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Why are these two circuits equivalent?

somewhatreal

Aug 18, 2022
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I'm sorry. It's not really homework and I'm sure that it's a really simple and dumb question but I need some help with this guided exercise.
Why are these two circuits equivalent even without the connection between R2 and RC? Thank you to the kind soul that will answer.

ese1.pngese2.png
 

Minder

Apr 24, 2015
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Separate supplies for Input and output, both with a common point makes them equivalent, also allows for different power supply sources at different levels for both input and output.
 

Ylli

Jun 19, 2018
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On the first circuit, what is the voltage at the top of R2? What is the voltage at the top of Rc?
On the second circuit, what is the voltage at the top of R2? What is the voltage at the top of Rc?
Is there any difference?
 

Ylli

Jun 19, 2018
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What ensures that the base voltage of the BJT stays the same?
What would make the base voltage different?

Note that in the second circuit, both voltage sources are labeled "Vcc". Since they are labeled the same, we generally assume that the
Voltage of Vcc = Voltage of Vcc.
 

Ratch

Mar 10, 2013
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I'm sorry. It's not really homework and I'm sure that it's a really simple and dumb question but I need some help with this guided exercise.
Why are these two circuits equivalent even without the connection between R2 and RC? Thank you to the kind soul that will answer.

View attachment 55902View attachment 55903
The transistor won't knw the difference because the voltagdes on the base circuit and collector are the same in both cases. However, the voltage souecew on the left side will carry less current than the right side, but transistor won't know the difference.
 
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