Hello

"Semiconductor Devices and Basic Applications " page 435, the booktalks about:





Figure 6.63 (b) is the small signal equivalent circuit. Notice that the dependant current source directed from the collector to the emitter.

In other pdf file I found in:

http://www1.i2r.a-star.edu.sg/~ongmichael/Chapter67.pdf


On page 137 the following small signal equivalent circuit:



Here the dependant current source directed from the Base to the Collector.

My question: Is these MODELS are equivalent? If yes, how?

Thank you

 

In the first document note that \(V_\pi\) is equivalent to Vbe. In the second document V is Veb. Hence the source direction reversal is consistent with the opposite polarity notations for the controlling parameter.

However, the source should presumably still be located between emitter & collector rather than base & collector.

 

In the first document note that \(V_\pi\) is equivalent to Vbe. In the second document V is Veb. Hence the source direction reversal is consistent with the opposite polarity notations for the controlling parameter.

However, the source should presumably still be located between emitter & collector rather than base & collector.

thank you
please take a look on:

 

Thank you all
I have discovered the reason for this discrepancy
The reason is that one of them using the hybrid pi model, where the other using the T model
please look at the attached file

 

Good point.
One would also have to make the distinction that \(\text{r_\pi \ and \ r_i }\) as shown in the two equivalent circuits aren't the same.

 

Good point.
One would also have to make the distinction that \(\text{r_\pi \ and \ r_i }\) as shown in the two equivalent circuits aren't the same.

Yes, I agree entirely with you
Thank you t_n_k