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Table 1: BJT DC Biasing and Stability
| Subtopic/ Sub-subtopic | Questions | Type | Year(s) |
|---|---|---|---|
| Load Line Analysis | Define load line and explain it’s significance. Explain the effect of changing the circuit elements of a fixed bias common emitter circuit on the transistor operating point. | Descriptive | 2023 |
| What is load line? Explain the effects of changing the levels of base current, collector resistance, and Vcc on the transistor operating point (Q) using the load line analysis. | Descriptive | 2017 | |
| What is load line analysis? Explain the switching operation of BJT using load line analysis. | Descriptive | 2015 | |
| Stability & Thermal Runaway | Define thermal stability in transistor amplifiers. Explain thermal runway and how it can be prevented using bias stabilization techniques. | Descriptive/Definition | 2023 |
| What is meant by thermal runaway? How does thermal runaway change the operating point of an amplifier? | Descriptive/Definition | 2022 | |
| Explain the factors that affect the stability of a transistor circuit. | Descriptive | 2022 | |
| Explain the factors that affect the stability of a transistor circuit. How does an additional emitter resistance improve the stability? Explain in brief considering the physical happenings. | Descriptive | 2021, 2017 | |
| What do you mean by bias stabilization and thermal runway? | Definition | 2019, 2015 | |
| How is the operating point of transistor affected by increase of surrounding temperature? | Descriptive | 2018 | |
| Write the mathematical expressions of stability factors and hence show that voltage divider bias configuration is the most stable. | Descriptive/Mathematical | 2018, 2015 | |
| What is meant by bias stabilization? “The Q-point of a bias circuit become more stable if an emitter resistance is connected” – Justify the statement. | Descriptive/Justification | 2016 | |
| Biasing Configurations | “Two diodes connected back to back resemble a transistor amplifier”- Explain in brief. | Descriptive | 2023 |
| “Two diodes connected back to back resemble a transistor but it cannot work as a transistor amplifier” – explain. | Descriptive | 2021, 2019 | |
| Describe the concept of mid-point biasing. | Descriptive | 2021 | |
| What is the necessity of transistor biasing? Design a fixed bias circuit in order to obtain the following load line and Q-point. [Ref Figure 1(a) with , , ] | Descriptive/Design | 2018 | |
| What is the necessity of transistor biasing? Design a fixed bias circuit in order to obtain the following load line and Q-point. [Ref Figure 1(a) with , , ] | Descriptive/Design | 2016 | |
| What is the condition for approximate analysis of voltage divider bias configuration? Determine the values of and of the following network using approximate analysis. [Ref Figure 1(d)] | Descriptive/Calculation | 2018 | |
| Design Problems | Determine , and for the emitter bias configuration of shown in figure 2(c). | Calculation | 2023 |
| Given that and , determine and for the network of Fig. 1(d). | Calculation | 2022 | |
| Determine the levels of , , and for the network of Fig. 1(d) for the operating point indicated. [Ref Figure 1(d) with , ] | Calculation | 2021, 2019 | |
| Design a voltage-divider bias network using a supply of 24V, a transistor with a beta of 110 and operating point of and . Choose . | Design | 2020 | |
| Determine the quiescent levels of and for the following network shown in figure 1(d). | Calculation | 2017 | |
| Determine and for the following voltage divider network with the operating point of and . | Calculation | 2016 | |
| Determine the values of and for the voltage divider configuration of Fig. 1(d). | Calculation | 2015 |
Table 2: BJT Small Signal Analysis
| Subtopic/ Sub-subtopic | Questions | Type | Year(s) |
|---|---|---|---|
| BJT Modeling Concepts | What is meant by BJT modeling? Write down the procedure of obtaining ac equivalent circuit of a BJT. | Definition/Descriptive | 2023, 2022, 2018 |
| Expound on the differences between small signal analysis and large signal analysis. | Comparison | 2023 | |
| What are the differences between small signal analysis and large signal analysis? What are the procedures of obtaining ac equivalent network of BJT circuits? | Comparison/Descriptive | 2019, 2016 | |
| What is the necessity of BJT modelling? Write down the advantages and disadvantages of model. | Descriptive/Comparison | 2017 | |
| What do you mean by BJT modeling? Compare model and hybrid model mentioning their advantages and disadvantages. | Comparison | 2015 | |
| Model Analysis | Derive the expression for (i) , (ii) , (iii) , and (iv) of common emitter fixed biased configuration in forms of . | Mathematical/Derivation | 2022, 2021, 2019, 2018, 2017, 2016 |
| Elucidate the significance of emitter resistor in emitter bias configuration and explain the effect of a bypass capacitor on the performance of an amplifier. | Descriptive | 2023 | |
| What is the significance of emitter resistor in emitter bias configuration? What are the effects of a bypass capacitor on the voltage gain of an amplifier? | Descriptive | 2022, 2020 | |
| For the network shown in figure 1(c), determine , , , and considering . Also, determine considering and compare the results. | Calculation | 2023, 2019 | |
| Design an amplifier circuit considering the following requirements: (i) Common emitter bias configuration, (ii) Voltage gain, (without bypass), (iii) Stability factor, . Also, explain the impact of bypass capacitor in this amplifier circuit. | Design/Descriptive | 2022 | |
| Design an amplifier circuit considering the following requirements: (i) Voltage gain, (without bypass), (ii) Stability factor, . Also, explain the impact of bypass capacitor in this amplifier circuit. | Design/Descriptive | 2021 | |
| For the network of the following figure, determine (i) , (ii) and (iii) using approximate analysis. [Ref Figure 2(b)] | Calculation | 2020 | |
| For the following network, determine: (i) , (ii) , (iii) , (iv) and (v) considering connected (bypassed) and without (un-bypassed). Also comments on the obtained voltage gain. | Calculation/Descriptive | 2018, 2017 | |
| Define -modeling. Draw the -models for common emitter and common collector configuration. | Definition/Diagram | 2016 | |
| Find the voltage gain () of the following network with and without the bypass capacitor () and comment on the obtained results. | Calculation/Descriptive | 2016 | |
| Write the merits of emitter follower configuration. Using modeling concept, derive the expression for input impedance () and output impedance () for emitter follower configuration. | Descriptive/Derivation | 2015 | |
| Determine: (a) , (b) , (c) , and (d) for the following network. [Ref Figure 2(c)] | Calculation | 2015 | |
| Hybrid Model Analysis | “The input impedance is a function of load impedance” – Justify the statement using the hybrid modeling concept. | Justification | 2022, 2021, 2017 |
| What are the advantages of hybrid model? Draw the exact and appropriate hybrid model of three common configurations. | Descriptive/Diagram | 2021, 2019, 2016 | |
| Define hybrid model and hybrid parameters. Draw the hybrid models of three different configurations of transistor. | Definition/Diagram | 2018 | |
| Define -parameters. How can you determine -parameters from transistor characteristic curves? | Definition/Descriptive | 2020, 2015 | |
| Derive the expression for , , , and for a basic transistor amplifier circuits using -parameters model. | Derivation | 2015 | |
| Darlington Pair & Multistage | Discuss the working principle of Darlington pair circuit using necessary diagram. | Descriptive | 2023, 2019 |
| What is Darlington pair circuit? Derive the expression for current gain () of Darlington pair using h-parameters and comments on the obtained expression. | Descriptive/Derivation | 2017, 2015 | |
| Derive the expression for current gain () of Darlington pair circuit using h-parameters and comments on the obtained expression. | Derivation | 2018 | |
| Determine the input impedance and overall gain of the two-stage amplifier shown in figure 4(b) using simplified model. [Ref parameters , , , ] | Calculation | 2023, 2019, 2015 | |
| A two-stage amplifier circuit (CE-CC) is shown in Fig. 3(c). [Ref parameters]. Find the input and output impedances, and overall voltage and current gains of the combined circuit. | Calculation | 2021, 2018 | |
| Determine , , , and for the following two-stage cascade network using simplified hybrid model. | Calculation | 2017 | |
| Determine the input impedance and overall voltage gain of the following two stage amplifier using simplified hybrid model. [Ref Figure 3(d)] | Calculation | 2016 |
Table 3: Field Effect Transistors (FETs)
| Subtopic/ Sub-subtopic | Questions | Type | Year(s) |
|---|---|---|---|
| BJT vs FET / Characteristics | Write down the differences between BJT and FET. | Comparison | 2023, 2017, 2016 |
| Briefly explain the reasons behind the higher input impedance of FET. | Descriptive | 2018 | |
| Distinguish between p-channel and n-channel JFET? A p-channel JFET has and . Sketch its transfer characteristics. | Comparison/Diagram | 2019, 2016 | |
| JFET Biasing (DC) | For a JFET self-bias configuration, prove that , with necessary diagram. | Derivation | 2023, 2015 |
| Determine the following parameters using the given network shown in figure 5(c): (i) , (ii) , (iii) , (iv) , (v) , (vi) and (vii) . [Voltage Divider Bias] | Calculation | 2023 | |
| Determine the following parameters in Fig. 5(b): (i) , and (ii) for the following n-channel JFET network with and . | Calculation | 2022, 2019 | |
| For the network shown in Fig. 5 (c), determine (i) , (ii) , (iii) , (iv) , (v) , and (vi) . | Calculation | 2021 | |
| Explain the voltage divider biasing of FET amplifier and consequently discuss the effect of on the resulting Q-point. | Descriptive | 2021, 2018, 2017, 2015 | |
| For the network shown in Fig. 6 (c), determine (i) , (ii) and , (iii) and , (iv) . | Calculation | 2021 | |
| Determine (i) , (ii) , (iii) , and (iv) for the common gate configuration shown in Figure 5(b). | Calculation | 2020 | |
| For the following network, determine: (i) , (ii) , (iii) , (iv) , (v) and (vi) . [Self-Bias JFET, Fig 6(c)] | Calculation | 2018, 2017, 2015 | |
| Write down the differences between self-bias and fixed bias configuration of FET. | Comparison | 2016 | |
| For the given network in Fig. 6(d), determine i) , ii) , iii) and iv) . Use appropriate transfer curve for calculation. | Calculation | 2016 | |
| JFET AC Analysis | Derive the mathematical definition of transconductance. Explain the effect of drain current on transconductance factor of FET. | Derivation/Descriptive | 2023, 2017 |
| Define transconductance (). Derive the expression of transconductance factor for JFET. | Definition/Derivation | 2020 | |
| Give the mathematical derivation of transconductance. | Derivation | 2018, 2016, 2015 | |
| Show that ; where symbols have their usual meanings. | Derivation | 2015 | |
| Prove that for common gate JFET configurations. | Derivation | 2023, 2021, 2019, 2017 | |
| For the network shown in figure 6(c), operating at and , determine (i) , (ii) , (iii) , (iv) , (v) with and without . Also give comments on the effect of on . | Calculation/Descriptive | 2023 | |
| Prove that for a self bias FET configuration voltage gain increase when bypass resistance is used. | Derivation | 2023, 2022, 2018, 2016 | |
| Derive the expression of voltage gain for self-bias configuration with unbypassed . | Derivation | 2019 | |
| For a self-bias configuration of JFET amplifier, show that the voltage gain with unbypassed is less than the voltage gain with bypassed . | Comparison/Derivation | 2015 | |
| Design the following fixed biased network to have an ac gain of 10. [Ref Figure 7(c) / 8(c)] | Design | 2022, 2019, 2018, 2015 | |
| For the following fixed-bias configuration, Determine: (i) , (ii) , (iii) , (iv) , (v) with and without . | Calculation | 2022 | |
| For the network shown in Fig. 7 (c), has an operating point and . With an applied signal , determine (i) , (ii) , (iii) , (iv) , and (iv) . | Calculation | 2021 | |
| A dc analysis of the following network (Fig. 6(b)) results in and . Determine (i) , (ii) , (iii) and (iv) without . | Calculation | 2020 | |
| Draw a JFET source follower configuration and its ac equivalent circuit. From this circuit, prove that . | Diagram/Derivation | 2019 | |
| The source follower network of the following figure has the Q-point as and . Determine: (i) , (ii) , (iii) , (iv) with and without and (v) with and without . | Calculation | 2018, 2017, 2016 | |
| Determine the following parameters for the network in Fig. 7(c); (i) , (ii) , (iii) with and without , (iv) with and without and (v) with and without . Also give your comments on the results of (iii) – (v). | Calculation/Descriptive | 2015 | |
| MOSFETs | Construct an n-channel enhancement-type MOSFET and explain its basic operation. | Descriptive | 2022 |
| Distinguish between depletion type and enhancement type MOSFET, why is the input impedance of MOSFET so high? Explain in brief. | Comparison/Descriptive | 2021, 2019 | |
| What are the differences between enhancement and depletion MOSFET? Explain the construction and operation of depletion type MOSFET using necessary diagrams. | Comparison/Descriptive | 2016 |
Table 4: Power Amplifiers
| Subtopic/ Sub-subtopic | Questions | Type | Year(s) |
|---|---|---|---|
| Concepts & Classification | “The efficiency of power amplifier increases with smaller input operating cycle”-Justify the statement with necessary diagrams. | Justification/Diagram | 2023, 2017, 2016, 2015 |
| “Power amplification is mainly a nonlinear process” – justify the statement. | Justification | 2022, 2018, 2015 | |
| Distinguish between voltage amplifier and power amplifier. | Comparison | 2021, 2019 | |
| What are the key differences between voltage amplification and power amplification concepts? Compare different classes of power amplifiers. | Comparison | 2019 | |
| Define and classify power amplifier. Why do uses of smaller input cycle provide larger efficiency in power amplifier? | Definition/Descriptive | 2016 | |
| What are the major considerations in designing power amplifier circuits? Explain in brief. | Descriptive | 2018, 2015 | |
| Push-Pull Amplifiers | Define crossover distortion. Explain the operation of a transformer coupled push-pull amplifier. | Definition/Descriptive | 2023 |
| Explain the operation of Quasi-Complementary push-pull amplifier. How does this amplifier minimize crossover distortion? | Descriptive | 2022 | |
| What is crossover distortion? Explain the operation of transformer coupled push pull power amplifier using suitable diagram. | Definition/Descriptive | 2021 | |
| Why is complementary push-pull power amplifier called so? Explain the operation of complementary push-pull power amplifier using suitable diagram. | Descriptive | 2020 | |
| Why is push-pull power amplifier called so? Explain the operation of complementary push pull power amplifier using suitable diagram. | Descriptive | 2019 | |
| Why is the push-pull power amplifier called so? Deduce the expression for maximum efficiency of push-pull power amplifier. | Descriptive/Derivation | 2018, 2017, 2015 | |
| Explain the working principle of complementary power amplifier using necessary diagram. | Descriptive | 2016 | |
| Draw the block diagram of a typical class-D power amplifier and briefly explain its operation. | Diagram/Descriptive | 2016 | |
| Efficiency & Calculation | Design a class A amplifier for maximum efficiency with the following specification: , , a load resistance of , and a turn ratio of 5. | Design | 2023 |
| For a class B amplifier using a supply of and driving a load of , determine the maximum input power and output power. | Calculation | 2021 | |
| Show that the maximum efficiency of push pull power amplifier is 78.5%. | Mathematical Proof | 2019 |
Table 5: Frequency Response and Miller Effect
| Subtopic/ Sub-subtopic | Questions | Type | Year(s) |
|---|---|---|---|
| General Response | Explain the frequency response of a common emitter amplifier and briefly discuss the impact of various capacitive element on transistor frequency response. | Descriptive | 2023 |
| Determine the lower cutoff frequency for the network for the network of Fig. 3(c) using following parameters: , , , , , , , , , , , . | Calculation | 2022 | |
| Explain the low frequency and high frequency responses of a BJT amplifier. | Descriptive | 2020 | |
| How is the frequency response varied with number of stages in multistage amplifier? Illustrates graphically. | Descriptive/Diagram | 2019, 2018, 2016 | |
| What are the components involved in low and high frequency response of bipolar junction transistor circuits? Find the frequency for each component and explain the overall frequency response using necessary diagram. | Descriptive/Calculation | 2017 | |
| Determine the high-cutoff frequencies for the network shown in Fig. 6(c) using the following parameters: , , , , , , . | Calculation | 2022 | |
| Determine the lower cut-off frequency for the network shown in Fig. 8(c) using the following parameters. [Ref JFET network]. | Calculation | 2016 | |
| Miller Effect | What is Miller capacitance? Write down the effect of Miller capacitance on the high frequency cutoff of BJT circuit. | Definition/Descriptive | 2022, 2021, 2019, 2018, 2016 |
| Define Miller effect. | Definition | 2017 |
Table 6: Specialized Electronic Circuits
| Subtopic/ Sub-subtopic | Questions | Type | Year(s) |
|---|---|---|---|
| Diode Circuits | Write short note on Clipper and Clamper. | Definition/Descriptive | 2022 |
| Draw the output waveshapes of the following clamper circuits. Assume diodes are ideal. [Ref Figure 6(d) / 8(b)] | Diagram | 2023, 2022 | |
| 555 Timer & CMOS | Describe the procedure of pulse generation using 555 timer with necessary diagrams. | Descriptive/Diagram | 2023 |
| Explain the operation of a CMOS inverter and mention the advantages of using CMOS technology. | Descriptive | 2023 | |
| Design an inverter using CMOS and explain its operation. | Design/Descriptive | 2022 | |
| Op-Amp Circuits | Design a comparator circuit that will identify whether an ac input voltage is higher or lower than 4V. | Design | 2023 |
Table 7: Display Systems and Optoelectronic Devices
| Subtopic/ Sub-subtopic | Questions | Type | Year(s) |
|---|---|---|---|
| CRT & Deflection | Prove that deflection on the screen of a Cathode Ray Tube is directly proportional to the deflecting voltage between the plates. | Mathematical Proof | 2022, 2018 |
| Prove that a cathode ray tube may be used as a linear voltage indicating device. | Mathematical Proof | 2021, 2017 | |
| “A cathode ray tube may be used as a linear voltage indicating device” – justify the statement. | Justification | 2020, 2018 | |
| Show that the electrostatic deflection sensitivity of a cathode-ray tube is , where the symbols have their usual meanings. | Mathematical Proof | 2015 | |
| Write short note on electrostatic deflection sensitivity. | Definition | 2019 | |
| Write short note on magnetic deflection and its sensitivity. | Definition | 2017 | |
| Write down the similarities between electrostatic-deflection sensitivity and magnetic-deflection sensitivity. | Comparison | 2015 | |
| Displays (LCD, OLED, etc.) | Describe the basic operation of LCD display and write its application. | Descriptive | 2023, 2022 |
| Write the advantages of LCD over CRT. Differentiate between QLED and OLED. | Comparison | 2023, 2022 | |
| Write short notes on plasma display technology. | Definition/Descriptive | 2023 | |
| What is LCD? Describe the basic operations of LCD panel. | Definition/Descriptive | 2018, 2015 | |
| Optoelectronics | Describe the basic operating principle of a solar cell. | Descriptive | 2021, 2020, 2019 |
| Describe the basic operating principle of a solar cell and write its application. | Descriptive | 2022 | |
| Briefly explain the construction and operating principle of solar cell. Also, calculate the maximum power rating of a solar cell if its conversion efficiency is 85%. | Descriptive/Calculation | 2019 | |
| Explain the construction and operating principle of a solar cell. | Descriptive | 2015 | |
| Describe the operating principle of photo-conductive cells. Also mention some practical applications of photo conductive device. | Descriptive | 2021, 2019, 2018, 2015 | |
| What is photodiode? Describe the operation and characteristics of photodiode. | Definition/Descriptive | 2019 | |
| Write short notes on (i) Photodiode, (ii) Phototransistor. | Definition | 2015 |
Table 8: Motion of Charged Particles in Electromagnetic Fields
| Subtopic/ Sub-subtopic | Questions | Type | Year(s) |
|---|---|---|---|
| Electric & Magnetic Fields | For a charged particle placed in a magnetic field, show that the period and angular velocity are independent of speed or radius. | Mathematical Proof | 2020 |
| “For a charged particle placed in a magnetic field, the period and angular velocity are independent of speed or radius?”-Justify the statement. | Justification | 2019 | |
| If a charged particle enters to a constant uniform magnetic field normally with a speed, then prove that period and angular velocity will be independent of speed or radius. | Mathematical Proof | 2016 | |
| Discuss about the path of a charged particle in presence of parallel electric and magnetic fields. | Descriptive | 2021, 2019, 2017, 2015 | |
| Give your comments about the path of a charged particle in presence of parallel electric and magnetic field. | Descriptive | 2016 | |
| Show that electron moves in a parabolic path in the region between two parallel plates of a capacitor in presence of electric filed. | Mathematical Proof | 2021, 2017, 2015 | |
| Write your idea about radius of circles generated by different particles moving with different initial velocities in a magnetic field. | Descriptive | 2018 | |
| Compare electrostatic deflection sensitivity and magnetic deflection sensitivity. | Comparison | 2016 | |
| Show that the notion electron in an electromagnetic field can be expressed as: ; ; and ; where the symbols have their usual meanings. | Mathematical Proof | 2016 |