* Find \[V_B, V_E, V_C\].

* If \[R_B\] changes to \[270k\Omega\], find \[V_B, V_E, V_C\].

* For what value of \[\beta\] will voltages V(B),V(E),V(C) get back to previous values.

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Here's what I got.

\[I_B=0.074977mA\]

\[I_C=2.24932mA\]

\[I_E=2.3243mA\]

\[V_B=2.0244V\]

\[V_C=-2.9268\]

\[V_E=6.65757\]

If R(B) changes to 270k:

\[I_B=0.02347mA\]

\[I_C=0.70398mA\]

\[I_E=0.72745mA\]

\[V_B=6.3358V\]

\[V_C=-7.09924\]

\[V_E=7.03588\]

Here comes the 'problem', finding Beta...

I calculated \[I_B\] using the previous (first) V(B) value.

\[I_B=0.0074977mA\]

So If V(C) gets back to the previous value, I(C) should be the same.

And \[\beta = \frac{I_B}{I_C}=300\].

But I realized I can find Beta with another method, using K-laws.

\[9-2.7kI_E-0.7-270kI_B=0\]

using:

\[I_B=\frac{I_E}{\beta +1}\]

and the value of I(C) found first, I get:

\[\beta =309\]

Can anyone tell me if any of the solutions is right or wrong and why.

Thanks in advance.