ASSIGNMENT - II
Due Date: 15 October 2019
This assignment has 5 questions of 4 marks each for a total of 20 marks.
Submit your answers neatly written on A4 sheets.
No print-outs allowed!
  1. Start with the following equation for the reverse saturation current in p-n junction diode $$ I_0 \equiv \frac{AeD_pp_{n0}}{L_p} + \frac{AeD_nn_{p0}}{L_n} $$ show that $I_0$ is also given by $$ I_0 = AV_T\frac{b\sigma_i^2}{(1+b^2)}\left( \frac{1}{L_p\sigma_n} + \frac{1}{L_n\sigma_p}\right) $$ where $\sigma_n(\sigma_p)$ is the conductivity of the $n$($p$) side, $\sigma_i$ is the conductivity of the intrinsic material and $b = \mu_n/\mu_p$.

    2.  

  2. Draw and explain the Volt-Ampere characteristics of a Tunnel diode based on energy band diagrams.

    3.  

  3. Work out (from the textbook) the derivation of V-I characteristics of an n-p-n transistor in CE configuration. What are the simplified equations in the active region?

    4.  

  4. From the V-I characteristics of an n-p-n transistor and the circuit given below, draw its output voltage $V_{CE}$ and current $i_c$ waveforms on a graph sheet (as accurately as possible). $i_b$ is given by a triangular waveform of amplitude 0.2 mA and $V_{CC}$ = 8V.

    Choose a reasonable quiescent point Q.

       

    5.  

  5. Explain the working of junction diode based clipping circuits and show how they are useful in producing square waves (approximate!) from sinusoidal inputs.
Due Date: 15 October 2019