2 Transistor circuit and voltage notations

Thread Starter

Liqauttro

Joined May 23, 2015
17
Hey There
I have a few questions about the attached circuit picture(it is a solved example from Borow's book) :
1)Why isn't Vbb mentioned?Is that because of its equality to Vcc?
2)Why is the alternative circuit true ? Why did the Vcc notation remain in its place and also Why was a Dc source called Vcc added ?

Thanks in advance for all the helpers
I will be glad to see your altenraive circuits diagrams since This one isn't really clear for me
 

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Thread Starter

Liqauttro

Joined May 23, 2015
17
Ok ,thank you for your diagram , it made things clearer although that
I still don't understand where Vbb notation dissapeared(Is it required ? if not ,so why ?)
Could you help me with that?
 

Thread Starter

Liqauttro

Joined May 23, 2015
17
Oh sorry ,I probably didn't make myself clear enough
Ok, Vbb is the voltage seen on the pictures attached
Now ,Bobrow ,the author of the book uses in its book when sketching
a diagram of every circuit which includes NPN BJT t, and he simply omitted this notation on this specific diargram
I wanted to ask you why he did that
 

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Thread Starter

Liqauttro

Joined May 23, 2015
17
Also ,pay attention that on the second diagram(on the right one) Vbb isn't mentioned explicity ,yet ,it is written in the explaination above it that Vbb=Vcc=10V
 

Thread Starter

Liqauttro

Joined May 23, 2015
17
Ok, so actually on the first diagram we started with ,you actually say Vbb=Vcc,am I right ? and since
that Vbb doesn't appear ?
 

ericgibbs

Joined Jan 29, 2010
18,766
In the first circuit the Base bias upper resistor is connected to Vcc, which is typical.

The author has then reduced the circuit to show Vcc supplying the Base as a separate voltage source, which should be named Vbb driving the base resistors, note that Vbe is the voltage between the Base and Emitter.
 

Thread Starter

Liqauttro

Joined May 23, 2015
17
Ok ,understood ,I actually got really confused with his notations
Now you made it clearer
Thank you very much for your help ,sir!
 
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