# Analog electronics (BJT circuit analysis)

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1. Dec 9, 2016

### adamaero

1. The problem statement, all variables and given/known data

For beta = 100 and assuming ro is very large, what is the DC voltage at the collector?

2. Relevant equations
IB = IE(β+1)

IC = β*IB

3. The attempt at a solution
Since IE = 0.5mA, IB = 0.0505 A
Then, IC = 5.05 A (which doesn't feel right)
VC is the same potential across the 30kΩ load?
I tried doing KCL with those currents (to find the current thought the load resistor).
Should I not be analyzing the direct circuit--should I make an equivalent T-model?

2. Dec 9, 2016

### Charles Link

Your equation should read $I_E=I_B (\beta+1)$. Try again. I think you also need to assume $V_{BE}=.7 \, volts$ (approximately). One hint for you: The capacitors basically block any steady state current trying to go through them so the capacitor is an open circuit for the DC part of the analysis.

Last edited: Dec 9, 2016
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