Q1:

Which of the following options describes correctly the equilibrium band diagram at T = 300 K of a silicon pnn⁺ p⁺⁺ configuration shown in the figure?

$\begin{array}{cccc}p& n& n^{+}& p^{++}\end{array}$

Q2:

As shown, two Silicon (Si) abrupt p-n junction diodes are fabricated with uniform donor doping concentrations of $N_{D_1}$= 10¹⁴ cm^–3 and $N_{D_1}$ = 10¹⁶ cm^–3 in the n-regions of the diodes, and uniform acceptor doping concentrations of $N_{A_1}$ = 10¹⁴ cm^–3 and $N_{A_2}$ = 10¹⁶ cm^–3 in the p-regions of the diodes, respectively. Assuming that the reverse bias voltage is >> built-in potential of the diodes, the ratio $\frac{C_2}{C_1}$ of their reverse bias capacitances for the same applied reverse bias is ______.

Q3:

Red (R), Green (G) and Blue (B) Light Emitting Diodes (LEDs) were fabricated using p-n junctions of three different inorganic semiconductors having different band-gaps. The built-in voltages of red, green and blue diodes are V_R, V_G and V_B, respectively. Assumed donor and acceptor doping to be the same (N_A and N_D, respectively) in the p and n sides of all the three diodes.

Which one of the following relationships about the built-in voltages is TRUE?

Q4:

A region of negative differential resistance is observed in the current voltage characteristics of a silicon p-n junction if

Q5:

In a p-n junction diode at equilibrium, which one of the following statements is NOT TRUE?

Q6:

In the circuit shown below, the knee current of ideal zener diode is 10 mA. To maintain 5 volts across the load R_L, the minimum value of R_L in $\Omega$’s and the minimum power rating of the zener diode in mW respectively are

Q7:

The ripple factor in a full wave rectifier without filter is

Q8:

Consider the following rectifier circuits

1. Have – wave rectifier without filter.

2. Full – wave rectifier without filter.

3. Full – wave rectifier with series inductance filter.

4. Full – wave rectifier with capacitance filter.

The sequence of these rectifier circuits in decreasing order of their ripple factor is.

Q9:

The use of a rectifier circuit in a capacitor filter gives satisfactory performance only when the load

Q10:

The PIV rating of the diodes used in power supply circuits are chosen by which one of the following criteria?

Q11:

Silicon diodes are less suitable for low voltage rectifier operation because.

Q12:

The ripple frequency in a full wave rectifier is…………..that of the supply frequency.