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Eca Lab Manual

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Draft copy for adoption: LABORATORY MANUAL ELECTRONIC CIRCUITS ANALYSIS B.Tech II nd yr ECE Prepared at siddarth institute of engineering and technology Design and review by. A.KARUNAKAR M.Tech., Assistant professor. s.HARI PRASAD B.Tech, Assistant professor.
Transcript
Page 1: Eca Lab Manual

Draft copy for adoption:

LABORATORY MANUAL

ELECTRONIC CIRCUITS ANALYSISB.Tech II nd yr ECE

Prepared at siddarth institute of engineering and technology

Design and review by.

A.KARUNAKAR M.Tech.,

Assistant professor. s.HARI PRASAD B.Tech,

Assistant professor.

Department of E.C.E

Page 2: Eca Lab Manual

LIST OF EXPERIMENTS

1.Common emitter amplifier

2. Common source amplifier

3.A two stage RC coupled amplifier

4.Current shunt and voltage series feedback amplifier

5.Cascade amplifier

6.Wien bridge oscillator using transistors

7.RC phase shift oscillator using transistors

8.Class A power amplifier

9.Class B complimentary symmetry amplifier

10.High frequency common base (BJT)/common gate (JFET) amplifier

Page 3: Eca Lab Manual

ELECTRONIC CIRCUITS LAB

EXP . NO. 1. TWO STAGE RC-COUPLED AMPLIFIER

1. AIM:

To Design and study the response of a two stage RC-coupled amplifier and calculation of gain and band width.

2. EQUIPMENTS AND COMPONENTS:

i.APPARATUS1. CRO (Dual channel)DC-20 MHz 1 No2. Bread Board - ! No. .3. Regulated power supply- 0-30v 1 A, 1 No.4. DMM 3 ½ Digit LCD hand held 1No5. Function generator ! MhZ 1 No.

ii.COMPONENTS:

1. 62kΩ Resistor – 2 No.2. 4.7kΩ Resistor – 3 No.3. 1.5Ω Resistor – 2 No4. 33kΩ Resistor – 2 No5. 1kΩ Resistor – 2 No6. 10 μ F/ 16 V Electrolytic Capacitor – 3 No.7. 0.1 μF/16 V Electrolytic Capacitor – 2 No8. Transistors – BC107 – 2 No.

All resistors are carbon / metal film ¼ W 5% unless otherwise specified.

3. THEORY:

As the gain provided by a single stage amplifier is usually not sufficient to drive the load, so to achieve extra gain multi-stage amplifier are used. In multi-stage amplifiers output of one-stage is coupled to the input of the next stage. The coupling of one stage to another is done with the help of some coupling devices. If it is coupled by RC then the amplifier is called RC-coupled amplifier.

Frequency response of an amplifier is defined as the variation of gain with respective frequency. The gain of the amplifier increases as the frequency increases from

Page 4: Eca Lab Manual

zero till it becomes maximum at lower cut-off frequency and remains constant till higher cut-off frequency and then it falls again as the frequency increases.

At low frequencies the reactance of coupling capacitor CC is quite high and hence very small part of signal will pass through from one stage to the next stage.

At high frequencies the reactance of inter electrode capacitance is very small and behaves as a short circuit. This increases the loading effect on next stage and service to reduce the voltage gain due to these reasons the voltage gain drops at high frequencies.

At mid frequencies the effect of coupling capacitors is negligible and acts like short circuit, where as inter electrode capacitors acts like open circuit. So, the circuit becomes resistive at mid frequencies and the voltage gain remains constant during this range.

4. CIRCUIT DIAGRAM:

62

.0k

33

.0k

4.7

k

1.5

k

62

.0k

4.7

k

33

.0k

1.5

k

4.7k 1.0k

100.0n

10

.0u

10

.0u

100.0n

10.0u

T1 !NPN T2 !NPN

Vin

Vcc 12.0

1.0

k V+Vout

6.63v 6.63v

245mv245mv842mv 842mv

Page 5: Eca Lab Manual

ALTERNATE CIRCUIT :

V+Vout

2.2

k

Vcc 12.0

Vin

T1 !NPN

10.0u

10.0u

10

0.0

u

10

0.0

u

10.0u

10.0k

1.0

k

2.2

k

10

.0k

47

.0k

1.0

k

10

.0k

2.2

k

47

.0k

T2 !NPN

10.0k

10

.0k

10

.0u 8.94v8.94v

2.05v 2.05v 1.4v1.4v

5. PROCEDURE:

i.. Connect the circuit on bread board as shown in the circuit diagram.

ii. Measure base ,emitter and collector D.C voltages of both stages and compare against estimated values.

Estimated voltages Observed voltagesVb1 ,Vc1, Ve1Vb2, Vc2, Ve2

iii. By keeping the amplitude of the input signal constant, vary the frequency from zero to 1 MHz.

iv. Note down the amplitude of the output signal for corresponding values of input frequencies.

v. Calculate the voltage gain in decibels.

vi. Plot in semi-log graph between gain vs frequency and calculate the band width.

Page 6: Eca Lab Manual

6. OBSERVATIONS:

S.NO FREQUENCY VOUT GAIN= VOUT /VIN GAIN in dB

7. CALCULATIONS:

i. Determine lower cut-off frequency and upper cut-off frequency from the graph.

ii. Calculate Band width.

8. GRAPH:

Page 7: Eca Lab Manual

9. RESULT:

i. Lower cut-off frequency =

ii. Upper cut-off frequency =

iii. Band width =

10. INFERENCES:

This circuit is useful for amplification by providing higher gain in the range __________

11. PRECAUTIONS:

i. Test Transistors before assembling the circuits

ii. Mark polarities of electrolytic capacitors and connect.

iii. Apply voltage from the power supply and proceed further only after obtaining expected DC voltages at base emitter collector of the transistors.

Page 8: Eca Lab Manual

iv. If above are correct you can apply signal from function generator and monitor the output on CRO and adjust signal amplitude such that output seen in CRO is free from rounding and clipping of the signals.

v. If you face any problem with signal on CRO due to wrong settings of the controls check up connections to CRO

vi Resistors should be connected properly with out interchanging the values.

vii .Check the continuity of the connecting wires.

12. APPLICATIONS:

1. Audio amplifiers

2. Radio Transmitters and Receivers.

13. EXTENSIONS:

In general multi-stage amplifiers are used to provide high overall gain for the applied input signal. In this experiment, we verified this with two stages coupled with resistors and capacitors. We can extend the circuit diagram with one or more stages cascading with the given two stages RC coupled amplifier. We can extend low frequency range by increasing coupling and bypass capacitors. By employing negative feedback, we can ensure constant gain against device parameters.

This experiment is carried on with two stages of amplifiers operating with low current. RC coupling can be made between amplifiers with any type of biasing methods instead of voltage divider bias as shown. An alternate circuit is shown to enlarge this scope of study of RC amplifier (1) study effect of individual LF cutoff on the overall cutoff.

(2) Measure input impedance of amplifier

(3) Study effect on overall LF cutoff due to individual RC couplings at the input and emitter by capacitors.

(4) Apply small square wave and measure rise times on individual stages and verify formula on rise times.

(5) Since high frequency cutoff is determined by output capacitance of transistors 1:1 probes used on CRO can lower HF cutoff. In order to avoid this effect intentionally a large capacitors of 0.1 microfarad or the like is connected such that high frequency cutoff falls well below 1 megahertz.

Page 9: Eca Lab Manual

14. TROUBLE SHOOTING:

S.NO FAULT DIAGNOSIS

1. If there is no output Check Vcc and all DC voltages. Check function generator.

Check CRO connections.2. If the output is distorted Check Vcc and all DC voltages

Check amplitude of input signal.3. If DC voltages differ very much Check entire circuit for connections,

resistance values and placementsCheck Transistors.

15. Special tip to measure Bandwidth without graph. graph. Note amplitude at mid band and vary frequency towards low frequency till amplitude falls by 30% .Let this be f1. Repeat this step towards high frequency end until amplitude falls by 30%.Let this be f2. Band width is f2-f1.

15. QUESTIONS:

i. What are the advantages and disadvantages of multi-stage amplifiers?

ii. Why gain falls at HF and LF?

iii. Why the gain remains constant at MF?

iv. Explain the function of emitter bypass capacitor, Ce?

v. How the band width will effect as more number of stages are cascaded?

vi. Define frequency response?

vii. Give the formula for effective lower cut-off frequency, when N-number of stages are cascaded.

viii. Explain the effect of coupling capacitors and inter-electrode capacitances on overall gain.

ix. By how many times effective upper cut-off frequency will be reduced, if three identical stages are cascaded?

x. Mention the applications of two-stage RC-coupled amplifiers.

Page 10: Eca Lab Manual

EXP.NO.2 SERIES VOLTAGE REGULATOR

1. AIM:

To design a transistorized series voltage regulator and study the regulation action for

i. Different values of input voltages

ii Different values of load resistors and also to find percentage regulation.

2. EQUIPMENTS AND COMPONENTS:

i.APPARATUS

1. CRO (Dual channel)DC-20 MHz 1 No2. Bread Board - ! No. .3. Regulated power supply- 0-30v 1 A, 1 No.4. DMM 3 ½ Digit LCD hand held 1No

ii. COMPONENTS:

1. 1kΩ Resistor – 1 No.2. 560Ω Resistor – 1 No.3. 1k , 2k , 4.7k, 10k (load resistors ) – 1 No each.

4. Zener diode – 1 No.5. Transistor – SL100 – 1 No.

All resistors are carbon / metal film ¼ W 5% unless otherwise specified.

3. THEORY:

Voltage regulator is a device designed to maintain the output voltage as nearly constant as possible. It monitors the output voltage and generates feed back that automatically increases are decreases the supply voltage to compensate for any changes in output voltage that might occur because of change in load are changes in load voltages.

In transistorized series voltage regulator the control element is a transistor which is in series with load. must be operated in reverse break down region, where it provides constant voltage irrespective of changes in applied voltages.The output voltage of the series voltage regulator is Vo = Vz – Vbe.

Page 11: Eca Lab Manual

Since, Vz is constant, any change in Vo must cause a change in Vbe in order to maintain the above equation. So, when Vo decreases Vbe increases, which causes the transistor to conduct more and to produce more load current, this increase in load causes an increase in Vo and makes Vo as constant. Similarly, the regulation action happens when Vo increases also.

4. CIRCUIT DIAGRAM:

560.0

1.0

k

Z1 B

ZD

27-C

5V

1

T1 !NPN 1

.0k

V+

Vout

Vin 1.010 30v

5. PROCEDURE:

i. Connect the circuit as shown in the circuit diagram.

ii. Apply the input voltage from power supply.

iii. Measure base ,emitter and collector D.C voltages and compare against estimated values.

Estimated voltages Observed voltagesVb1 ,Vc1, Ve1Vz

iv. For a specific value of load resistor, vary the input voltage from 10 to a maximum of 20 volts and not the values of output voltage.

v. Change the load resistor and repeat steps 2 and 3.

vi. Remove the load resistor and note down the voltage at no load.

Page 12: Eca Lab Manual

vii. Find percentage regulation.

Percentage regulation =

viii. Plot the graph for load regulation and line regulation.

6. OBSERVATIONS:

S.no Vin Output voltageRL= RL= RL=

7. CALCULATIONS:

Percentage load regulation = =

Percentage Line Regulation = (change in output ) / (change in input) X 100

Page 13: Eca Lab Manual

8. GRAPH:

9. RESULT:

For RL = ----------------, Regulating range is____________

For RL = ----------------, Regulating range is____________

For RL = ----------------, Regulating range is____________

10. INFERENCES:

This Series Regulator is useful for the input voltage range ______________

Page 14: Eca Lab Manual

11. PRECAUTIONS:

i. Test Transistors, zener diode before assembling in the circuits.

ii. Apply voltage from 15 V and ensure the DC voltages as shown the circuit are obtained. Check circuit connections and components if expected voltages are not obtained.

iii. Check resistor values properly otherwise power supply may be over loaded due to small values.

iv. If Zener is reversed no damage will occur but output voltage will fall down to 0 V.

v. Don't short the output as this would result in large current through the series transistor which will lead to burning of the same due to overheat.

12. APPLICATIONS:

1. Low current applications.

2. Fixed voltage applications

3. Extention of zener regulator for higher currents.

13. EXTENSIONS:

The main function of voltage regulator is to regulate the changes in output voltage for the changes occur either in input voltage variations or output load variations. In this experiment we have verified for one particular value of output voltage. We can obtain voltage regulation at higher voltages with the help of more number of Zener diode operating in break down region, must be connected in series. For example, to obtain voltage regulation at 8.2 volts, we can use the same circuit with two Zener diodes of values 3.1 volts and 5.1 volts respectively.By employing a series regulator with error amplifier , variable regulated voltage can be obtained from circuit given below.The experiment is conducted is of simplest type to demonstrate use of zener and series pass transistor without any unregulated voltage power supply. In real application regulated power supply used at the input of this experiment will be replaced by a full wave or bridge rectifier with capacitor input filter suitable to the load and ripple voltages expected. The series transistor would be a power transistor with high current capacity and would be mounted to heat sink. Ripple can be simulated by change in input and the corresponding change in output at a constant load current.

One can obtain different fixed voltages by suitably changing the zener diode. One can obtain higher current ratings by employing suitable series power transistor and heat sinks.

Page 15: Eca Lab Manual

14. TROUBLE SHOOTING:

S.NO FAULT DIAGNOSIS

1. If there is no output Check Vi and all DC voltages.

Check CRO connections..2. If DC voltages differ very much Check entire circuit for connections,

resistance values and placementsCheck Transistors.

15. QUESTIONS:

i. Define voltage regulator.

ii. Give the advantages of series voltage regulator. .

iii.. Explain the feed back mechanism in series voltage regulator.

iv. In series voltage regulator which is control element and explain its function.

v. Define load and line regulation. What is ideal value ?.

vi. Which element determines output ripple ?

vii. What determines maximum load current allowed in this circuit ?

viii. Mention the applications of series voltage regulator.

ix. Define no load voltage and full load voltage.

x. Explain the term percentage regulation.

Page 16: Eca Lab Manual

EXP .NO. 3 SHUNT VOLTAGE REGULATOR

1. AIM:

To design a transistorized shunt voltage regulator and observing the regulation action for

i. Different values of input voltages

ii Different values of load resistors and also to find percentage regulation.

2. EQUIPMENTS AND COMPONENTS:

i.APPARATUS

1. CRO (Dual channel)DC-20 MHz 1 No2. Bread Board - ! No. .3. Regulated power supply- 0-30v 1 A, 1 No.4. DMM 3 ½ Digit LCD hand held 1No

ii.COMPONENTS:

1. 1kΩ Resistor – 1 No.2. 560Ω Resistor – 1 No.3. 1k , 2k , 4.7k, 10k (load resistors ) – 1 No each.

4. Zener diode – IN 4007 - 1No.5. Transistor – SL100 – 2No.

All resistors are carbon / metal film ¼ W 5% unless otherwise specified.

3. THEORY:

A voltage regulator is a device or a combination of devices, design to maintain the output voltage of a power supply as nearly constant as possible even if there are changes in load or in input voltage. In shunt voltage regulator transistor Q1 acts as control element, which is in shunt with load voltage.

The output voltage is given as

Vo = Vz + VR1 = Vz + Vbe1 + Vbe2

The regulation action of the circuit is explained below :Since Vz is constant, any changes in output voltage reflects a propositional

change in R1. If the output voltage decreases, voltage across R1 decreases which in turn decreases the base voltage of Q2. As a result the base current of Q1 decreases which

Page 17: Eca Lab Manual

allows the load voltage to rise and makes it constant the same regulation action follows even if the output voltage increases.

4. CIRCUIT DIAGRAM:

+

- -

+

R L

D 1 V z

R S

5 6 0 E

Q 1

S L 1 0 0

R 11 k

Q 2

S L 1 0 0

Unreg ulated PowerS upply

+

+

+

-

-

-Vbe1

Vbe2Vo

ALTERNATE CIRCUIT :

T1 !NPN

1N

378

5 1

.0k

180.0

Vdc

20.

0

1.0

kVz = 6.3v RL = 1k,2k , 4.7k ,10k

Page 18: Eca Lab Manual

5. PROCEDURE:

i. Connect the circuit as shown in the circuit diagram.

ii. Apply the input voltage from power supply.

iii. Measure base ,emitter and collector D.C voltages and compare against estimated values.

Estimated voltages Observed voltages

Vb1 ,Vc1, Ve1Vb2 ,Vc2, Ve2Vz

iv. For a specific value of load resistor, vary the input voltage from zero to a maximum of 20 volts and note the values of output voltage.

iv. Change the load resistor and repeat steps 2 and 3.

v. Remove the load resistor and note down the voltage at no load.

vi. Find percentage regulation.

Percentage regulation =

vii. Plot the graph for load regulation and line regulation.

Page 19: Eca Lab Manual

6. OBSERVATIONS:

VOLTAGE AT NO-LOAD =

S.no Vin Output voltageRL= RL= RL=

7. CALCULATIONS:

Percentage regulation =

8. GRAPH:

Page 20: Eca Lab Manual

9. RESULT:

For RL = ----------------, Regulating range is____________

For RL = ----------------, Regulating range is____________

For RL = ----------------, Regulating range is____________

10. INFERENCES:

This Shunt Regulator is useful for the input voltage range ______________

11. PRECAUTIONS:

i. Proceed on the experiment only after obtaining expected DC voltages do not apply more than 20 V without connecting load on the output as this would result in maximum current in shunt transistors.

ii. Shorting the output will result in overheating series resistors which may burn at high voltage.

iii. Reversing the zener may not damage the circuit but result in output voltage to drop 2 V or less.

12. APPLICATIONS:

1. Low current applications. 2. Fixed voltage applications

13. EXTENSIONS:

The main function of voltage regulator is to regulate the changes in output voltage for the changes occur either in input voltage variations or output load variations. In this experiment we have verified for one particular value of output voltage. We can obtain voltage regulation at higher voltages with the help of more number of Zener diode operating in break down region, must be connected in series. For example, to obtain voltage regulation at 8.2 volts, we can use the same circuit with two Zener diodes of values 3.1 volts and 5.1 volts respectively.The experiment is conducted is of simplest type to demonstrate use of zener and series pass transistor without any unregulated voltage power supply. In real application regulated power

Page 21: Eca Lab Manual

supply used at the input of this experiment will be replaced by a full wave or bridge rectifier with capacitor input filter suitable to the load and repule voltages expected. The series transistor would be a power transistor with high current capacity and would be mounted to heat sink.Ripple can be simulated by change in input and the corresponding change in output at a constant load current.

One can obtain different fixed voltages by suitably changing the zener diode. One can obtain higher current ratings by employing suitable series power transistor and heat sinks.

14. TROUBLE SHOOTING:S.NO FAULT DIAGNOSIS

1. If there is no output Check Vi and all DC voltages.

Check CRO connections..2. If DC voltages differ very much Check entire circuit for connections,

resistance values and placementsCheck Transistors.

15. QUESTIONS:

i. Mention the differences between shunt and series voltage regulators.

ii. What is the function of Q1 and Q2 in the shunt regulator .circuit ?

iii. Define the line regulation. And load regulation.

iv. What is current through zener in this circuit ?

v.. When is dissipation maximum in this circuit ?

vi. In the circuit of shunt voltage regulator which element is considered control element and explain its function.

vii. Can you do the experiment without Q2 ?.

viii. How can you increase current range of regulator ?

ix. . If output is 1.4 v for input of 20v what was the wrongly connected ?

x. Mention the applications of shunt voltage regulator.EXP. NO. 4 SERIES FED CLASS-A POWER AMPLIFIER

Page 22: Eca Lab Manual

1. AIM:

To design a series fed class-A power amplifier in order to achieve max out put ac power and efficiency.

2. EQUIPMENTS AND COMPONENTS:

i.APPARATUS

1. CRO (Dual channel)DC-20 MHz 1 No2. Bread Board - ! No. .3. Regulated power supply- 0-30v 1 A, 1 No.4. DMM 3 ½ Digit LCD hand held 1No5. Function generator ! MhZ 1 No.

ii. COMPONENTS:

1. 20kΩ Resistor – 1 No.2. 1kΩ Resistor – 2 No.3. 0.1 μF/16 V Electrolytic Capacitor – 2 No.4. Transistor – SL100 – 1No.

All resistors are carbon / metal film ¼ W 5% unless otherwise specified.

3. THEORY:

The above circuit is called as “series fed” because the load RL is connected in series with transistor output. It is also called as direct coupled amplifier.ICQ = Zero signal collector currentVCEQ = Zero signal collector to emitter voltagePower amplifiers are mainly used to deliver more power to the load. To deliver more power it requires large input signals, so generally power amplifiers are preceded by a series of voltage amplifiers.In class-A power amplifiers, Q-point is located in the middle of DC-load line. So output current flows for complete cycle of input signal. Under zero signal condition, maximum power dissipation occurs across the transistor. As the input signal amplitude increases power dissipation reduces.The maximum theoretical efficiency is 25%.

4.CIRCUIT DIAGRAM:

Page 23: Eca Lab Manual

20

.0k

1.0

k

100.0n

100.0n

T1 !NPN

Vcc 5.0

VinV+

Vout

1.0

k

A+

iL

2.83v

666mv

5. PROCEDURE:

i. Make the connections as per the circuit diagram.

ii. Measure base ,emitter and collector D.C voltages of both stages and compare against estimated values.

Estimated voltages Observed voltages

Vb1 ,Vc1, Ve1i.

iii. Apply the input at input terminals of the circuit from the function generator.

iv. Keep the input signal at constant frequency under mid frequency region and adjust the amplitude such that output voltage undistorted.

v. Calculate the power efficiency and compare it with theoretical efficiency.

6. OBSERVATIONS:

Efficiency is defined as the ratio of AC output power to DC input power

DC input power = Vcc x ICQ

AC output power = VP-P2 / 8RL

Page 24: Eca Lab Manual

7. CALCULATIONS:

Under zero signal condition:

Vcc = IBRB + VBE

IBQ =( Vcc - VBE ) / RB

ICQ = β x IBQ

VCE = Vcc - ICRC

8. GRAPH:

Page 25: Eca Lab Manual

9. RESULT:

The maximum input signal amplitude which produces undistorted output signal is _________

The practical efficiency of the circuit is ________

10. INFERENCES:

The efficiency observed is ___________ against theoretical maximum of 25%,since ___________________

11. PRECUATIONS:

i. It is a necessary to find a suitable RB required for biasing the amplifier collector at the centre of voltage VCC/2 i.e. 6 V. this shall be done by trial and error or using a decade resistance box.

ii. While observing on CRO at collector of the transistor you can verify whether you are getting undistorted peak to peak signal of at least 10 to 11 V

iii. Since AC and DC load lines are different peak to peak signal without connecting capacitor and load on the collector of transistor will be different than the reading with above connected.

12. APPLICATIONS:

This is used for low power linear applications in audio and wideband RF range, where high efficiency is not required.

13. EXTENSIONS:

In series fed class-A power amplifier we have calculated the efficiency i.e. how efficiently DC-power is converted into AC-power depending on the magnitude of input signalOnce we design a power amplifier for a particular efficiency, the circuit will not give that efficiency to all its input signals of different amplitudes. Hence, depending on the input signal we have to choose Vcc to obtain a particular efficiency..By employing Transformer coupling, efficiency can be improved to 50%.The experiment is conducted using low power transistors like BC107, SL100 only to get familiarity in biasing and measurement. Actual power amplifiers operate at 1 watt to 100 watts. This will call

Page 26: Eca Lab Manual

for operating transistors high current and small value resistors of greater than 1/4 to 1 watt which are used in the laboratory. Actual power amplifiers use heat sinks on the transistors.

14. TROUBLE SHOOTING:

S.NO FAULT DIAGNOSIS

1. If there is no output Check Vcc and all DC voltages. Check function generator.

Check CRO connections.2. If the output is distorted Check Vcc and all DC voltages

Check amplitude of input signal.3. If DC voltages differ very much Check entire circuit for connections,

resistance values and placementsCheck Transistors.

15. QUESTIONS:

i. Differentiate between voltage amplifier and power amplifier

ii. Why power amplifiers are considered as large signal amplifier?

iii. When does maximum power dissipation happen in this circuit ?.

iv. What is the maximum theoretical efficiency?

v. Sketch wave form of output current with respective input signal.

vi. What are the different types of class-A power amplifiers available?

vii. What is the theoretical efficiency of the transformer coupled class-A power amplifier?

viii. What is difference in AC, DC load line?.

ix. How do you locate the Q-point ?

x. What are the applications of class-A power amplifier?

EXP. NO. 5 TRANSFORMER COUPLED CLASS-A POWER AMPLIFIER

1.AIM:

Page 27: Eca Lab Manual

To design a transformer coupled class-A power amplifier in order to achieve

maximum out put AC power and efficiency.

2. EQUIPMENTS AND COMPONENTS:

i.APPARATUS

1. CRO (Dual channel)DC-20 MHz 1 No2. Bread Board - ! No. .3. Regulated power supply- 0-30v 1 A, 1 No.4. DMM 3 ½ Digit LCD hand held 1No5. Function generator ! MhZ 1 No.

ii. COMPONENTS :

1. 1kΩ Resistor – 1No.2. 10kΩ Resistor – 1No.3. 100KΩ Resistor – 1No.4. 0.1 μF/16 V Electrolytic Capacitor – 1 No.5. Impedance matching Transformer – 1 No.6. Transistor – SL100 – 1No.

All resistors are carbon / metal film ¼ W 5% unless otherwise specified.

3. THEORY:

In direct coupled class-A power amplifier, power is wasted in load resistance which

leads to decrease in efficiency. To achieve maximum efficiency we can use

transformer to couple the load. Since transformer is used for impudence matching

which facilitates the coupling between lower resistance and source impudence? Due

to AC coupling no DC power is wasted in the load resistor. The load DC resistance of

transformer primary allows any desired level of collector current, while transferring

only variations to RL. By this way the efficiency is increased. The maximum

theoretical efficiency of transformer coupled power amplifier is 50%.

Efficiency is defined as the ratio of AC output power to DC input power

DC input power = Vcc x ICQ

AC output power = VP-P2 / 8RL

Page 28: Eca Lab Manual

4. CIRCUIT DIAGRAM:

T/ F

10

0.0

k

10

.0k

T1 !NPN

1.0

k

100.0n

Vin

Vcc 12.0

V+

VoutA+

Ic

11.49v

626mv

5. PROCEDURE:

i. Make the connections as per the circuit diagram.

ii. Measure base, emitter and collector D.C voltages and compare against

estimated values.

Estimated voltages Observed voltages

Vb1 ,Vc1, Ve1

iii. Apply the input at input terminals of the circuit from the function

generator.

iv. Keep the input signal at constant frequency under mid frequency region

and adjust the amplitude such that output voltage undistorted.

v. Calculate the power efficiency and compare it with theoretical efficiency.

Page 29: Eca Lab Manual

6. OBSERVATIONS:

Efficiency is defined as the ratio of AC output power to DC input power

DC input power = Vcc x ICQ

AC output power = VP-P2 / 8RL

7. CALCULATIONS:

Input DC power = Vcc x ICQ

Output AC power = Vrms x Irms

= VPP2 / 8RL

η =

8. GRAPH:

Page 30: Eca Lab Manual

9. RESULT:

a) The maximum input signal amplitude which produces undistorted output

signal is _________

b) The practical efficiency of the circuit is ________

10. INFERENCES:

The efficiency observed is ___________ against theoretical maximum of 50%,

since ___________________

11. PRECUATIONS:

i. Check the circuit connections before switching on the power supply.

ii. Check the continuity of the connecting wires.

iii. Power handling capacity of resistor should be kept in mind

iv. Control wires must be checked before use

v. Maximum forward current should not exceed value given in data sheet

vi. Resistors should be connected properly with out interchanging the values.

12. APPLICATIONS:

This circuit is used for Impedance matching and DC isolation.

13. EXTENSIONS:

In Transformer coupled class-A power amplifier we have calculated the efficiency i.e. how efficiently DC-power is converted into AC-power depending on the magnitude of input signal.

Once we design a power amplifier for a particular efficiency, the circuit will not give that efficiency to all its input signals of different amplitudes. Hence, depending on the input signal we have to choose Vcc to obtain a particular efficiency.

By employing Transformer coupling, efficiency can be improved to 50%.The experiment is conducted using low power transistors like BC107, SL100 only to get famimiliarity in biasing and measurement. Actual power amplifiers operate at 1 watt to 100 watts. This will call for operating transistors high current and small value resistors of

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greater than 1/4 to 1 watt which are used in the laboratory. Actual power amplifiers use heat sinks on the transsistors.

This concept can be applied for RF and Impedance matching.

14. TROUBLE SHOOTING:

S.NO FAULT DIAGNOSIS

1. If there is no output Check Vcc and all DC voltages. Check function generator.

Check CRO connections.Check transformer.

2. If the output is distorted Check Vcc and all DC voltagesCheck amplitude of input signal.

3. If DC voltages differ very much Check entire circuit for connections, resistance values and placements.Check transistors.

15. QUESTIONS:

i. Differentiate between voltage amplifier and power amplifier

ii. Explain impedance matching provided by transformer?

iii . How do you determine ratings for transistor in this circuit ?.

iv. What is the maximum theoretical efficiency of this amplifier ?

v. What is the range of conduction angle of output current with respective input signal?

vi.. Sketch DC load line and AC load line for this amplifier.

vii. What is collector voltage of transistor with no and maximum signal?

viii. How is DC and AC power measured in this circuit?

ix. For class-A operation how did you locate the Q-point.

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x. What are the applications of class-A power amplifier?

EXP. NO. 6 COMPLEMENTARY-SYMMETRY CLASS-B POWER AMPLIFIER

1. AIM:

To design a complementary-symmetry class-B push-pull power amplifier in order to achieve maximum out put AC power and efficiency.

2. EQUIPMENTS AND COMPONENTS:

i.APPARATUS

1. CRO (Dual channel)DC-20 MHz 1 No2. Bread Board - ! No. .3. Regulated power supply- 0-30v 1 A, 1 No.4. DMM 3 ½ Digit LCD hand held 1No5. Function generator ! MhZ 1 No.

ii.COMPONENTS:

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1. 8Ω ¼ W 5% CF Resistor – 1 No.2. 1 μ F /16 V Electrolytic Capacitor – 1 No.3. Transistors - SL100 – 1 No.4. Transistor – SK 100 – 1 No.

3. THEORY:

Power amplifiers are designed using different circuit configuration with the sole purpose of delivering maximum undistorted output power to load. Push-pull amplifiers operating either in class-B are class-AB are used in high power audio system with high efficiency.In complementary-symmetry class-B power amplifier two types of transistors, NPN and PNP are used. These transistors acts as emitter follower with both emitters connected together.

In class-B power amplifier Q-point is located either in cut-off region or in saturation region. So, that only 180o of the input signal is flowing in the output.

In complementary-symmetry power amplifier, during the positive half cycle of input signal NPN transistor conducts and during the negative half cycle PNP transistor conducts. Since, the two transistors are complement of each other and they are connected symmetrically so, the name complementary symmetry has come

Theoretically efficiency of complementary symmetry power amplifier is 78.5%.

4.CIRCUIT DIAGRAM:

Page 34: Eca Lab Manual

SL100 !NPN

SK100 !PNP

1.0u

Vin

8.0

Vcc 5.0

Vee 5.0

V+

Vout0v

ALTERNATE CIRCUIT :

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22

0.0k

18

.0k

18

.0k

22

0.0k

SL100 !NPN

SK100 !PNP

4.3

4.3

1.0

k

10.0u

10.0u

1.0k

Vin

Vcc 12.0

Vee 12.0

V+

Vout

658mv

-658mv

5. PROCEDURE:

i. Connect the circuit has shown in the circuit diagram.

ii. Measure base ,emitter and collector D.C voltages of both transistors and compare against estimated values.

Estimated voltages Observed voltages

Vb1 ,Vc1, Ve1Vb2, Vc2, Ve2

iii. Apply the input at input terminals of the circuit from the function generator.

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iv. Keep the input signal at constant frequency under mid frequency region and adjust the amplitude such that output voltage undistorted.

v. Calculate the power efficiency and compare it with theoretical efficiency.

6. OBSERVATIONS:

Efficiency is defined as the ratio of AC output power to DC input power

DC input power = Vcc x ICQ

AC output power = VP-P2 / 8RL

7. CALCULATIONS:

Input DC power = Vcc x ICQ

Output AC power = Vrms x Irms

= VPP2 / 8RL

η =

8. GRAPH:

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9. RESULT:

The maximum input signal amplitude which produces undistorted output signal is _________

The practical efficiency of the circuit is ________

10. INFERENCES:

The practical efficiency of the circuit is ________, because of ______________.

11. PRECUATIONS:

i. Use matched pair NPN & PNP transistors for this experiments. Matching can be done by observing hfe of the transistor using DMM.

ii. Transistors recommended are SL100, SK100.

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iii. Transistors heat up at large signal which is necessary to obtain high efficiency.

iv. Do not short the output which will result in burning of the transistors.

v. In the absence of signal DC voltage at emitters is 0 V.

vi. When alternate circuit uses series resistors to compensate any difference in VBE of transistors, ensure obtaining expected DC voltages and proceeds after that.

12. APPLICATIONS:

This circuit is used to drive low impedance without Transformer.

This circuit is used to drive low impedance from DC onwards.

13. EXTENSIONS:

This experiment is designed with low power and low load current only to demonstrate basic principles of maximum efficiency, crossover distortion and driving small loads without transformer. Actual amplifier circuits of above type can be found in audio systems, radio output stages of modern designs. These drive loud speakers directly without any transformers. Present audio systems have power ratings as much as 1000 watts and radios have above 10 watts. These use complementary class B power amplifiers in the basic are modified forms. In view of large power involved special ICs, Transistors with heat sinks are common.

14. TROUBLE SHOOTING:

S.NO FAULT DIAGNOSIS

1. If there is no output Check + and – ve DC voltages. Check function generator.

Check CRO connections.2. If the output is distorted Check Vcc and all DC voltages

Check amplitude of input signal.3. If DC voltages differ very much Check entire circuit for connections,

resistance values and placements Check Transistors.

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15. QUESTIONS:

i. Differentiate between voltage amplifier and power amplifier

ii. Explain impedance matching provided by transformer?

Iii . Under what condition power dissipation is maximum for transistor in this circuit?

iv. What is the maximum theoretical efficiency?

v. Sketch current waveform in each transistor with respective input signal?

vi. How do you test matched transistors required for this circuit with DMM?.

vii. What is the theoretical efficiency of the complementary stage amplifier.

viii. How do you measure DC and AC out put of this amplifier?

ix. Is this amplifier working in class A or B. ?

x. How can you reduce cross over distortion?

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EXP. NO. 7 CLASS-C TUNED POWER AMPLIFIER

1. AIM:

To design class-C tuned power amplifier and to study the class-c tuned power amplifier.

2. EQUIPMENTS AND COMPONENTS:

i.APPARATUS

1. CRO (Dual channel)DC-20 MHz 1 No2. Bread Board - ! No. .3. Regulated power supply- 0-30v 1 A, 1 No.4. DMM 3 ½ Digit LCD hand held 1No5. Function generator ! MhZ 1 No.

ii.COMPONENTS :

1. 4.7kΩ Resistor – 1 No.2. 10kΩ Resistor – 1 No.3. 0.1 μF/16 V Electrolytic Capacitor – 1 No.4.10 nF/16 V Electrolytic Capacitor – 1 No.

5. 10 mH Inductor – 1 No 6. Transistor – SL100 – 1No.

All resistors are carbon / metal film ¼ W 5% unless otherwise specified.

3. THEORY:

The efficiency of output circuit of an amplifier increases as the operation is shifted from class-A to B and then to C. In class-C amplifiers efficiency approaches 100%. But the difficulty with class-C operation is harmonic distortion is more. It is tuned amplifier and only one frequency fo is to be amplified and power to be handled Po is large. Since efficiency is high and harmonic distortion will not be a problem since only one frequency is to be amplified and the tuned circuit will reject the other frequencies.

The function of resonant circuits are:1. To provide correct load impedance to the amplifier.2. To reject unwanted harmonics.3. To couple the power to load

The resonant circuits in tuned power amplifier are called tank circuits.

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4. CIRCUIT DIAGRAM:

5. PROCEDURE:

i. Connect the circuit as shown in diagram.

ii. The input terminals are connected to function generator and output terminals are connected to CRO.

iii. Apply the DC voltage (Vcc) from regulated power supply.

iv. Adjust the input frequency such that output voltage is a perfect since sinusoidal waveform at a fixed frequency..

4.7

k

100nF

10 m H 10nF

10k

+

Vin

+

Vout

Vcc=+5V

SL 100DC INPUT VOLTAGE

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v. Note down corresponding output voltages at different frequencies.

vi. Plot the waveforms of both input and output

vii. The frequency at which the voltage is max and the frequency should be compared with theoretical values.

6. OBSERVATIONS:

The value of Resonant frequency at which maximum gain occurred is _________.

7. CALCULATIONS:

Theoretical value of resonant frequency =____________________

8. GRAPH:

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9. RESULT:

The frequency at which the maximum amplification possible is _________.

10. INFERENCES:

This circuit can be used as class – C tuned power amplifier at the resonant frequency possible is _________________

11. PRECUATIONS:

i. Check the circuit connections before switching on the power supply.

ii. Check the continuity of the connecting wires.

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iii. Power handling capacity of resistor should be kept in mind

iv. Control wires must be checked before use

v. Maximum forward current should not exceed value given in data sheet

vi. Resistors should be connected properly with out interchanging the values.

vii. check all diodes transistors, coils ,with multi meter before putting in circuits.

viii. donot proceed unless you get expected dc voltages.

12. APPLICATIONS:

This is mainly used In radio transmitters and radio receivers

13. EXTENSIONS:

This experiment is conducted with simplest circuit to demonstrate class C operation and small power. To make measurements simple the resonant frequency is chosen around 10 to 20 Khz. In real application class C amplifiers are used at higher power and frequencies of RF range which will call for low values of inductance and high quality capacitors and transistors.

By changing value of the load one can obtain different band width as employed in the circuit used. But real application load is a part of resonant circuit to reflect load on tank circuit to determine Q of the circuit.

Real circuits employing class C operations are found in radio transmitters, ultrasonic cleaners. Radio transmitters operate at 10 to 30 Kwatts employing vaccum tubes.

14. TROUBLE SHOOTING:

S.NO FAULT DIAGNOSIS

1. If no output Check whether C.R.O .

Check if signal around resonance freq

2. Small output Check function generator output.

15. QUESTIONS:

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i. What are the different types of tuned circuits ?

ii. How do you measure DC and AC power in the class C amplifier ?

iii. What is Q of Tuned circuit employed in circuit ?

iv. How is class C operation obtained in this circuit ?

v. State relation between resonant frequency and bandwidth of a Tuned amplifier.

vi. Differentiate between Narrow band and Wideband tuned amplifiers ?

vii. How is harmonic distortion is reduced in class-C Tuned amplifiers?

viii. Sketch current waveform in the transistor..

ix. Calculate bandwidth of a Tuned amplifier whose resonant frequency is 15KHz and Q-factor is 100.

x. Specify the applications of Tuned amplifiers.

EXP.NO.8 VARIABLE SERIES VOLTAGE REGULATOR

Page 46: Eca Lab Manual

1. AIM:

To design a transistorized variable series voltage regulator and study the regulation action for

i. Different values of input voltages

ii Different values of load resistors

And also to find percentage regulation.

2. EQUIPMENTS AND COMPONENTS:

i.APPARATUS

1. CRO (Dual channel)DC-20 MHz 1 No2. Bread Board - ! No. .3. Regulated power supply- 0-30v 1 A, 1 No.4. DMM 3 ½ Digit LCD hand held 1No

ii. COMPONENTS:

1. 1.8kΩ Resistor – 1 No.2. 4.7kΩ Resistor – 1 No.3. 10kΩ Resistor – 1No4. 10kΩ variable Resistor – 1 No5. 1k , 2k , 4.7k, 10k (load resistors ) – 1 No each.6. Zener diode – IN 5253 – 1 No.7. Transistor – SL100 – 2 No.

All resistors are carbon / metal film ¼ W 5% unless otherwise specified.

3. THEORY:

Voltage regulator is a device designed to maintain the output voltage as nearly constant as possible. It monitors the output voltage and generates feed back that automatically increases are decreases the supply voltage to compensate for any changes in output voltage that might occur because of change in load are changes in load voltages.

In transistorized series voltage regulator the control element is a transistor which is in series with load.

The main element used for regulation of output voltage is Zener diode, which must be operated in reverse break down region, where it provides constant voltage irrespective of changes in applied voltages.

The output voltage of the series voltage regulator is Vo = Vz – Vbe.

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Since, Vz is constant, any change in Vo must cause a change in Vbe in order to maintain the above equation. So, when Vo decreases Vbe increases, which causes the transistor to conduct more and to produce more load current, this increase in load causes an increase in Vo and makes Vo as constant. Similarly, the regulation action happens when Vo increases also.

4. CIRCUIT DIAGRAM:

5. PROCEDURE:

i. Connect the circuit as shown in the circuit diagram.ii. Apply the input voltage from power supply.iii. Measure base ,emitter and collector D.C voltages and compare against estimated

values.

Estimated voltages Observed voltagesVb1 ,Vc1, Ve1Vz

iii. For a specific value of load resistor, vary the input voltage from 10 to a maximum of 20 volts and not the values of output voltage.

iv. Change the load resistor and repeat steps 2 and 3.v. Remove the load resistor and note down the voltage at no load.vi. Find percentage regulation.

Percentage regulation =

vii. Plot the graph for load regulation and line regulation.

1.8k

10.0k

10.0k

RL 0.0 V ou t

4.7k

15-30V

SL100

SL100

5.1V

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6. OBSERVATIONS:

S.no Vin Output voltageRL= RL= RL=

7. CALCULATIONS:

Percentage load regulation = =

Percentage Line Regulation = (change in output ) / (change in input) X 100

8. GRAPH:

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9. RESULT:

For RL = ----------------, Regulating range is____________

For RL = ----------------, Regulating range is____________

For RL = ----------------, Regulating range is____________

10. INFERENCES:

This Series Regulator is useful for the input voltage range ______________

11. PRECAUTIONS:

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i. Test Transistors, zener diode before assembling in the circuits.

ii. Apply voltage from 15 V and ensure the DC voltages as shown the circuit are obtained. Check circuit connections and components if expected voltages are not obtained.

iii. Check resistor values properly otherwise power supply may be over loaded due to small values.

iv. If Zener is reversed no damage will occur but output voltage will fall down to 0 V.

v. Don't short the output as this would result in large current through the series transistor which will lead to burning of the same due to overheat.

12. APPLICATIONS:

1. Low current applications. 2. Fixed voltage applications 3. Extension of zener regulator for higher currents.

13. EXTENSIONS:

The main function of voltage regulator is to regulate the changes in output voltage for the changes occur either in input voltage variations or output load variations. In this experiment we have verified for one particular value of output voltage. We can obtain voltage regulation at higher voltages with the help of more number of Zener diode operating in break down region, must be connected in series. For example, to obtain voltage regulation at 8.2 volts, we can use the same circuit with two Zener diodes of values 3.1 volts and 5.1 volts respectively.By employing a series regulator with error amplifier , variable regulated volatage can be obtained from circuit given below.The experiment is conducted is of simplest type to demonstrate use of zener and series pass transistor without any unregulated voltage power supply. In real application regulated power supply used at the input of this experiment will be replaced by a full wave or bridge rectifier with capacitor input filter suitable to the load and repule voltages expected. The series transistor would be a power transistor with high current capacity and would be mounted to heat sink.Ripple can be simulated by change in input and the corresponding change in output at a constant load current.

One can obtain different fixed voltages by suitably changing the zener diode. One can obtain higher current ratings by employing suitable series power transistor and heat sinks.

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14. TROUBLE SHOOTING:

S.NO FAULT DIAGNOSIS

1. If there is no output Check Vcc and all DC voltages. .2.. If DC voltages differ very much Check entire circuit for connections,

resistance values and placementsCheck Transistors.

15. QUESTIONS:

i. Define voltage regulator.

ii. Give the advantages of series voltage regulator. .

iii.. Explain the feed back mechanism in series voltage regulator.

iv. In series voltage regulator which is control element and explain its function.

v. Define load and line regulation. What is ideal value ?.

vi. Which element determines output ripple ?

vii. What determines maximum load current allowed in this circuit ?

viii. Mention the applications of series voltage regulator.

ix. Define no load voltage and full load voltage.

x. Explain the term percentage regulation.

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APPENDIX - I : INTRODUCTION TO INSTRUMENTS USED

1. THE MULTIMETER STRUCTURE

Fig. 1

1. LCD Display: A 3 ½ digit display (maximum reading 1999) indicates measured values, and features symbols indicating ranges, Low battery.

2. Function Selector: To select ACV, DCV, ACA, DCA, Resistance, Diode, Continuity & Transistor test.

3. Input Jacks (VΩ, mA, A and COM): Test leads are inserted into these jacks for Voltage, Resistance, Current measurements, Continuity & Diode checks.

4. Input Socket for Transistor Test: NPN or PNP transistors are inserted in the sockets provided to measure their ratings.

Functional Buttons: Below table indicates the functional button operations

Buttons Operation PerformedPOWER (Yellow Switch) Turn the Meter ON and OFF

Rotate the SWITCH to turn ON the Meter

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Rotate the SWITCH to OFF position to turn OFF the Meter

Display Symbols:

Fig. 2

SYMBOL MEANING1 — Indicates negative reading

2

The battery is low.Warning:

To avoid false readings, which could lead to possible electric shock or personal injury, replace the battery as soon as the battery indicator appears.

3 Indicates the range in which the switch position is placed.

- +

!

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2. FUNCTION GENERATOR

FRONT PANEL CONTROLS

1. Power: Push button switch for supplying power to instrument.2. Digital Display: (7-segment LED): 4-digit frequency / amplitude meter, LED

indicators for Hz, KHz, mV & V.3. FREQ/AMP: Selects display of frequency or amplitude.4. AMP (adjusting knob): Continuous adjustment of the output amplitude from 0 –

20 dB when terminated with 50Ω.5. –20dB, -20dB (Push button): Two fixed attenuators, -20dB each. They can be

used separately. When both push buttons are activated, a total attenuation of –40 dB results. Including the amplitude control for the max. attenuation amounts to 60 dB (factor 1000).

6. Output (BNC connector): Short-circuit-proof signal output of the generator. The output impedance is 50Ω switch selectable. Max output amplitude is 30 Vpp (o.c.) or 15 Vpp when terminated with 50Ω. (Attention! Do not apply any DC voltage to the output socket)

7. 50 Ω / 600 Ω: Push button when pressed selects 600 Ω else 50Ω in released position.

8. DC (On), Offset (adjusting knob): Adjustment of the positive or negative offset voltage. This DC voltage can be superimposed on the output signal. The max offset voltage is ± 12.5 V (o.c.) or ± 6.25 V respectively when terminated with 50Ω. This voltage is also available in DC mode.

9. Function: Mode selection DC- sine triangle – square desired function selection indicated by glowing LEDs.

10. Over drive (LEDs): When working in the offset mode, and the output amplifier is overdriven either in positive or in negative direction, the corresponding LED lit up.

11. FVAR (adjusting knob): Continuous and linear frequency adjustment from 1 Hz to 1 MHz in steps, selected with frequency range.

12. Frequency: Frequency coarse adjustment from 1 Hz to 1 MHz in 7 decade steps. Desired frequency selection indicated by glowing LEDs.

13. VAR: When trigger output is selected in CMOS output can be set with VAR, to approx. 15 Vpp.

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14. Trig output (BNC connector): This short-circuit-proof output supplies square waves signal in synchronous with the output signal. It is switch selectable TTL/CMOS and has a duty-factor or approx 50%.

-x-

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15. TTL/CMOS: Switch selects trigger output TTL or CMOS.16. FM in (BNC connector): Applying a DC voltage to this input will vary the

oscillator frequency linearly to max. 1:100. The maximum allowable input voltage is +30V.

17. AMPL (adjusting knob): Attenuation of input voltage for FM-input. This permits the user to change the sweep width.

TECHNICAL SPECIFICATIONS

Operating Modes:Sine – Square – Triangle – DC, Free running or external frequency modulated, with or without DC offset.

Frequency Range:0.1 Hz – 1 MHz in 7 decade steps variable control between steps.

Waveform Characteristics

Sine wave distortion: 0.1 Hz to 100 KHz : max. 0.5%100 KHz to 500 KHz : max. 1.5%500 KHz to 1 MHz : max. 3%

Square wave rise time:Max. 70ns (10 to 90%)

Overshoot:≤5% (when output is terminated with 50 Ω

Triangle Non-linearity:≤1% (upto 100 kHz) approx.

Display:

Display switch able for frequency and amplitude, with automatically positioned decimal point LED indicator for Hz, KHz, mV and V.

Frequency:4 digit 7 segment LEDup to 100 KHz : ± 1% ±LSDup to 1 MHz : ± 3% ±LSD

Amplitude:3 digit 7 segment LED

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Accuracy:3Vpp-30Vpp : ± 3%300mVpp – 3Vpp : ± 5%30mVpp – 300mVpp : ± 5%

Amplitude:3 digit 7 Segment LED

Accuracy:3Vpp – 30Vpp : ± 3%300mVpp – 3Vpp : ± 5%30mVpp – 300mVpp : ± 5%

Overdrive:Indicates with two LEDs

-xi-

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Outputs:Signal output : short-circuit proofImpedance : 50 Ω / 600 Ω switch ableOutput voltage: max. 15 Vpp into 50Ω, 30 Vpp open circuitAttenuation : 2 steps: 20dB ± 0.2dB each. Variable attenuation:

0 to 20 dB total of 60dBAmplitude Flatness: (sine/triangle) with 50 Ω termination.

0.1 Hz to 100 KHz max. 0.2 dB100 KHz to 1 MHz max. 0.5 dB

DC offset : Continuously variable (switch able)Offset range : max. ± 6.25 V into 50Ω

Max. ± 12.5 V open circuitTrigger output: Switch selectable TTL/CMOS TTL more than 4V CMOS level

adjustable up to 14V (approx.)

FM input / External Sweep:Frequency change : approx. 1 : 100Input Impedance : 100kΩ || 25pFInput voltage : max ± 30 Vpp

General Information:Supply : 220 V AC ± 10%, 50 HzPower Consumption : 20 VA (approx.)Operating Conditions : 0-50˚C, 95% RHDimensions (mm) : W196 x H80 x D 262Weight : 2.5 kg (approx.)

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-xii-

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3. CATHODE RAY OSCILLOSCOPE

TECHNICAL SPECIFICATIONS

Operating modes:Channel I, Channel II, Channel I & II alternate / chopped (approx. 500 KHz) X – Y (Ratio 1:1 input via CH II), Add/Sub, Invert CH II.Vertical deflection (y): (Identical channels)Bandwidth:DC-20 MHz (-3 dB)DC-28 MHz (-6dB)Rise Time: 17.5 ns (approx.)Deflection coefficients:12 calibrated steps 2mV/cm – 10V/cm (1-2-5 sequence)Accuracy: ± 3%Input Impedance: 1 MΩ || 25 pF.Input coupling: DC-AC-GNDInput voltage: Max. 400V (DC + Peak AC).

Time base:Time coefficients: 18 calibrated steps. 0.5 s/cm – 0.2s/cm (1-2-5 sequence) with magnifier x 5 to 100ns/cm. With variable control to 40 ns/cm.Accuracy: ± 3% (in cal position)Ramp output: 5 Vpp (approx.)Hold-Off: Variable control for stable trigger.

Trigger System:Modes: automatic or variable trigger levelSource: Ch I, Ch II, ALT Ch I / Ch II, Line, Ext.Slope: Positive or NegativeCoupling: ACSensitivity: Int. 5mm, Ext 0.8 V (approx.)Trigger Bandwidth: 40 MHz

Horizontal Deflection (x):Bandwidth: DC – 2.3 MHz (-3 dB).X – Y mode: Phase shift < 3˚ at 60 KHz.Deflection coefficients: 12 calibrated steps 2mV/cm-10V/cm(1-2-5 sequence)Input Impedance: 1 M Ω || 25 pF.

Component Tester:Test Voltage: Max 8.6 Vrms (Open)Test Current: Max 8 mA rms (Shorted)Test Frequency: 50Hz, Test circuit grounded to chassis.

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Continuity Tester:Beeper sounds < 75Ω (approx.)

General Information:

Cathode Ray Tube: Rectangular medium short persistence (P-31)

Accelerating potential: 2000 VDC (approx.)

Display: 8 x 10 cm

Trace rotation: Adjustable on front panel

Calibrator: Square wave generator 1KHz (approx.). 0.2V ±1% for probe compensation.

Z Modulation: TTL level

Stabilized Power Supply: All operating voltages including the EHT

Mains Voltage: 220 V, 50Hz

Mains fluctuations: ±10% (max.)

Power Consumption: 33 VA (approx.)

Weight (approx): 7.5 kg.

Dimensions (mm): W285 x H145 x D380

Operating Temperature: 0-40˚, 95% RH

Finish: Off white with handle and tilt stand.

SPECIFICATION FOR LOGIC SCOPE :

Logic Inputs: 8 Nos. (TTL timing diagrams)

Output: To oscilloscope.

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PANEL CONTROLS

1 Power On/Off Push buttons switch for supplying power to instrument.2 X5 Switch when pushed inwards gives 5 times

magnification of the X signal.3 XY Switch when pressed cuts off the time base & allows

access the ext. horizontal signal to be fed through CH II (used for X-Y display)

4 CH-I/CH-II Trig I/Trig II Switch when out selects & triggers CH I and when pressed, selects & triggers CH II.

5 Mono/Dual Switch selects the dual operation6 ALT/CHOP/ADD Switch selects alternate or chopped in DUAL mode. If

mono is selected then this switch enables addition or subtraction of channel i.e. CHI ± CHII

7 Time/Div Switch selects time base speeds8 AT/Norm Switch selects Auto/Normal position. Auto is used to

get trace when no signal is fed at the input. In NORM the trigger level can be varied from the positive peak to negative peak with LEVEL control

9 Level Controls the trigger level from peak to peak amplitude of signal

10 Trig. Input Socket provided to feed external trigger signal in EXT. mode

11 Cal out Socket provided for square wave output 200 m V; used for probe compensation and checking vertical

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sensitivity, etc.12 Hold Off Controls hold of time between sweeps. Normal position

= full ccw13 X-POS Controls Horizontal position of the trace14 Ext. Switch when pressed allows external triggering signal to

be fed from the socket marked TRIG. INP.

-xv-

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15 Variable Controls the time speed in between two steps of TIME/DIV switch. For calibration put this fully anticlockwise. (At CAL pos)

16 Line Switch when pressed displayed signal gets synchronized with mains line frequency

17 Alt Selects alternate trigger mode from CH I & CH II18 + / - Switch selects the slope of triggering, whether positive

going or negative going19 Inv Ch. II Switch when pressed inverts the CH II20 Intensity Controls the brightness of the trace21 TR Controls the alignment of the trace with gratitude

(Screw driver adjustment)22 Focus Controls the sharpness of the trace23 CT Switch when pressed starts CT operation24 DC/AC/GD Input coupling switch for each channel. In AC the signal

is coupled through 0.1 MFD capacitor.25 Ch. I(Y) & Ch. II(X) BNC connectors serve as input connection for CH I &

CH II Channel II input connector also serves as Horizontal external signal.

26 CT-IN To test any components in the CT mode, put one test probe in this socket and connect the other test probe in ground socket.

27 Volts/Div Switches select the sensitivity of each channel28 Y POS I & II Controls provided for vertical deflection of trace for

each channel.LOGIC SCOPE

29 Inputs Terminals provided for feeding logic levels (Timing Diagram) use 1 mm patch cords (bunch of 8)

30 Output Connect output to CH I or CH II of oscilloscope by using 1 mm patch cord

Back Panel Controls31 Fuse 350 mA fuse is provided at the back panel. Spare fuses

are provided inside the instrument32 Z mod Banana socket provided for modulating signal input i.e.

Z-modulation.

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4. REGULATED POWER SUPPLY

1. POWER:Push button switch for supplying power to instrument.

2. OUTPUT ON:Push button for switching On / Off all the three output voltages.

3 & 6 V/mA (Push button):For switching the display from voltage to current reading or vice versa. When pushbuttons are pressed, the current supplied from the terminals 12 & 17 is displayed with a resolution of 1mA. In released position voltages across the terminals 12 & 17 are displayed with a resolution of 0.1 V.

4 & 7 DIGITAL DISPLAYS (7-Segment LED):Dual display with two 3-digit readout for output voltage and current. On the left side of the instrument the voltage and current readings for terminals 3 is indicated. The corresponding values for the terminals 4 are indicated on the right side of the display.

5 & 8 V & mA INDICATORS:

Two LEDs indicate the unit of the display. The mA LED flashes when the 0 – 30VDC output is used in constant current mode, or output current required is in excess of specified value, in CV mode.

9 OUTPUT + 5 V (fixed) (4mm banana sockets):

Output terminals for 4mm banana plugs or cable connection for the fixed +5V output. The output voltage is short circuit protected.

Page 66: Eca Lab Manual

DC Output:

2 x 0 – 30V, 500 mA

1 x 5V fixed, 1A

Output Voltage Range:

0-30V, continuously variable by means of coarse and fine controls

Resolution: ≤ 0.1%

Internal resistance: ≤ 15mΩ (typical 7mΩ)

Stability: ≤ 2.5mV (max.: 2 x 200mA) at line voltage variations of up to 10%

Recovery time: ≤ 80s

Load regulation: ≤ 0.05%

Temperature coefficient: ≤ 0.1%/˚C

Ripple and noise: ≤ 1mVrms

Output current: max. 500 mA

Current limit: 10mA to 500mA continuously adjustable

Resolution: ≤1%

+5V Fixed Output

Tolerance: ± 0.2V

Internal resistance: ≤ 0.06Ω

Stability: ≤ 5mV at line voltage variations of up to 10%

Recovery time: ≤ 100 s

Temperature coefficient: ≤ 0.1%/˚C

Ripple and noise: ≤ 5mVrms

Output current: max. 1A

Display

2 x 3-digit 7-segment LED display for Voltage & Current. Two LED (for V and mA) indicate the unit of display.

Page 67: Eca Lab Manual

General Information

All outputs are floating. Outputs are switch able from front panel.

Built-in overheat protection.

Supply: 230 V AC ± 10%, 50 Hz

Operating Conditions: 0-40˚C, 95% RH

Dimension (mm): W 196, H80, D262

Weight: 3.9 Kgs

Page 68: Eca Lab Manual

APPENDIX II

GENERAL PRECAUTIONS IN ASSEMBLING CIRCUITS :

i. 100 percent knowledge about color code of Resistors is required.

ii. Full knowledge about bread board and contact information is required.

iii. 100 percent knowledge about transistor lead connections i.e. base , emitter and collector connections.

iv. 100 percent knowledge about diode and zener lead connections i.e. anode and cathode connections.

v. Polarity marking of the electrolytic capacitors must be observed , while connecting.

vi. It will be a good practice to test diodes and transistors with DMM before using .

vii. Test connecting leads and probes before using.

viii. After completing assembly – before connecting RPS , ensure that supply and ground leads of the circuit are not shorted . This can be verified by multi meter .

Page 69: Eca Lab Manual

APPENDIX III :

GENERAL PRECAUTIONS IN USING INSTRUMENTS :

Regulated Power supply :

i. Before connecting RPS , ensure that supply and ground leads of the circuit are not shorted . This can be verified by multi meter .

ii. Set voltage controls to zero reading , before connecting to the circuit.

iii. Set current setting to mid or less than the mid position.

CRO :i. Obtain trace on channel and set position control to get the trace to the

middle .ii. See to which channel you are applying input .

iii. Touch the probe with hand to know whether it is responding. This will detect broken probes , wrong setting of channels .

iv. Set volts/div and time/div as required.

v. AC and DC coupling of input , positive / negative level settings must be understood.

vi. Generally CRO must in AUTO mode of sweep.

vii. Learn how to trigger the CRO and set controls to get stable trace and full control with level and slope .

viii. One should also know component tester mode of CRO.

FUNCTION GENERATOR :

i. Set the output controls to minimum before connecting to circuit.

ii. Select sine / square / triangular waveform with desired frequency .

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iii. One should know attenuator , DC offset settings and output terminals properly.

MOVING COIL AMMETERS AND VOLTMETERS :

i. polarity of connections to above must be perfectly correct, otherwise meters will be damaged due to wrong connections.

ii. The proper ( Full Scale reading )rated meters must be used , otherwise meters will be damaged by over currents / voltages.

DIGITAL MULTIMETERS :

i. Before connecting and switching on , set to proper function i.e. V-A-R ac or dc and range .

ii. Applying voltages in resistance mode will damage DMM’s.

iii. Turning knobs with voltages / currents ON will damage DMM’s.

iv. SET THE RANGE AND APPLY VOLTAGE OR CURRENT.

Page 71: Eca Lab Manual

APPENDIX – IV :

Specifications of BC 107:

Collector –base voltage (open emitter), VCBO max = 60V

Collector – emitter voltage (open base), VCEO max. = 45V

Emitter base voltage (open collector) VEBO max = 5 V

Collector current (d.c.) IC max = 200mA

Total Power dissipation , Ptot max = 250 mW

Max. Junction temperature at 25 oC = 150 oC

Forward Current Gain = 150

Specifications of SL100 :

Collector –base voltage (open emitter) VCBO max = 60V

Collector – emitter voltage (open base) VCEO max. = 45V

Emitter base voltage (open collector) VEBO max = 5 V

Collector current (d.c.), IC max = 1A

Total Power dissipation, Ptot max = 2W

Max. Junction temperature at 25 oC = 150 oC

Forward Current Gain = 20

Page 72: Eca Lab Manual

SPECIFICATIONS OF ZENER DIODE IN5253 :

Working Zener voltage range, Vz = 4.7 to 33 volts

Maximum power consumption at room temp. P max = 300mW

Maximum Junction temp. T max = 1500C

Page 73: Eca Lab Manual

APPENDIX IV :

SPICE PROGRAMS OF ECA LAB EXPERIMENTS :

1. TWO STAGE RC COUPLED CE AMPLIFIER :

** two stage RC coupled amplifiervcc 4 0 dc 12vvin 1 0 ac 50mvrb1 1 2 4.7kcb1 2 3 10ur11 3 4 62kr12 3 0 4.7krc1 4 5 33kre1 6 0 560ce1 6 0 10uq1 5 3 6 bc107.model bc107 npn (bf=100)cc1 5 7 0.1urb2 7 8 1kr21 8 4 62kr22 8 0 4.7krc2 9 4 33kre2 10 0 560ce2 10 0 10ucc2 9 11 10uq2 9 8 10 bc107a .model bc107a npn (bf=100)rl 11 0 1kcsh 11 0 5n.ac dec 10 50hz 100khz.print ac v(11).plot ac V(11).probe.end

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1.B. ALTERNATE TWO STAGE RC COUPLED AMPLIFIER

**alternate circuit for two stage RC coupled CE amplifiervin 0 12 ac 10mv sin(0 10mv 15khz)rb 12 1 10kcb1 1 2 10uvcc 5 0 dc 12vr11 2 5 47kr12 2 0 10krc1 3 5 2.2kre1 4 0 1kce1 4 0 100uq1 3 2 4 bc107.model bc107 npn (bf=100)cc1 3 6 10urb2 6 0 10kcb2 7 8 10urb1 6 7 10kr21 8 5 47kr22 8 0 10krc2 9 5 2.2kre2 10 0 1kce2 10 0 100uq2 9 8 10 bc107a.model bc107a npn (bf=100)cc3 9 11 10url 11 0 2.2kcsh 11 0 2n.ac dec 10 10hz 100khz.print ac v(11).plot ac V(11).probe.end

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2. SIMPLE SERIES VOLTAGE REGULATOR :

**SERIES VOLTAGE REGULATOR vin 1 0 dc 20v r1 1 2 560r2 2 3 1kq1 2 3 4 sl100 .model sl100 npn ( bf=20)d1 0 3 dname .model dname d(bv=5.1v)rl 4 0 1k.dc vin 0 30v 1v.plot dc v(4) v(1).print dc v(4) v(1).probe.end

3.SHUNT VOLTAGE REGULATOR :

**SHUNT VOLTAGE REGULATOR VIN 1 0 20VR1 1 2 560 Q1 2 4 3 SL100A .MODEL SL100A NPN (BF=20)Q2 2 3 0 SL100B.MODEL SL100B NPN (BF=20)D1 4 2 DNAME.MODEL DNAME D(BV=6.8V)R2 4 0 1KRL 2 0 1K.dc vin 0 30v 1v.plot dc v(2) v(1).print dc v(2) v(1).probe.end

Page 76: Eca Lab Manual

3A . SIMPLE SHUNT VOLTAGE REGULATOR

**simple shunt voltage regulator vin 1 0 20vr1 1 2 180d1 3 2 dname .model dname d(bv=6.8v)q1 2 3 0 sl100.model sl100 npn (bf=20)r2 3 0 1krl 2 0 2k.dc vin 0 30v 1v.plot dc v(2) v(1).print dc v(2) v(1).probe.end

4. SERIES FED CLASS – A POWER AMPLIFIER :

**series fed class-A power amplifiervcc 3 0 dc 5vvin 1 0 sin(0 10mv 1khz)rb 3 2 20kc1 1 2 0.1urc 3 4 1kq1 4 2 0 sl100.model sl100 npn (bf=20)c2 4 5 0.1url 5 0 1k.tran 10us 10ms 10us.print dc i(rc).probe.end

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5. COMPLIMENTARY – SYMMETRY CLASS – B POWER AMPLIFIER :

** complimentary symmetry class-B power amplifiervin 1 0 sin(0 2v 1khz)q1 3 2 4 sl100.model sl100 npn (bf=20)q2 5 2 4 sk100.model sk100 pnp (bf=20)c1 1 2 1url 4 0 8vcc 3 0 5vvee 0 5 5v.tran 10us 2ms 10us.probe.end

6. ALTERNATE CIRCUIT FOR CLASS-B COMPLIMENTARY SYMMETRY POWER AMPLIFIER

**alternate circuit for class-B com-sym power amplifiervin 1 0 sin(0 2v 10khz)r1 1 2 1kc1 2 3 0.1uc2 2 4 0.1ur2 3 5 220kr3 3 0 18kr4 4 0 18kr5 4 9 220kvee 0 9 dc 12vvcc 5 0 dc 12vq1 5 3 6 sl100 .model sl100 npn (bf=20)q2 9 4 8 sk100.model sk100 pnp (bf=20)r6 6 7 4.3r7 8 7 4.3rl 7 0 1k.tran 10us 2ms 10us.probe.end

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7. CLASS – C TUNED POWER AMPLIFIER :

**class - C tuned power amplifiervin 1 0 ac 2v sin(0 2v 15.9khz)vcc 4 0 dc 5vc1 1 2 0.1ur1 2 0 4.7kq1 3 2 0 sl100.model sl100 npn (bf=20)l1 4 3 10mhc2 4 3 10nrl 3 0 10k.ac dec 100 1khz 100khz.tran 10us 2ms 10us.probe.end

8. VARIABLE SERIES VOLTAGE REGULATOR :

** variable series voltage regulator vin 1 0 dc 20vr1 1 2 4.7kr2 1 4 1.8kr3 3 5 10kr4 5 0 10krl 3 0 2kq1 1 2 3 sl100a .model sl100a npn (bf=20)q2 2 5 4 sl100b .model sl100b npn (bf=20)d1 0 4 dname .model dname d(bv=5.1v).dc vin 0 30v 1v.print dc v(1) v(3).plot dc v(1) v(3).probe.end


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