ExamBro
ExamBro
TS EAMCET · Physics · Semiconductors

The voltage-current characteristic of a diode during forward bias is given by \(I=7.8 \times 10^{-5} e^{6.5 V_D}\), where \(I\) is the current in \(\mathrm{mA}\) and \(V_D\) is the diode voltage in \(\mathrm{V}\). Find the dynamic resistance of the diode in \(\Omega\), when the current is \(4 \mathrm{~mA}\)

  1. A 18.6
  2. B 21.7
  3. C 28.2
  4. D 36.2
Verified Solution

Answer & Solution

Correct Answer

(D) 36.2

Step-by-step Solution

Detailed explanation

Differentiating \(I_D\) w.r.t. \(V_D\), we get \[ \begin{gathered} \frac{d}{d V_D}\left(I_D\right)=\frac{d}{d V_D}\left(7.8 \times 10^{-5} e^{6.9 V_D}\right) \\ =7.8 \times 10^{-5} \times 6.9 \times e^{6.9 V_D} \\ =I_D \times 6.9 \end{gathered} \] Dynamic resistance is…