Which of the following small-signal model is/are the correct repr
A. <img alt="" src="//storage.googleapis.com/tb-img/production/20/09/F1_Shubham_Madhu_24.08.20_D4.png" style="width: 282px; height: 148px;" />
B. <img alt="" src="//storage.googleapis.com/tb-img/production/20/09/F1_Shubham_Madhu_24.08.20_D5.png" />
C. <img alt="" src="//storage.googleapis.com/tb-img/production/20/09/F1_Shubham_Madhu_24.08.20_D6.png" />
D. None of the above
Please scroll down to see the correct answer and solution guide.
Right Answer is:
SOLUTION
Analysis:
Small-signal model for h-parameters:
In the small-signal model for π-parameters:
\({h_{ie}} = {r_π }\)
\({h_{fe}} = \beta \)
\(\frac{1}{{{h_{oe}}}} = {r_0}\)
The small-signal h-parameter model can be replaced with the π model as shown:
From the above model, we can write:
\({V_π } = {I_b}{r_π }\)
\({I_b} = \frac{{{V_π }}}{{rπ }}\)
\(\beta {I_b} = \beta \cdot \frac{{{V_π }}}{{{r_π }}} = {g_m}{V_π }\)
The π model therefore becomes:
∴ Options 1, 2, and 3 are correct.
