Instructions:
- The marks are indicated in the right-hand margin.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
Q.1 Answer the following questions (any seven only):
Mention the advantages of Full Wave Rectifier.
Draw the pn junction diode VI characteristics.
What are the different configurations of BJT?
What is stability factor?
What is MOSFET? Classify the types of MOSFET
What is meant by pinchoff voltage?
Define an operational amplifier.
Define Slew rate.
Mention some of the non-linear applications of op-amp.
List the features of instrumentation amplifier.
Q.2 Solve both questions :
What is a PN Junction? Explain the formation of depletion layer in a PN junction.
Draw the circuit diagram of half wave rectifier and explain its operation with the help of waveforms.
Q.3 Solve both questions :
If the base current in a transistor is 20 $ \mu A $ when the emitter current is 6.4mA, what are the values of $ \alpha $ and $ \beta $? Also calculate the collector current.
Why hybrid model is used for the analysis of BJT amplifier at low frequencies? Draw the hybrid model for CE transistor and derive the parameters.
Q.4 Solve both questions :
With the help of neat diagram, explain the operation and characteristics of n-channel enhancement type MOSFET.
Draw and explain the small signal model of FET at low frequency.
Q.5 Solve both questions :
What are the factors that affect the frequency stability of an oscillator? How can be improved in oscillators.
Compare different configurations of differential amplifier.
Q.6 Solve both questions :
Write the design steps of the first order low pass filter and draw its circuit.
With the help of neat and clear sketch, explain the working of a MOS transistor as a switch.
Q.7 Solve this question :
Explain the basic building block diagram of an op-amp. Write short note on input bias current, output bias current, slew rate and output offset voltage of an op-amp.
Q.8 Solve both questions :
Explain the working of series clipping circuit to clip the input sinusoidal signal above reference level. Draw the waveforms and transfer characteristics.
Compare BJT and FET on different parameters.
Q.9 Solve both questions :
Write Short notes on (i) Zero Crossing Detector (ii) Precision Rectifier
Explain the function of Square-wave and triangular-wave generators.
Instructions:
- The marks are indicated in the right-hand margin.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
Q.1 Answer the following questions (any seven only):
Mention the advantages of Full Wave Rectifier.
Draw the pn junction diode VI characteristics.
What are the different configurations of BJT?
What is stability factor?
What is MOSFET? Classify the types of MOSFET
What is meant by pinchoff voltage?
Define an operational amplifier.
Define Slew rate.
Mention some of the non-linear applications of op-amp.
List the features of instrumentation amplifier.
Q.2 Solve both questions :
What is a PN Junction? Explain the formation of depletion layer in a PN junction.
Draw the circuit diagram of half wave rectifier and explain its operation with the help of waveforms.
Q.3 Solve both questions :
If the base current in a transistor is 20 $ \mu A $ when the emitter current is 6.4mA, what are the values of $ \alpha $ and $ \beta $? Also calculate the collector current.
Why hybrid model is used for the analysis of BJT amplifier at low frequencies? Draw the hybrid model for CE transistor and derive the parameters.
Q.4 Solve both questions :
With the help of neat diagram, explain the operation and characteristics of n-channel enhancement type MOSFET.
Draw and explain the small signal model of FET at low frequency.
Q.5 Solve both questions :
What are the factors that affect the frequency stability of an oscillator? How can be improved in oscillators.
Compare different configurations of differential amplifier.
Q.6 Solve both questions :
Write the design steps of the first order low pass filter and draw its circuit.
With the help of neat and clear sketch, explain the working of a MOS transistor as a switch.
Q.7 Solve this question :
Explain the basic building block diagram of an op-amp. Write short note on input bias current, output bias current, slew rate and output offset voltage of an op-amp.
Q.8 Solve both questions :
Explain the working of series clipping circuit to clip the input sinusoidal signal above reference level. Draw the waveforms and transfer characteristics.
Compare BJT and FET on different parameters.
Q.9 Solve both questions :
Write Short notes on (i) Zero Crossing Detector (ii) Precision Rectifier
Explain the function of Square-wave and triangular-wave generators.
Instructions:
- The marks are indicated in the right-hand margin.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
Q.1 Attempt any seven from the following:
What is avalanche multiplication?
Compare CE, CC and CB for current gain, voltage gain, input and output impedance.
Junction transistor is an active device. Justify.
Write the equation of a diode and draw its VI characteristics.
What is early effect in bipolar junction transistors?
Draw an npn transistor in CB configuration and draw its input characteristics.
BJT has higher driving capability as compared to MOSFET. Justify.
For an ideal negative feedback configuration, there is a virtual short circuit between the input terminals. Why?
Draw a circuit which can be used as limiter or clamper or both.
Q.2 Solve both questions :
Write brief notes on: (i) Avalanche breakdown (ii) Zener breakdown
The saturation currents of the diodes are 1 $ \mu A $ and 2 $ \mu A $. The breakdown voltages of the diodes are the same and are equal to 100 V: (i) Calculate the current and voltage for each diode if V = 90 V and V = 110 V (ii) Repeat part (i) if each diode is shunted by 10 M$ \Omega $ resistor.
Q.3 Solve both questions :
With reference to rectifying circuits, explain- (i) ripple factor ($ \gamma $); (ii) transformer utility factor (TUF); (iii) peak inverse voltage (PIV); (iv) rectifier efficiency ($ \eta $).
For HW rectifier and capacitor filter- (i) draw the circuit diagram; (ii) draw the waveforms; (iii) give a brief explanation of the functioning of the circuit.
Q.4 Solve both questions :
Draw Ebers Moll model for pnp transistor and show that transistor action is not possible by connecting two diodes back to back.
For the transistor shown below, $ \alpha = 0.98 $ and $ V_{BB} = 0.7 $, find $ R_1 $ for an emitter current $ I_E = -2 mA $. Neglect $ I_{CO} $.
Q.5 Solve both questions :
Given the following measurements made at $ I_C = 5 mA $, $ V_{CE} = 10 V $ and at room temperature $ h_{fe} = 100 $, $ h_{ie} = 600 \Omega $, $ A_{ie} = 10 $ at 10 MHz, $ C_C = 3 pF $. Find $ f_T $, $ f_\alpha $, $ r_{b'e} $ and $ r_{bb'} $ for the transistor.
A silicon transistor with $ \beta = h_{FE} = 100 $, $ V_{BE}(sat) = 0.8V $, $ V_{CE}(sat) = 0.2 V $ is used in the circuit shown. Find the minimum value of $ R_C $ for which transistor remains in saturation.
Q.6 Solve both questions :
Compare the performance of MOSFET and BJT.
Explain the construction of p-channel MOSFET. Draw and explain both depletion and enhancement mode MOSFET.
Q.7 Solve both questions :
Calculate $ v_0 $ and the op-amp's output current as shown in the circuit and if $ E_i $ equals (i) +5 V and (ii) -2 V. For each situation, state if the op-amp sources or sinks current.
(i) Design an inverting amplifier with a gain of -5 and an input resistance of 10 k$ \Omega $. (ii) Design a non-inverting amplifier with a gain of 5.
Q.8 Solve both questions :
The circuit shown is required to supply on average voltage of 120 V. Determine the r.m.s. value of secondary voltage, average current delivered to the load, peak current through each diode and PIV of diodes.
Explain different amplifiers with suitable example.
Q.9 Write short notes on the following:
Precision comparator
Zero crossing detector with hysteresis
Instructions:
- The marks are indicated in the right-hand margin.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
Q.1 Attempt any seven from the following:
What is avalanche multiplication?
Compare CE, CC and CB for current gain, voltage gain, input and output impedance.
Junction transistor is an active device. Justify.
Write the equation of a diode and draw its VI characteristics.
What is early effect in bipolar junction transistors?
Draw an npn transistor in CB configuration and draw its input characteristics.
BJT has higher driving capability as compared to MOSFET. Justify.
For an ideal negative feedback configuration, there is a virtual short circuit between the input terminals. Why?
Draw a circuit which can be used as limiter or clamper or both.
Q.2 Solve both questions :
Write brief notes on: (i) Avalanche breakdown (ii) Zener breakdown
The saturation currents of the diodes are 1 $ \mu A $ and 2 $ \mu A $. The breakdown voltages of the diodes are the same and are equal to 100 V: (i) Calculate the current and voltage for each diode if V = 90 V and V = 110 V (ii) Repeat part (i) if each diode is shunted by 10 M$ \Omega $ resistor.
Q.3 Solve both questions :
With reference to rectifying circuits, explain- (i) ripple factor ($ \gamma $); (ii) transformer utility factor (TUF); (iii) peak inverse voltage (PIV); (iv) rectifier efficiency ($ \eta $).
For HW rectifier and capacitor filter- (i) draw the circuit diagram; (ii) draw the waveforms; (iii) give a brief explanation of the functioning of the circuit.
Q.4 Solve both questions :
Draw Ebers Moll model for pnp transistor and show that transistor action is not possible by connecting two diodes back to back.
For the transistor shown below, $ \alpha = 0.98 $ and $ V_{BB} = 0.7 $, find $ R_1 $ for an emitter current $ I_E = -2 mA $. Neglect $ I_{CO} $.
Q.5 Solve both questions :
Given the following measurements made at $ I_C = 5 mA $, $ V_{CE} = 10 V $ and at room temperature $ h_{fe} = 100 $, $ h_{ie} = 600 \Omega $, $ A_{ie} = 10 $ at 10 MHz, $ C_C = 3 pF $. Find $ f_T $, $ f_\alpha $, $ r_{b'e} $ and $ r_{bb'} $ for the transistor.
A silicon transistor with $ \beta = h_{FE} = 100 $, $ V_{BE}(sat) = 0.8V $, $ V_{CE}(sat) = 0.2 V $ is used in the circuit shown. Find the minimum value of $ R_C $ for which transistor remains in saturation.
Q.6 Solve both questions :
Compare the performance of MOSFET and BJT.
Explain the construction of p-channel MOSFET. Draw and explain both depletion and enhancement mode MOSFET.
Q.7 Solve both questions :
Calculate $ v_0 $ and the op-amp's output current as shown in the circuit and if $ E_i $ equals (i) +5 V and (ii) -2 V. For each situation, state if the op-amp sources or sinks current.
(i) Design an inverting amplifier with a gain of -5 and an input resistance of 10 k$ \Omega $. (ii) Design a non-inverting amplifier with a gain of 5.
Q.8 Solve both questions :
The circuit shown is required to supply on average voltage of 120 V. Determine the r.m.s. value of secondary voltage, average current delivered to the load, peak current through each diode and PIV of diodes.
Explain different amplifiers with suitable example.
Q.9 Write short notes on the following:
Precision comparator
Zero crossing detector with hysteresis
Instructions:
- The marks are indicated in the right-hand margin.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
- Symbols and notations carry their usual meanings.
Q.1 Answer any seven questions of the following:
What is the function of clamping circuits?
Explain diode positive shunt clipper circuit with waveforms.
Explain the half-wave rectifier with suitable diagram.
What is integrator circuit?
Write down the three differences between BJT and JFET.
Explain the important characteristics of Darlington emitter-follower.
What is precision rectifier circuit?
What are the advantages of h-parameters?
Q.2 Attempt any two parts from each :
Derive the expression for stability factor for fix bias circuit with respect to $ I_{CO} $, $ V_{BE} $ and $ \beta $.
State and prove Miller's theorem.
A voltage divider biased circuit has $ R_1=39k\Omega $, $ R_2=82 k\Omega $, $ R_C=3.3k\Omega $, $ R_E=1k\Omega $ and $ V_{CC}=18V $. The silicon transistor has used $ \beta=120 $ Find Q-point and stability factor.
Q.3 Attempt any two parts from each :
An op-amp has gain bandwidth product of 15 MHz. Determine the bandwidth of op-amp when $ A_{CL}=500 $. Also, find the maximum value of $ A_{CL} $ when frequency is 200 KHz.
What are the advantages and features of instrumentation amplifier? Derive the expression for output voltage of instrumentation amplifier.
The data sheet of N-channel JFET gives the following details: $ I_{DSS}=9mA $ and pinch-off voltage = -4.5V (i) At what value of $ V_{GS} $ will $ I_D $ be equal to 3 mA? (ii) What is its $ g_m $ at this $ I_D $?
Q.4 Attempt any two parts from each :
Derive an expression for input impedance voltage gain, current gain and output impedance for an emitter-follower circuit using h-parameter model for the transistor.
Explain the need of cascading amplifier. Draw and explain the block diagram of two-stage cascade amplifier.
Derive an expression for frequency of oscillators in Wien bridge oscillator.
Q.5 Attempt any two parts from each :
Explain the principle of operation of oscillator and effect of loop gain (A$ \beta $) on the output of oscillator.
With the help of neat diagram, explain the construction working and characteristics of N-channel depletion-type MOSFET.
A given amplifier arrangement has the following voltage gains: $ A_{v1}=10 $, $ A_{v2}=20 $ and $ A_{v3}=40 $. Calculate the overall voltage gain and determine the total voltage gain in dB.
Q.6 Attempt any two parts from each :
Determine $ Z_{in} $, $ Z_{out} $ and $ A_v $ for JFET common source amplifier with fixed bias configuration using AC equivalent small signal model.
With the help of neat diagram, explain the construction working and characteristics of N-channel JFET.
Explain the law frequency response of single-stage RC-coupled amplifier.
Q.7 Attempt any two parts from each :
Obtain an h-parameter equivalent circuit of CB and CE configurations.
With the help of block diagram, explain the concept of feedback.
Discuss with the help of circuit example, the purpose of providing- (i) negative feedback; (ii) positive feedback in amplifier.
Q.8 Attempt any two parts from each :
Draw the high frequency equivalent circuit of an emitter follower and derive the expression of upper cut-off frequency $ f_H $.
Transistor's short circuit current gain is measured to be 25 at a frequency of 2 MHz. If $ f_\beta=200 $ kHz, calculate the following: (i) The current gain bandwidth product (ii) $ h_{fe} $ at low frequency (iii) Short circuit current gain at 10 MHz and 100 MHz.
A phase-shift oscillator uses three identical R-C sections in feedback network. The value of components are $ R=100 K\Omega $ and $ C=0.01 \mu F $. Calculate the frequency of oscillator.
Q.9 Attempt any two parts from each :
An amplifier has a voltage gain of 40. The amplifier is now modified to provide a 10% negative feedback in series with the input. Determine the following: (i) Voltage gain with feedback (ii) Amount of feedback in dB (iii) Loop gain.
Write the important advantage of a negative feedback amplifier and show that how bandwidth of an amplifier increases with negative feedback.
What is transistor biasing? Explain emitter bias circuit with relevant circuit and equations.
Instructions:
- The marks are indicated in the right-hand margin.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
- Symbols and notations carry their usual meanings.
Q.1 Answer any seven questions of the following:
What is the function of clamping circuits?
Explain diode positive shunt clipper circuit with waveforms.
Explain the half-wave rectifier with suitable diagram.
What is integrator circuit?
Write down the three differences between BJT and JFET.
Explain the important characteristics of Darlington emitter-follower.
What is precision rectifier circuit?
What are the advantages of h-parameters?
Q.2 Attempt any two parts from each :
Derive the expression for stability factor for fix bias circuit with respect to $ I_{CO} $, $ V_{BE} $ and $ \beta $.
State and prove Miller's theorem.
A voltage divider biased circuit has $ R_1=39k\Omega $, $ R_2=82 k\Omega $, $ R_C=3.3k\Omega $, $ R_E=1k\Omega $ and $ V_{CC}=18V $. The silicon transistor has used $ \beta=120 $ Find Q-point and stability factor.
Q.3 Attempt any two parts from each :
An op-amp has gain bandwidth product of 15 MHz. Determine the bandwidth of op-amp when $ A_{CL}=500 $. Also, find the maximum value of $ A_{CL} $ when frequency is 200 KHz.
What are the advantages and features of instrumentation amplifier? Derive the expression for output voltage of instrumentation amplifier.
The data sheet of N-channel JFET gives the following details: $ I_{DSS}=9mA $ and pinch-off voltage = -4.5V (i) At what value of $ V_{GS} $ will $ I_D $ be equal to 3 mA? (ii) What is its $ g_m $ at this $ I_D $?
Q.4 Attempt any two parts from each :
Derive an expression for input impedance voltage gain, current gain and output impedance for an emitter-follower circuit using h-parameter model for the transistor.
Explain the need of cascading amplifier. Draw and explain the block diagram of two-stage cascade amplifier.
Derive an expression for frequency of oscillators in Wien bridge oscillator.
Q.5 Attempt any two parts from each :
Explain the principle of operation of oscillator and effect of loop gain (A$ \beta $) on the output of oscillator.
With the help of neat diagram, explain the construction working and characteristics of N-channel depletion-type MOSFET.
A given amplifier arrangement has the following voltage gains: $ A_{v1}=10 $, $ A_{v2}=20 $ and $ A_{v3}=40 $. Calculate the overall voltage gain and determine the total voltage gain in dB.
Q.6 Attempt any two parts from each :
Determine $ Z_{in} $, $ Z_{out} $ and $ A_v $ for JFET common source amplifier with fixed bias configuration using AC equivalent small signal model.
With the help of neat diagram, explain the construction working and characteristics of N-channel JFET.
Explain the law frequency response of single-stage RC-coupled amplifier.
Q.7 Attempt any two parts from each :
Obtain an h-parameter equivalent circuit of CB and CE configurations.
With the help of block diagram, explain the concept of feedback.
Discuss with the help of circuit example, the purpose of providing- (i) negative feedback; (ii) positive feedback in amplifier.
Q.8 Attempt any two parts from each :
Draw the high frequency equivalent circuit of an emitter follower and derive the expression of upper cut-off frequency $ f_H $.
Transistor's short circuit current gain is measured to be 25 at a frequency of 2 MHz. If $ f_\beta=200 $ kHz, calculate the following: (i) The current gain bandwidth product (ii) $ h_{fe} $ at low frequency (iii) Short circuit current gain at 10 MHz and 100 MHz.
A phase-shift oscillator uses three identical R-C sections in feedback network. The value of components are $ R=100 K\Omega $ and $ C=0.01 \mu F $. Calculate the frequency of oscillator.
Q.9 Attempt any two parts from each :
An amplifier has a voltage gain of 40. The amplifier is now modified to provide a 10% negative feedback in series with the input. Determine the following: (i) Voltage gain with feedback (ii) Amount of feedback in dB (iii) Loop gain.
Write the important advantage of a negative feedback amplifier and show that how bandwidth of an amplifier increases with negative feedback.
What is transistor biasing? Explain emitter bias circuit with relevant circuit and equations.