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Need help with finding gain for a 2 stage amplifier

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sid1616

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Hey guys!

I am unable to find vout and vin for this problem. I was only given 2 values in the problem of the collector current and B=100. And the values for resistances.I figured out a couple of values I'm not sure if they are right.

Can someone please help me as to how to solve this problem further to find vin and vout!

I've attached a screenshot of my problem ?

1 - pQuoOmy.jpg
 
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The beta of a transistor affects its current gain, not its voltage gain.
The voltage gain of a transistor is roughly RC/RE so without a load the voltage gain of the first transistor is 5k/2k= 2.5 times at its collector and is almost 1.0 at its emitter.

The base-emitter diode of the second transistor seriously overloads the emitter of the first transistor and the second transistor does not have a collector resistor or power supply for it so it has no output.
 

If voltage across RE is 0.6V or higher, then current flows into the bias leg of Q2. If this happens then it causes Q1 to conduct a little more, pulling output V downward a bit.

Your schematic appears to label Q2 collector current 2mA. I don't believe this has any influence on Q1 VO.

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Edited to add: I notice you calculated a small bias current going to Q2. This allows you to assume that voltage on RE is 0.6V (or maybe .4 or .5V). Then calculate current through RE. This should allow you to calculate backward, then eventually find VO.
 

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