eca course file - 2 yr
TRANSCRIPT
SREENIDHI INSTITUTE OF SCIENCE & TECHNOLOGYYamnampet, Ghatkesar, Hyderabad – 501 301.
Department of ECE
COURSE FILE
for
“Electronic Circuit Analysis”
II/IV B.Tech ECE – I Semester
SYLLABUS
ELECTRONIC CIRCUIT ANALYSIS
UNIT-1: SINGLE STAGE AMPLIFIERS:Classification of amplifiers – Design of single stage amplifiers,jfet amplifiers(cd,cg,cs), Bandwidth Product, Specifications of amplifiers.
UNIT-II: MULTISTAGE AMPLIFIERS: Cascaded amplifiers, analysis and design (all configurations of BJT and FET to be considered), BW of multistage of amplifiers.
UNIT-III:HIGH FREQUENCY TRANSISTOR CIRCUITS:__________________________________________________Transistor at high frequencies,hybrid- conductances,var of parameters w.r.t Ic,Vce,temp.,current gain,ce short circuit current gain,Ilvar wrt to voltage,current,temp.Design of high freq amplifier.
UNIT-IV: POWER AMPLIFIERS:ClassA power amplifier, max. value of eff of Class A amp, push pull and complimentary push pull amplifiers – Design of heat sinks, power output, efficiency, cross-over distortion and harmonic distortion,transformer coupled amplifiers,class D operation,class S operation.
UNIT-V: TUNED AMPLIFIERS-I:Single tuned capacitive coupled amplifier, CE double tuned Amplifier,Application of tuned amplifiersand stagger tuned voltage amplifiers.
UNIT-VI:TUNED AMPLIFIERS-II: stagger tuned voltage amplifiers,stability considerations,tuned class b & class c Amplifiers,Wideband Amplifiers,Tuned Amplifiers.
UNIT-VII:VOLTAGE REGULATORS:Terminology,Basic regulator circuit,short circuit protection,Current limiting,Specifications of voltage regulator circuits,voltage Multipliers.
UNIT-VIII:SWITCHING AND IC VOLTAGE REGULATORS:Voltage Multipliers,Ic723 voltage regulators, switching regulators, three terminal IC regulators, Adj. I.C. regulators,dc to dc convertor,UPS,SMPS.
TEXT BOOKS:1. Integrated Electronics – by J.Millman and G.C. Halkias, McGraw-Hill.2. Electronic Devices and Circuits – by Y.N.Bapat, TMH.3. Electronic Devices and Circuits – by K.Lal Kishore, BS Publ.4. Electronic Circuit Analysis and Design – by Donald A. Neaman, McGraw Hill.
REFERENCES:1. Micro Electronic Circuits – by Serda A.S. and K.C.Smith, Oxford University
Press2. Micro Electronic Circuits: Analysis and Design – by M.H. Rashid, PWS
Publications.
LECTURE SCHEDULE UNITS TOPICS COVERED NO. OF PERIODS
1Single stage
Amplifier
Introduction to ECA 1Small signal analysis of junction transistor, frequency response of CE,CB,CC amplifier.
2
Frequency response of JFET,CD,CG amplifier
2
GBW concept 12
Multi stage Amplifier
Multi stage a methods of inter stage coupling, n –stage cascaded amplifier.
1
Equivalent circuits, Miller’s theorem, Frequency effects, Amplifier analysis.
2
High input resistance transistor circuits 1Cascode – transistor configuration. CE – CC amplifiers.
2
Two stage RC coupled JFET amplifiers. CS configuration CS , difference amplifier.
1
3High
frequency transistor circuits
Transistor at high frequencies, Hybrid - common emitter trans conductance mode, Determination of Hybrid - conductance.
2
Variation of hybrid parameters with Ic, Vce and temperature.
2
The parameters I expression for Ib, current gain with resistance Load, CE short circuit current gain.
2
Variation of Hybrid parameters with voltage , current and temperature.
1
4Power
Amplifiers
Class A power Amplifier, Maximum value of Efficiency of class A Amplifier
1
Transformer coupled amplifier. Transformer coupled audio amplifier.
1
Push pull amplifier,. Complementary symmetry circuits
1
Phase inverters, Class D and S operation 2
Heat sink 1
5 Tuned
amplifiersI
Single tuned capacitive coupled amplifier. 1Tapped single tuned capacitive coupled amplifier.
1
Single tuned transformer coupled or inductively coupled amplifier
1
Double tuned amplifer 2Application of tuned amplifers 1
6Tuned
amplifers II
Stagger tunning, stability considerations. 2Tuned class B and Class C amplifers 2Wideband amplifiers 1Tuned amplifiers 1
7Voltage
Reglators
Terminology 1Basic regulator circuit 1Short circuit protection 1Current limiting 1Specification of Voltage Regulator Circuits 1Voltage Multipliers 1
8Switching
and IC Voltage
Regulators
IC 723 voltage regulators and Three terminal IC regulators.
2
DC to DC converters 1Switching Regulators 1Voltage Multipliers 1UPS, SMPS 1
Unit – I
SINGLE STAGE AMPLIFIERS
ESSAY TYPE QUESTIONS:
1. Describe the general frequency response of an amplifier and define the low frequency, mid frequency and high frequency ranges?
2. Draw the small signal high frequency CE model of a transistor (Hybrid- Model) and mention the parameter values at room temperature.
3. (a). What is the physical origin of two capacitors in the hybrid- model? (b). What is the order of the magnitude of each capacitance?
4. Derive the necessary expression for the resistive components of the hybrid - model i.e., gm, rb1e, rbb1, rb1c and gce in terms of CE h-parameters at low frequencies at a given IC.
5. (a) How does Ce vary with and ?(b) How does CC vary with and ?
6. (a) Derive the expression for the CE short circuit current gain A i as a function of frequency?
(b) From this result derive expression for f and fT.7. Describe the Miller effect and miller capacitance? What effect does the Miller
Capacitance have on the amplifier Band Width?8. (a) Consider a CE stage with resistance load RL. Using Miller’s Theorem
what is mid bad input capacitance?(b). Assuming the output time constant is small compared to input time constant, what is high 3dB frequency (fH) for the current gain?
9. Explain why the 3dB frequency for current gain is not same as fH for voltage gain?
10. Draw the small signal equivalent circuit for an Emitter follower stage at high frequencies.
11. The following low-frequency parameters are known for a given transistor at IC=10mA, VCE=10V and at room temperature hie=500, hoe=4 X 10-5 A/V, hfe=100, hre=10-4. At the same operating point, fT=50MHz and C0b=3PF, compute all values of the hybrid- parameters.
12. Given the following transistor measurement made at IC=5mA, VCE=10V and at room temperature.hfe = 100 hie = 600
= 10 at 10MHz CC = 3PF Find f, fT, Ce, rb1e and 1.
13. Given a germanium p-n-p transistor where bandwidth is 10-4cm. At room temperature and for a dc emitter current of 2mA, find (a) Emitter Diffusion Capacitance (b) fT.
14. The hybrid - parameters of the transistor are given as follows:gm = 50mA/V rbb
1=100, rb1e = 1K, rb1c = 4M, rce = 80 K, CC=3PF Ce=100PF. For the following circuit using Miller Theorem and the approximate analysis, compute (a) The upper 3dB frequency of the current gain AI=IL/Ii.
(b). at the frequency of part (a).
15. For a single stage CE transistor amplifier whose hybrid parameters have the values as in above problem (14); what value of Source Resistant RS will have a 3-dB frequency only fH, which is (a) Half the value for RS=0 (b) Twice the value for RS = ? Do the values of RS depend upon the magnitude of RL? Hint: Use Miller Theorem.
16. A transistor’s short-circuit current gain is measured to be 25 at a frequency of 2MHz. If the transistor’s f=200 KHz, determine:(a) The current – gain Bandwidth product(b) The transistor’s hfe at low frequencies(c) The short circuit current gain at 10MHz and 100MHz
17. (a) Sketch the small-signal high frequency circuit of CS amplifier (b) Derive the expression for the Voltage gain.
18. (a) From the CS amplifier at high frequency derive the input admittance (b) What is the expression for the input capacitance in the audio range.
19. (a) Sketch the small signal high frequency model of CD amplifier. (b) Derive the expression for the voltage gain.
20. Repeat the above problem for Source follower circuit.
+
-vs
Ii
VCC
V0
900
1KIL
+
-vs
Ii
VCC
V0
900
1KIL
Unit - ISingle Stage Amplifiers
QUIZ TYPE QUESTIONS:
1. What are the various types of an amplifier?2. What are and cut-off frequencies?3. Mention the influence of coupling capacitor CC on low frequency response.4. Which component of RC coupled amplifier is mainly responsible for the fall
of gain in low frequency range?(a). Transistor (b) Coupling Capacitor (c) Gridlock resistor (d) Stray Shunt Capacitance
5. What is meant by the term ‘Rise time’? How would you measure an amplifier’s rise time?
6. How would you expect gm to vary with temperature? Why?7. Distinguish between fT and f.8. Mention typical Magnitudes for the elements of hybrid- model at room
temperature and for IC =1.3 mA.9. Write the expression for Ce in terms of fT and gm.10. How rbb1 change with and temperature?11. Define the terms Bandwidth and gain bandwidth product.12. Express hybrid- model elements in terms of h-parameters at low frequencies
for a given IC.13. Mention the frequency range in which hybrid model is valid.14. In terms of what four parameters is the high frequency response of CE stage
obtained?15. How does Ce vary with and ?16. How does CC vary with and ?
17. How does hie vary with assuming rbb1 << rb1e.
18. Draw the small signal equivalent circuit for an emitter follower stage at high frequency.
19. Why common collector configuration finds wide application as a buffer?20. What is Miller Effect?
UNIT - IIMULTISTAGE AMPLIFIERS
ESSAY QUESTIONS:
1) Sketch the step response of a low pass single pole amplifier. (b) Define the rise time tr (c) Give the relationship between tr and high 3-dB frequency fH.
2) Derive the expression for the high 3-dB frequency fH* of cascade amplifier having n-identical non inter-acting stages in terms of fH for one stage.
3) A) Is fH* for two stages greater or smaller than fH for a single stage? Explain.B) Repeat fL* versus fL.
4) A) Given an approximate expression relating fH* and 3-dB frequencies of n non-identical stages?B) For two identical stages what is fH* / fH? Repeat for three stages.
5) A) Prove that the response of a two stage (identical) amplifier to a unit step is V0 = A0
2 {1 – (1+x)e-x}, where A0 is mid band gain and x = t / R2C2.B) For t<< R2C2 ; show that output varies quadratically with time.
6) A) Draw the circuit of a two-stage RC coupled CE amplifier.B) Draw the small signal equivalent circuit for one stageC) Draw the equivalent circuit valid for middle frequency range and derive the
expression for mid-band current gain AIM and voltage gain AVM.
7) A) Draw the circuit of two-stage RC coupled CS amplifier.B) Describe its operation.
8) A) For a cascade of n transistor CE stages, how many poles will the voltagetransfer function have? Explain.
B) Repeat for the no. of zeros.
9) A) What are multi stage amplifiers? B) Derive the equation for the over all voltage gain of a multi stage amplifier
in terms of the individual voltage gains.
10) Three identical cascaded stages have an overall upper – 3dB frequency of 20 KHZ and a lower 3-dB frequency of 20HZ. What are fL and fH of each stage? Assuming non-interacting stages?
11) If two cascaded single – pole stages have unequal band passes, show that the combined bandwidth is essentially that of smaller. Assume non-interacting stages.
12) Discuss briefly the choice of transistor configuration in a cascade amplifier.13) The following is a two-state amplifier circuit in CE-CC configuration. The
transistor parameter at the corresponding quiescent points are hie = 2k, hfe = 50 hre = 6 x 10-4 hoe = 25A/V; hic = 2k, hfc = -51hrc = 1; hoc = 25A/V. Find the input and output impedance and individual as well as over all voltage and current gain.
14) Determine the overall voltage gain of the cascade amplifier shown in the following figure with RB1 = 7.5K, RB2 = 6.8K, RB3 = 3.3K, RE = 1.3K and RC = 2.2K. For the two transistors 1 = 2 = 120 and supply voltage VCC
= 18V.
VS
+ VCC
VO
RC1
5K
Q1
5KRe2
1K
-VEE
15) The parameters of the transistors in the circuit shown are hfe = 50, hie = 1.1K, hre = hoe =0. Find (a) the midband gain, (b) the value of Cb necessary to give a lower 3-dB frequency of 20Hz. Assume that Cz represents a short circuit at this frequency. (c) Find the value of Cb necessary to ensure less than 10 percent for a 100-Hz square-wave input.
16) A two-stage FET RC-coupled amplifier has the following parameters; gm = 10 mA/v, rd = 5.5K,Rd = 10K and Ro = 0.5M for each stage. Assume C8 in the figure to be arbitrarily large.(a) What must be the value of Cb in order that the frequency
characteristic of each stage be flat within 1dB down to 10Hz?(b) Repeat the part a if the overall gain of both stages is to be down
1dB at 10Hz.(c) What is the overall midband voltage gain
17) A three-stage RC-coupled amplifier uses field-effect transistors in the above figure, with the following parameters; gm = 2.6mA/V, rd = 7.7K, Rd = 10 K, Ro = 0.1M, Cb = 0.005A, and C8 = . Evaluate (a) the overall midband voltage gain in decibels, (b) fL of each individual stage, (c) the over all lower 3-dB frequency.
18) Describe a transformer coupled Amplifier.
19) The R.C. coupled Amplifier has mid-frequency gain (AV)m = 100. The value of lower and upper cut-off frequencies are f1 = 20HZ and f2 = 50KHZ. Find the frequencies at which gain is reduced to 80.
20) A two stage CE RC coupled amplifier uses transistors of the type BC149B of which h parameters are hie – 4.5K and hfe = 330. If the load resistance RL = 5.5K, find the required value of coupling capacitor C so that the lower cut-off frequency is 60HZ.
UNIT – II
MULTI STAGE AMPLIFIERS
QUIZ TYPE QUESTIONS:
1) Amplifiers are coupled to __________.
2) R.C. coupling is used for __________ amplification
3) Transformer coupling is mostly used for _________ amplification
4) R-C coupled amplifier has a very ______ frequency response curve.
5) Direct coupling is used for amplifying _______________________.
6) In an amplifier, the coupling capacitors are used a) To match the impedancesb) To control the outputc) To limit the band widthd) To prevent d.c., mixing with input or output
7) Multi stage amplifiers are used in order to achieve greater.a) Voltage amplificationb) Frequency responsec) Power gaind) All of the above.
8) The main component responsible for the full of gain of an R-C coupled amplifier in low frequency range ina) Coupling capacitorb) Resistor Re
c) Biasing systemd) The device (transistor)
9) A two stage amplifier with negative feed back a) Can become unstable for larger values of b) Becomes unstable at very high and very low frequencies it A is very largec) Becomes unstable when the pole frequency becomes couplingd) Is always stable
10) In transformer coupled multi stage CE Amplifier, on what factors do the low frequency and high frequency response depends.
11) If four cascaded stages must provide an over all band width, fw, of 1MHZ, what must be the minimum Band width of each, assuming all stages have the same f2.
UNIT – III HIGH FREQUENCY TRANSISTOR CIRCUITS
ESSAY TYPE:
1. Explain hybrid- model of bjt?
2. derive relation hybrid- conductance and h-parameters of transistor?
3. Describe high freq model of bjt?
4. What are and cut-off frequencies?
5. what is importance of “fT”
6. give the expanded hybrid- model taking early effect into account?
7. what are the limitations of hybrid - model?
8. Discuss the effect of early-effect on hybrid- model?
9. write a short notes on T-model of BJT?
10. Sketch and discuss High freq response of BJT?
UNIT – III HIGH FREQUENCY TRANSISTOR CIRCUITS
QUIZ TYPE QUESTIONS:
1. What are and cut-off frequencies?
2. which component of rc coupled amplifier is mainly responsible for fall of gain in high freq range?
3. What is “rise time”?
4. How do you measure an amplifiers rise time?
5. Distinguish between “fT” and “f ”?
6. Mention typical magnitudes for elements of hybrid- model at room temp and for Ic=1.3ma.
7. Write expression for Ce in terms of ‘fT’ and ‘gm’?
8. Express hybrid- model elements in terms of h-parameters at low freq for a given Ic?
9. Mention the freq range in which hybrid model is valid?
10. An npn silicon Transistor has f =1Mhz and ce low freq o of 200 determine its unity gain freq fT,f?
11. what is voltage gain of amplifier at fT?
UNIT – IV POWER AMPLIFIERS
Essay Type:
1. What is an audio power amplifier? Explain the difference between voltage and power amplifier.
2. Explain briefly what is meant by each of the following:i). Class-A amplifierii). Class-B amplifieriii).Class-AB amplifieriv). Class-c amplifier andv). Class-D amplifiervi). Efficiency of a power amplifier
3. What is the condition for thermal stability in power amplifier?4. The complementary symmetry class-B power amplifier shown in the figure
has sinusoidal input. Calculatei). Maximum a.c. power out putii). Power dissipation in each transistor
5. Define and explain the following term as applied to power amplifier.i) Collector efficiencyii) Power dissipation capability andiii) Over all gain.
6. Show that maximum collector efficiency of a class `A’ transformer coupled amplified in 50%.
7. An audio power amplifier operates in class-B mode and delivers 16 Volts peak signal into a 16 ohms speaker when the DC supply to the amplifier is 30V. Calculate the efficiency of the amplifier. If the output signal across the speaker is 20 Volts peak to peak. Calculate the actual power delivered by the amplifier.
+
-
5
C
VOVi
+
-
+25V
8. A class-A power amplifier is designed to deliver power to a 100 ohm through a 10:1 transformer. Find the maximum power output, if the zero signal collector current as 100mA.
9. A transistors has a junction to case thermal resistance of 1K/W when its VCE=20V and IC=1A. The room temperature is 250c. Calculate the thermal resistance of the heat sink to keep the junction temperature from exceeding 850c.
10. What is total harmonic distortion? In which class of amplifiers is this distortion (THD) less? How?
11. Describe a transistor class `A’ power amplifier with resistance load. How power is distributed in it.
12. Calculate the expression for collector efficiency and over all efficiency of class A, CE amplifier with resistive load.
13. Describe a transistor class `A’ power amplifier unit output transformed as load. Describe its working and find an expression for its efficiency.
14. Calculate over all efficiency of class B power amplifier.
15. Draw the circuit diagram of a push-pull amplifier. Explain its operation. Discuss advantages and disadvantages.
16. Explain the difference between a voltage and a power amplifier. Show that the maximum collector efficiency of class `A’ push pull amplifier is 50%.
17. Draw the circuit diagram of a class `B’ push pull amplifier and explain its operation. Derive an expression for its maximum conversion efficiency.
18. Explain:a) Why does collector efficiency play important part in power
amplifier?b) Why does the output stage employ push-pull arrangement?
19. A 16 speaker is, driven by a transformer-coupled class `A’ amplifier through a 15: 1 transformer. The circuit delivers 2 watts to load VCC = 36A. Calculate.a) AC power across transformer primary b) R.M.S. value of load voltage.c) R.M.S. value of primary voltage.d) R.M.S. value of load and primary current
UNIT – IV POWER AMPLIFIERS
Quiz Type:
1. A power amplifier operated in class – A mode provides ______________ conversion efficiency and ________________ distortion.
2. A class – B power amplifier gives rise to _____________ distortion, which is absent in other classes of amplifiers.
3. The equation “VCQICQ=Constant” is plotted on the collector characteristics. The path of the curve appears in the form of a a) circle b) parabola c) ellipse d)hyperbola
4. If the input power to a push-pull class `B’ amplifier is 10 Watts, what is the maximum output power from it?
5. What is meant by Complementary symmetry in push-pull amplifiers?
6. What is the best feature of class – C amplifiers?
7. In which of the following the out put current flows throughout the input cycle time?a) Class – A b) Class – B c) Class – C d) Class – AB
8. What is meant by Heat sink?
9. What is the system international unit of thermal conductivity? Thermal resistance.
10. The peak-to-peak sinusoidal voltage across a loud speaker having 15 ohms impedance is found to be 30 volts. What is the power from the speaker?
11. What happens to the Q-point as the input signal to a power amplifier is increased? Assume Class-A operation.
12. What is the main difference between the DC coupled and the transformer coupled Class – A power amplifiers?
13. What is the function of the bypass capacitor and the blocking capacitor in power amplifier?
14. What is meant by reflected impedance in the case of transformer coupled power amplifier?
15. What is a tank circuit used as a load impedance in Class – C amplifiers?
16. Name two important differences between a small signal transistor and a power transistor?
17. The AC power output of a Transformer coupled class – A power amplifier at its highest possible efficiency is 0.5 watts. What is the power dissipated in the transistor?
18. The type of transformer used in power amplifier to couple the output signal to the load impedance is:a) Step-up b) 1:1 isolation c) Step-down d) Auto
19. A class B push-pull amplifier has the main advantage of being free from a) Unwanted noise (b) Circuit imbalancec) Even-odder harmonic distortion (d) Amplitude modulation.
20. The main purpose of using transformer coupling in a class A amplifier is to make it morea) Efficient (b) less costly (c) less bulky (d) distortion free
UNIT - V
TUNED AMPLIFIERS-I
ESSAY:
1) What do you mean by a tuned amplifier? Explain a single tuned inductively coupled transistor amplifier.
2) What are various types of tuned amplifier? Describe a double tuned amplifier.
3) Distinguish between single tuned, double tuned and stages tuned amplifier. Discuss the effect of “Q” on Bandwidth of a tuned amplifier.
4) Derive the equivalent circuit of capacitance coupled single tuned amplifier and derive the equation of voltage gain.
5) Derive the equation for the 3dB Bandwidth of double tuned amplifier
6) Discuss the effect of cascading tuned amplifier on Bandwidth.
UNIT – V
TUNED AMPLIFIERS-I
QUIZ:
1) Write down the relationship between Bandwidth and effective Q of a tuned amplifier.
2) Point out different methods of coupling the load to a tuned amplifier.
3) What is meant by neutralization?
4) Why tuned amplifier cannot be used at low frequency?
5) Define quality factor.
6) Define gain bandwidth product of a tuned amplifier?
7) What factors govern the selectivity of a single tuned amplifier?
8) Mention the draw back of a single tuned amplifier.
9) Mention the bandwidth of a double tuned amplifier.
10) A parallel tuned circuit offers _________ impedance at resonance.
11) Tuned voltage amplifiers are not used __________.a) Public-address systemb) Radio receiverc) In television receiver.
UNIT - VI
TUNED AMPLIFIERS-II
ESSAY TYPE:
1. What is a stagger-tuned amplifier? Explain its working.
2. With a neat diagram show how to cascade tuned amplifiers and determine gain and band width.
3. Discuss the unilaterisation and mismatch technique of stabilization in tuned amplifiers.
4. A) Explain in brief the function of tank circuit in tuned voltage amplifier.B) Explain the effect of changing Q of coil used in tank circuit, on its
Bandwidth.
5. Draw the circuit diagram of class B tuned power amplifier and explain its working.
6. Repeat the above for class C.
UNIT – VI
TUNED AMPLIFIERS-II
QUIZ:
1. What is synchronously tuned amplifier?
2. What is stagger-tuned amplifier?
3. Mention the application of tuned amplifier?
4. Differentiate between single tuned and staggered tuned amplifier.
5. What are the characteristics of ideal tuned amplifier?
6. List the performance measures of a tuned amplifier.
7. How stagger tuning is achieved in tuned amplifier?
8. What is effective of `Q’ stability?
9. Distinguish between neutralization and unilateralization.
10. Why impedance matching is needed for the tuned amplifiers?
11. A parallel tuned circuit offers _________ impedance at resonance.
12. Tuned voltage amplifiers are not used __________.a. Public-address systemb. Radio receiverc. In television receiver.
UNIT – VII
VOLTAGE REGULATORS
ESSAY TYPE QUESTIONS:
1) Draw the circuit diagram of a half wave voltage doubler and explain its operation.
2) Repeat question No.1 for a full – wave voltage doubler.
3) Draw the circuit of a voltage Tripler and quadrupler and explain its operation.
4) A) Define the terms (i) Voltage regulation (ii) Line regulation.B) A 50V power supply has line regulation 0.2% / V. How large would the
75V input voltage to the supply have to become in order for the output voltage to rise to 52V?
5) Explain the operation of BJT series voltage regulator and also derive an expression for its stability factor.
6) Briefly explain the operation and stability factor of zener voltage regulator.
7) Draw the schematic diagram of a series voltage regulator that employs one transistor and one zener diode and that can be operated from an unregulated negative voltage to produce a regulated negative voltage.
8) Describe the operation of BJT shunt voltage regulator and also derive the necessary relation of its stability factor.
9) When the regulated output voltage in following figure is 18V, Vin supplies a total current of 0.5A. If RL = 100, VZ = 6V, R1 = 200 and the collector current in Q2 is negligible, find the power dissipated by Q1.
Q2
Q1
Vin
VO
RS
RL
R1
UNIT – VII
VOLTAGE REGULATORS
QUIZ TYPE QUESTIONS:
1) What is the function of a voltage regulator?
2) Give the important parts of series regulated power supply using discrete components.
3) What is voltage reference? Why it is needed?
4) What is the function of series pass transistor?
5) Give two advantages of series voltage regulator.
6) Draw the circuit of shunt regulator.
7) What are advantages of adjustable IC regulators against fixed IC regulators?
UNIT – VIII
SWITCHING AND IC VOLTAGE REGULATORS
ESSAY TYPE QUESTIONS:
1) With a neat sketch explain the principle of operation of switched mode power supply.
2) In the following figure, Vin = 20V, R = 200 and VZ = 12V. If VBE = 0.65V, find (a) V0 (b) VCE of the pass transistor and (c) current in the 200 resistor.
3) Explain the operation of IC voltage regulator units neat sketch.
4) List and explain the characteristics of three terminal IC regulators.
5) What is the principle of switch mode power supplier? Discuss its advantages and disadvantages.
6) Using 7805, design a current source to deliver 0.2A current to a 22, 10W load.
7) Design an adjustable regulator from 7810, regulator to get an output voltage of 15V.
Vin
R
+
-
Vt
VBE
VO
RL
IL
+
UNIT – VIII
SWITCHING AND IC VOLTAGE REGULATORS
QUIZ TYPE QUESTIONS:
1) Show the standard representation of IC voltage regulator.
2) What are the limitations of three terminal regulators?
3) What voltage options are available in 78XX and 79XX voltage regulators?
4) What is main advantage of SMPS?
5) How do you classify IC regulators?
6) What are advantages of IC regulator?
7) What is difference between 78XX and 79XX?
8) What is positive IC regulator? Explain with one example.
9) What are advantages of adjustable IC regulators against fixed IC regulators?
