Semiconductor Devices - Electronics - Physics Previous Year Questions

1

2007 · Physics · Electronics · Semiconductor Devices

Physics (PH) 2007

In a typical \(npn\) transistor the doping concentrations in emitter, base and collector regions are \(C_E, C_B\) and \(C_C\) respectively. These satisfy the relation,

A

\(C_E > C_C > C_B\)

B

\(C_E > C_B > C_C\)

C

\(C_C > C_B > C_E\)

D

\(C_E = C_C > C_B\)

Open complete paper

2

2007 · Physics · Electronics · Semiconductor Devices

Physics (PH) 2007

In a typical \(npn\) transistor the doping concentrations in emitter, base and collector regions are \(C_E\), \(C_B\) and \(C_C\) respectively. These satisfy the relation,

A

\(C_E > C_C > C_B\)

B

\(C_E > C_B > C_C\)

C

\(C_C > C_B > C_E\)

D

\(C_E = C_C > C_B\)

Open complete paper

3

2007 · Physics · Electronics · Semiconductor Devices

Physics (PH) 2007

In the circuit shown, the voltage at test point P is 12 V and the voltage between gate and source is -2V. The value of R (in kΩ) is

A

42

B

48

C

56

D

70

Open complete paper

4

2007 · Physics · Electronics · Semiconductor Devices

Physics (PH) 2007

When an input voltage V_i of the form shown, is applied to the circuit given below, the output voltage V_o is of the form

A

12 V / 0 V

B

12 V / 3 V / 0 V

C

12 V / 2.3 V / 0 V

D

0 V / -12 V

Open complete paper

5

2007 · Physics · Electronics · Semiconductor Devices

Physics (PH) 2007

In the circuit shown, the voltage at test point P is 12 V and the voltage between gate and source is -2V. The value of \( R \) (in \( k\Omega \)) is

A

42

B

48

C

56

D

70

Open complete paper

6

2007 · Physics · Electronics · Semiconductor Devices

Physics (PH) 2007

When an input voltage \( V_i \) of the form shown, is applied to the circuit given below, the output voltage \( V_o \) is of the form

A

12 V, 0 V

B

12 V, 3 V, 0 V

C

12 V, 2.3 V, 0 V

D

0 V, -12 V

Open complete paper

7

2008 · Physics · Electronics · Semiconductor Devices

Physics (PH) 2008

A common emitter transistor amplifier circuit is operated under a fixed bias. In this circuit, the operating point

A

remains fixed with an increase in temperature.

B

moves towards cut-off region with an increase in temperature.

C

moves towards the saturation region with a decrease in temperature.

D

moves towards the saturation region with an increase in temperature.

Open complete paper

8

2008 · Physics · Electronics · Semiconductor Devices

Physics (PH) 2008

Under normal operating conditions, the gate terminal of an n-channel junction field effect transistor (JFET) and an n-channel metal oxide semiconductor field effect transistor (MOSFET) are

A

both biased with positive potentials.

B

both biased with negative potentials.

C

biased with positive and negative potentials, respectively.

D

biased with negative and positive potentials, respectively.

Open complete paper

9

2008 · Physics · Electronics · Semiconductor Devices

Physics (PH) 2008

An a.c. voltage of 220 \(V_{rms}\) is applied to the primary of a 10:1 step-down transformer. The secondary of the transformer is centre tapped and connected to a full wave rectifier with a load resistance. The d.c. voltage appearing across the load is

A

\(\frac{22}{\pi}\) V

B

\(\frac{31}{\pi}\) V

C

\(\frac{62}{\pi}\) V

D

\(\frac{44}{\pi}\) V

Open complete paper

10

2009 · Physics · Electronics · Semiconductor Devices

Physics (PH) 2009

Pick the correct statement based on the above circuit.

A

The maximum Zener current, I_Z(max), when R_L = 10 kΩ is 15 mA

B

The minimum Zener current, I_Z(min), when R_L = 10 kΩ is 5 mA

C

With V_in = 20V, I_L = I_Z, when R_L = 2 kΩ

D

The power dissipated across the Zener when R_L = 10 kΩ and V_in = 20 V is 100 mW

Open complete paper

11

2011 · Physics · Electronics · Semiconductor Devices

Physics (PH) 2011

In the following circuit, the voltage across and the current through the \(2\text{ k}\Omega\) resistance are

A

20 V, 10 mA

B

20 V, 5 mA

C

10 V, 10 mA

D

10 V, 5 mA

Open complete paper

12

2011 · Physics · Electronics · Semiconductor Devices

Physics (PH) 2011

In the following circuit, the voltage across and the current through the \(2\ k\Omega\) resistance are

A

20 V, 10 mA

B

20 V, 5 mA

C

10 V, 10 mA

D

10 V, 5 mA

Open complete paper

13

2011 · Physics · Electronics · Semiconductor Devices

Physics (PH) 2011

In the following circuit, Tr1 and Tr2 are identical transistors having \(V_{BE} = 0.7\ \text{V}\). The current passing through the transistor Tr2 is

A

57 mA

B

50 mA

C

48 mA

D

43 mA

Open complete paper

14

2011 · Physics · Electronics · Semiconductor Devices

Physics (PH) 2011

Consider the following circuit. Which of the following correctly represents the output \(V_{out}\) corresponding to the input \(V_{in}\)?

A

graph

B

graph

C

graph

D

graph

Open complete paper

15

2012 · Physics · Electronics · Semiconductor Devices

Physics (PH) 2012

If the peak output voltage of a full wave rectifier is 10 V, its d.c. voltage is

A

10.0 V

B

7.07 V

C

6.36 V

D

3.18 V

Open complete paper

16

2012 · Physics · Electronics · Semiconductor Devices

Physics (PH) 2012

Consider the following circuit in which the current gain \(\beta_{dc}\) of the transistor is 100. Which one of the following correctly represents the load line (collector current \(I_C\) with respect to collector-emitter voltage \(V_{CE}\)) and Q-point of this circuit?

A

Graph with Q-point at (2 V, 13 mA) and load line from 15 V to 15 mA

B

Graph with Q-point at (2 V, 10 mA) and load line from 15 V to 13 mA

C

Graph with Q-point at (7.5 V, 7.5 mA) and load line from 15 V to 15 mA

D

Graph with Q-point at (7.5 V, 6.5 mA) and load line from 15 V to 13 mA

Open complete paper

17

2013 · Physics · Electronics · Semiconductor Devices

Physics (PH) 2013

An $n$-channel junction field effect transistor has $5mA$ source to drain current at shorted gate ($I_{DSS}$) and $5V$ pinch off voltage ($V_P$). Calculate the drain current in $mA$ for a gate-source voltage ($V_{GS}$) of $-2.5V$. The answer should be up to two decimal places.

Check answer

Open complete paper

18

2014 · Physics · Electronics · Semiconductor Devices

Physics (PH) 2014

The current gain of the transistor in the following circuit is \(\beta_{dc} = 100\). The value of collector current \(I_c\) is __________ mA.

Check answer

Open complete paper

19

2016 · Physics · Electronics · Semiconductor Devices

Physics (PH) 2016

For the transistor shown in the figure, assume \( V_{BE} = 0.7 \) V and \( \beta_{dc} = 100 \). If \( V_{in} = 5 \)V, \( V_{out} \) (in Volts) is ______. (Give your answer upto one decimal place)

Check answer

Open complete paper

20

2017 · Physics · Electronics · Semiconductor Devices

Physics (PH) 2017

In the figure given below, the input to the primary of the transformer is a voltage varying sinusoidally with time. The resistor R is connected to the centre tap of the secondary. Which one of the following plots represents the voltage across the resistor R as a function of time?

A

B

C

D

Open complete paper