a previous typo.
  • Another participant challenges the initial calculation of Vc, asserting that it should be 6 volts based on the circuit's parameters, and provides a method to derive Vce by walking through the circuit from the source to the emitter.
  • This participant also states that VBE, which is 0.7 volts, does not play a role in the calculation of Vce, and disputes the initial claim regarding Vc being 3.3 volts.

Areas of Agreement / Disagreement

Participants express differing views on the correct values for Vc and Vce, with some asserting specific calculations while others question those values. The discussion remains unresolved regarding the correct approach and values for these voltages.

Contextual Notes

There are unresolved assumptions regarding the circuit configuration and the values of components, which may affect the calculations. The discussion also reflects a dependency on the definitions of Vc, Vce, and Ve.

verd
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Hi,

I'm having a bit of trouble understanding how exactly to analyze a transistor in a simple circuit... Specifically when finding the collector to emitter voltage, Vce.

I've got to be looking at this incorrectly. Below is the question and the solution. My professor worked out the part that I circled as "their" solution, and I circled what I did.

Could someone explain what I'm doing wrong?

The only equation I needed for this was:
Ic=Beta*Ib

http://synthdriven.com/images/deletable/EEN305%20-%2001.jpg
 
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nevermind. I'm a complete retard. I Vce should be:

Vce=Vc+Ve=3.3+0.7=4v.

But I am still a bit confused about how my professor derived his equation. That looks like a good equation for Vc, not Vce... Atleast to me.

Could someone explain this to me?
 
Since the emitter is grounded, Ve is the same as Vce.
 
Oops, typo, I meant Vc same as Vce.
 
your professor calculated Vc for 6 Volts right? now walk backwards through the source to the emitter to get VCE.

So +6V - 10V = -4V, so VCE has to be 4V.

Or walk the other way from emitter to collector through the source. +10V-6V=4 Volts.

VBE which is 0.7 volts plays no role here. in your calculation you say Vc is 3.3V which is NOT correct! it is 6V because RC(2kohm) *Ic(3mA) = 6V!

hope that helps.
 

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