Electronics with Transistor (another problem)

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Homework Help Overview

The discussion revolves around a problem involving a transistor circuit, specifically focusing on finding the collector current (Ic), emitter current (Ie), and base current (Ib). Participants are analyzing the implications of certain conditions, such as Ic being zero, and discussing the calculations related to the transistor's operation modes.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the correctness of their calculations for Ic, Ie, and Ib, with some questioning the implications of defining Ic as zero. There are inquiries about the relevance of using scientific notation for current values and concerns about potential confusion with units. Others explore the definitions of saturation and cutoff points in transistor operation.

Discussion Status

Some participants have provided guidance on the calculations and the interpretation of the problem, while others are still seeking clarity on specific aspects of the circuit and the definitions involved. Multiple interpretations of the problem's requirements are being explored, particularly regarding the conditions under which Ic can be considered zero.

Contextual Notes

Participants note that there are words in the problem statement that are difficult to translate, which may affect their understanding. The problem includes specific conditions for finding Vce and Ic at different operational points of the transistor.

  • #31
I found this little electronics store... and they could fix my charger! :smile:
Me and my laptop are back in business again! Yeah! :!)
 
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  • #32
Femme_physics said:
(from your post #5)
I'm just not sure about the last 2 clauses...is it all correct?

Hi FP ! :smile:

In working through your exercise, I agree with your sol'ns for Ib, Ie, Vce, Vre. Good job ! :smile:
However I don't believe you've correctly solved for Vb. Why do you feel Vb (the voltage at the base of the transistor) is only equal to IbRb??
Hint: if 12V is the potential (metaphorically, at the top of the hill) and you come part way down the hill to Vb. What should Vb equal?

I agree with ehild that answers are preferred in engineering, w/o so many zeros. (either scientific notation or using prefixes mA , \muA, mV, \muV). If you really like the zeros (for your peace of mind), you might state your answer e.g. 0.000043A = 0.043mA

There is something in this problem that will help you on the https://www.physicsforums.com/showthread.php?t=525613" (the one with the voltage divider R1 and R2, biasing network). In fact the labeling of the variables (eg. Vb, Rb) in the current problem is a hint at how useful it is to define them this way.

What I am referring to is your equation in the current problem that looks something like:
(a) : Vb - IbRb - Vbe - IeRe = 0
I recommend using this equation, in your earlier exercise. I promise, it will simplify your calculations immensely. (You may want to review how I defined Vb and Rb in https://www.physicsforums.com/showthread.php?t=525613&page=3,#35")

I miss your hand drawn-diagrams (photographed). :frown: Some of your new 'scans' are not bold or enlarged enough to read clearly. Your hand-drawn photographed images added a wonderful creative touch to your posts :smile:
 
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