What Is the Current Amplification Ratio in a Bipolar Junction Transistor?

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Homework Help Overview

The discussion revolves around determining the current amplification ratio (β) in a bipolar junction transistor (BJT) using given base and collector currents. The context is within the common emitter configuration of BJTs.

Discussion Character

  • Exploratory, Conceptual clarification

Approaches and Questions Raised

  • Participants discuss the calculation of β using the relationship between base current (IB) and collector current (IC). Some express uncertainty about the simplicity of the problem, questioning if they are missing a deeper concept or if it is indeed straightforward.

Discussion Status

There is a general agreement on the calculated value of β being 100. However, participants are exploring the nature of the problem, with some expressing that it feels too simplistic compared to typical assignments. The discussion includes reflections on the expectations of deriving equations versus straightforward calculations.

Contextual Notes

Participants note that the professor usually assigns more complex problems requiring derivation of equations, which raises questions about the nature of this particular assignment. There is also mention of a hypothetical scenario where the emitter current is given instead, which could complicate the problem.

TehBigBoss
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Homework Statement


If IB and IC (IB = Base current and IC = Collector current) of bipolar junction transistor are 1mA and 100 mA respectively, determine its current amplification ratio in common emitter configuration.

Homework Equations


IC=β*IB
Where β = current gain = \alpha/(\alpha-1) (is this the same as current amplification ratio)?

Where \alpha = IC/IE (IE = Emitter current)

The Attempt at a Solution


I understand that whatever signal is input in through the base is amplified out through the collector.

I found this page very helpful http://230nsc1.phy-astr.gsu.edu/hbase/solids/trans2.html#c6

β = IC/IB = 100mA/10mA = 100

Was this problem really that easy?! Or am I missing something big here? Professor usually assigns pretty involved homework problems.

Thank you.
 
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100 is right. Too easy?
 
Well he usually give us problems where we have to derive our own equations to use. This one seemed too much like a plug and chug question considering that equation was all over the lecture and book. Thank you though!
 
TehBigBoss said:
Well he usually give us problems where we have to derive our own equations to use. This one seemed too much like a plug and chug question considering that equation was all over the lecture and book. Thank you though!
The solution would have been slightly more challenging had you been told that it was the emitter current that was 100mA, determine β.
 

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