lab manual ece lab1-ece2201- sem i 2008 2009

8/6/2019 Lab Manual ECE Lab1-ECE2201- Sem I 2008 2009

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ECE 2201

Electrical & Computer Engineering Lab I

Electronic Circuits

Lab Manual

Semester I 2008/2009


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LAB V

SAFETY

Safety in the electrical laboratory, as everywhere else, is a matter of the knowledge of potential

hazards, following safety precautions, and common sense. Observing safety precautions is important

due to pronounced hazards in any electrical/computer engineering laboratory. Death is usually certainwhen 0.1 ampere or more flows through the head or upper thorax and have been fatal to persons withcoronary conditions. The current depends on body resistance, the resistance between body and

ground, and the voltage source. If the skin is wet, the heart is weak, the body contact with ground islarge and direct, then 40 volts could be fatal. Therefore, never take a chance on "low" voltage. When

working in a laboratory, injuries such as burns, broken bones, sprains, or damage to eyes are possible

and precautions must be taken to avoid these as well as the much less common fatal electrical shock.

Make sure that you have handy emergency phone numbers to call for assistance if necessary. If anysafety questions arise, consult the lab demonstrator or technical assistant/technician for guidance and

instructions. Observing proper safety precautions is important when working in the laboratory to

prevent harm to yourself or others. The most common hazard is the electric shock which can be fatalif one is not careful.

Acquaint yourself with the location of the following safety items within the lab.

a. fire extinguisher

b. first aid kitc. telephone and emergency numbers

ECE Department 03-2056 4530

Kulliyyah of Engineering Deputy

Deans Student Affairs03-2056 4447

IIUM Security 03-2056 4172

IIUM Clinic 03-2056 4444

Electric shock

Shock is caused by passing an electric current through the human body. The severity depends mainlyon the amount of current and is less function of the applied voltage. The threshold of electric shock isabout 1 mA which usually gives an unpleasant tingling. For currents above 10 mA, severe muscle

pain occurs and the victim can't let go of the conductor due to muscle spasm. Current between 100

mA and 200 mA (50 Hz AC) causes ventricular fibrillation of the heart and is most likely to be lethal.


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What is the voltage required for a fatal current to flow? This depends on the skin resistance. Wet skincan have a resistance as low as 150 Ohm and dry skin may have a resistance of 15 kOhm. Arms andlegs have a resistance of about 100 Ohm and the trunk 200 Ohm. This implies that 240 V can cause

about 500 mA to flow in the body if the skin is wet and thus be fatal. In addition skin resistance falls

quickly at the point of contact, so it is important to break the contact as quickly as possible to prevent

the current from rising to lethal levels.

Equipment grounding

Grounding is very important. Improper grounding can be the source of errors, noise and a lot of

trouble. Here we will focus on equipment grounding as a protection against electrical shocks. Electricinstruments and appliances have equipments casings that are electrically insulated from the wires thatcarry the power. The isolation is provided by the insulation of the wires as shown in the figure a

below. However, if the wire insulation gets damaged and makes contact to the casing, the casing will

be at the high voltage supplied by the wires. If the user touches the instrument he or she will feel thehigh voltage. If, while standing on a wet floor, a user simultaneously comes in contact with the

instrument case and a pipe or faucet connected to ground, a sizable current can flow through him or

her, as shown in Figure b. However, if the case is connected to the ground by use of a third (ground)wire, the current will flow from the hot wire directly to the ground and bypass the user as illustrated infigure c.

Equipments with a three wire cord is thus much safer to use. The ground wire (3rd wire) which is

connected to metal case, is also connected to the earth ground (usually a pipe or bar in the ground)

through the wall plug outlet.

Always observe the following safety precautions when working in the laboratory:

1. Do not work alone while working with high voltages or on energized electrical equipment orelectrically operated machinery like a drill.


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2. Power must be switched off whenever an experiment or project is being assembled, disassembled,or modified. Discharge any high voltage points to grounds with a well insulated jumper.

Remember that capacitors can store dangerous quantities of energy.

3. Make measurements on live circuits or discharge capacitors with well insulated probes keepingone hand behind your back or in your pocket. Do not allow any part of your body to contact anypart of the circuit or equipment connected to the circuit.

4. After switching power off, discharge any capacitors that were in the circuit. Do not trustsupposedly discharged capacitors. Certain types of capacitors can build up a residual charge after

being discharged. Use a shorting bar across the capacitor, and keep it connected until ready for

use. If you use electrolytic capacitors, do not :

put excessive voltage across them

put ac across them

connect them in reverse polarity

5. Take extreme care when using tools that can cause short circuits if accidental contact is made toother circuit elements. Only tools with insulated handles should be used.

6. If a person comes in contact with a high voltage, immediately shut off power. Do not attempt toremove a person in contact with a high voltage unless you are insulated from them. If the victim isnot breathing, apply CPR immediately continuing until he/she is revived, and have someone dialemergency numbers for assistance.

7. Check wire current carrying capacity if you will be using high currents. Also make sure yourleads are rated to withstand the voltages you are using. This includes instrument leads.

8. Avoid simultaneous touching of any metal chassis used as an enclosure for your circuits and anypipes in the laboratory that may make contact with the earth, such as a water pipe. Use a floatingvoltmeter to measure the voltage from ground to the chassis to see if a hazardous potential

difference exists.

9. Make sure that the lab instruments are at ground potential by using the ground terminal suppliedon the instrument. Never handle wet, damp, or ungrounded electrical equipment.

10. Never touch electrical equipment while standing on a damp or metal floor.

11. Wearing a ring or watch can be hazardous in an electrical lab since such items make goodelectrodes for the human body.

12. When using rotating machinery, place neckties or necklaces inside your shirt or, better yet,remove them.

13. Never open field circuits of D-C motorsbecause the resulting dangerously high speeds may causea "mechanical explosion".

14. Keep your eyes away from arcing points. High intensity arcs may seriously impair your vision ora shower of molten copper may cause permanent eye injury.

15. Never operate the black circuit breakers on the main and branch circuit panels.

16. In an emergency all power in the laboratory can be switched off by depressing the large redbutton on the main breaker panel. Locate it. It is to be used for emergencies only.


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17. Chairs and stools should be kept under benches when not in use. Sit upright on chairs orstools keeping the feet on the floor. Be alert for wet floors near the stools.

18. Horseplay, running, or practical jokes must not occur in the laboratory.

19. Never use water on an electrical fire. If possible switch power off, then use CO2 or a drytype fire extinguisher. Locate extinguishers and read operating instructions before anemergency occurs.

20. Never plunge for a falling part of a live circuit such as leads or measuring equipment.

21. Never touch even one wire of a circuit; it may be hot.

22. Avoid heat dissipating surfaces of high wattage resistors and loads because they can cause severeburns.

23. Keep clear of rotating machinery.

Precautionary Steps Before Starting an Experiment so as Not to Waste Time Allocated

a) Read materials related to experiment before hand as preparation for pre-lab quiz andexperimental calculation.

b) Make sure that apparatus to be used are in good condition. Seek help from techniciansor the lab demonstrator in charge should any problem arises.

Power supply is working properly ie Imax (maximum current) LED indicator isdisable. Maximum current will retard the dial movement and eventually damagethe equipment. Two factors that will light up the LED indicator are short circuitand insufficient supply of current by the equipment itself. To monitor and

maintain a constant power supply, the equipment must be connected to circuitduring voltage measurement. DMM are not to be used simultaneously with

oscilloscope to avert wrong results.

Digital multimeter (DMM) with low battery indicated is not to be used. By properconnection, check fuses functionality (especially important for current

measurement). Comprehend the use of DMM for various functions. Verifymeasurements obtained with theoretical values calculated as it is quite often

where 2 decimal point reading and 3 decimal point reading are very much

deviated.

The functionality of voltage waveform generators are to be understood. Makesure that frequency desired is displayed by selecting appropriate multiplier knob.

Improper settings (ie selected knob is not set at minimum (in direction of CAL

calibrate) at the bottom of knob) might result in misleading values and henceincorrect results. Avoid connecting oscilloscope together with DMM as this will

lead to erroneous result.

Make sure both analog and digital oscilloscopes are properly calibrated bypositioning sweep variables for VOLT / DIV in direction of CAL. Calibration can

also be achieved by stand alone operation where coaxial cable connects CH1 tobottom left hand terminal of oscilloscope. This procedure also verifies coaxialcable continuity.

c) Internal circuitry configuration of breadboard or Vero board should be at studentsfingertips (ie holes are connected horizontally not vertically for the main part with

engravings disconnecting in-line holes).


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d) Students should be rest assured that measured values (theoretical values) of discretecomponents retrieved ie resistor, capacitor and inductor are in accordance therequired ones.

e) Continuity check of connecter or wire using DMM should be performed prior toproceeding an experiment. Minimize wires usage to avert mistakes.

f) It is unethical and unislamic for students to falsify results as to make them appearexactly consistent with theoretical calculations.


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LAB VI

EXPERIMENT 1

SMALL SIGNAL CE AMPLIFIERS

1. OBJECTIVE To demonstrate the ac operation of the common-emitter (CE) amplifier.

To demonstrate the effects that a bypass capacitor has on amplifier voltage gain (Av).

2. DISSCUSSIONThe input signal to a CE amplifier is applied across the base-emitter junction of the device. Theoutput from this circuit is taken from the collector terminal of the transistor. The CE amplifier is oneof the most commonly used BIT amplifier configurations. The amplifier has a relatively high voltagegain, a relatively high current gain, and a voltage phase shift of 180 0 between its input (base) andoutput (collector) terminals. In this exercise, you will observe the ac operation of the CE amplifier.You will also observe the effects of the emitter bypass capacitor,a component used to increase thevoltage gain of the CE amplifier.

Figure 1

3. MATERIALS1 Variable dc power supply

1 Variable ac signal generator

1 Dual-trace oscilloscope1 DMM

1 2N3904 npn transistor

5 Resistors: 390 , 1.5 k , 2.2 k , 3.3 k , and 100 k1 50-k Potentiometer

2 10- F Electrolytic capacitors

1 100- F Electrolytic capacitor


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4. USEFUL FORMULASVA =

in

out

V

V

VA =e

C

r

r

5. PROCEDUREA. Construct the circuit shown in fig. 1.B. Apply power to the circuit and adjustR1ato provide midpoint bias.C. For future reference, measure and record the value ofVC and VE.

Vc =

VE=D. Apply a 1-kHz, 20-m Vpp ac signal to the input of the amplifier.

Note: You should set the signal generator so that you have 20 m VPP at the base terminal ofthe transistor (measured with respect to ground).

E. Measure and record the peak-to-peak output voltage at the collector terminal of the transistor.

Vout = Vpp.

F. Using the values measured in steps 4 and 5, calculate the voltage gain of the amplifier.

Av=

G. The coupling capacitors in an amplifier are used to block dc while coupling an ac signal. Inother words, when you have an ac signal with some measurable dc average on one side of the

capacitor, you should get only the ac signal on the other side. The dc average of the signal

should be eliminated. Using your dc voltmeter, measure the dc average of the ac signal on the

transistor side of CC2.

Vave = on the transistor side of CC2.H. Measure and record the dc average of the ac signal on the load side of CC2.

Vave = on the load side of CC2I. Do your measurements support the statement that a coupling capacitor passes ac while

blocking dc?

J. It was stated in the Discussion section of this exercise that the CE amplifier produces a 1800

voltage phase shift from input (base) to output (collector). Connect channel 1 of youroscilloscope to the base of the transistor and channel 2 to the collector. Adjust the vertical

sensitivity of your channels so that each signal fills approximately four major divisions on theCRT. Neatly draw the display on your oscilloscope on the grid provided.


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K. Remove the emitter bypass capacitor and repeat steps 4, 5, and 6 of the procedure.

Vin = Vpp

Vout = Vpp

Av =

L. What happened toAvwhen the bypass capacitor was removed? Why?

QUESTIONS AND PROBLEMS

1) The voltage gain of a CE amplifier, employing an emitter bypass capacitor, can be found as

VA =e

C

r

r

Where Cr = CR || LR

Another form of this equation allows us to calculate the ac resistance of the emitter (r'e) asfollows:

er=V

C

A

r

Using the measured value ofAv(from step 6 of the procedure) and the value ofrc,calculate thevalue ofr'e.

r'e=


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2) The value ofr'ecan be approximated as

r'e =

EI

mV25

Where

E

EE

R

VI =

Using your circuit values and this equation, calculate the value of r'e .

re =

3) What is the percent of error between the two values ofre thatyou have calculated?

% of error =How would you account for this percent of error?

4) Which value of r e do you believe to be more accurate? Explain your answer.

5) When the emitter resistor is not bypassed, the voltage gain of a CE amplifier can be approximatedas

E

CVR

rA =

Using the rated values ofRC, RL,andRE,calculate the value ofAvfor the unbypassed circuit.

Av=6) Calculate the percent of error between the calculated value ofAv(question 5) and the measured

value (procedure step 11).

% Of error =How would you account for this percent of error?

7) With respect to circuit bias, why is it important to block the dc reference of the signal, as youobserved in steps 7 and 8?


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LAB VII

EXPERIMENT 2

SMALL SIGNAL CS AMPLIFIERS

1. OBJECTIVES To demonstrate the ac operation of a typical common-source amplifier.

To demonstrate the differences between the ac operating characteristics of a typical JFETamplifier and those of a typical BJT amplifier

2. DISCUSSIONThere are several similarities between the common-source (CS) amplifier and the common-emitter(CE) amplifier. Both amplifiers provide a measurable amount of voltage gain. Both amplifiers have a

1800

voltage phase shift between the input and output terminals. At the same time, there are several

differences between the two amplifier types. Perhaps the biggest difference is that JFETs are voltage-controlled devices while BJTs are current-controlled devices. The CS amplifier typically has much

higher input impedance than the CE amplifier. Also, the voltage gain calculation for a CS amplifier isdifferent from the CE voltage gain calculation. In this exercise, you will observe the operation of aself-biased CS amplifier. While analyzing this exercise, you should pay close attention to those points

of operation that distinguish the CS amplifier from the CE amplifier.

Figure.1

3. MATERIALS1 Variable dc power supply1 Variable ac signal generator

1 Dual-trace oscilloscope

1 VOM or dc milliammeter1 DMM1 2N5485 n-channel JFET

2 Resistors: 4.7 k and 1 M2 Potentiometers: 5 k and 2.0 M

2 Capacitors: 0.022 F and 22 F


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4. USEFUL FORMULASAv =gmrD

in

outV

v

vA =

5. PROCEDUREA. Construct the circuit in Fig.1. RS should be set initially to 1 k .B. The value of gm for a JFET is found as

GS

Dm

V

Ig

D=

In this step, you will determine the value of gm for your JFET as follows:

With RS set to 1 k , measure and record the following:

VGS =

ID =

Power down and adjust Rs to a value of 1.5 k . Power up the circuit and measure and

record the following:

VGS=

ID =

Calculate the following:

VGS= VGS(max)- VGS(min) =

ID=ID(max) -ID(min) =

gm=

GS

D

V

I

D

D =

C. Using the rated value ofRD, calculate the open-load voltage gain of your amplifier.

Av=

D. SetRS to approximately 1.3 k .E. Set the amplitude of your signal generator to minimum. Set the output frequency of your

signal generator to approximately 1 kHz.

F. Connect your oscilloscope to the output of the amplifier. Then increase the amplitude of theinput signal until you get the maximum undistorted output from the amplifier. Measure andrecord the following:

Vout= Vpp

Vjn = Vpp

G. Using the values obtained in step F, calculate the value of A v for your amplifier.

Av=


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H. Adjust the vertical sensitivity of your oscilloscope channels so that you can observe both theinput and output waveforms on the CRT at the same time. Then neatly draw the twowaveforms in their proper phase relationships on the grid provided.

Note: For steps I through K, use the l0 position on the scope probes.

I. Without disturbing the amplitude setting or your signal generator, insert the 2 Mpotentiometer between the generator output and the input coupling capacitor.

J. Adjust the 2 M potentiometer until the output from the amplifier has an amplitude that isone-half of its original value.

K. Without disturbing the potentiometer setting, remove it from the circuit and measure itsresistance. This is approximately equal to the input impedance of the amplifier.

R Zjn=


1) Calculate the percent of error between the values of Av obtained in steps 3 and 7 of the procedure.

% of error =How would you account for this error?

2) Calculate the percent of error between the measured input impedance of the amplifier and therated value ofRG.

% Of error =

Why wasn't the input impedance of the JFET considered in the percent of error calculation?

3) Discuss, in your own words, what you observed in this exercise.


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LAB VIII

EXPERIMENT 3

INVERTING AMPLIFIERS

1. OBJECTIVES To demonstrate the operation of the inverting amplifier.

To demonstrate the effect of resistor faults on the operation of the inverting amplifier.

2. DISCUSSIONThe inverting amplifier is very similar in several respects to the common-emitter (CE) and common-source (CS) amplifiers. Like the CE and CS circuits, the inverting amplifier produces a 1800voltage

phase shift between its input and output terminals. Inverting amplifiers can also be designed for awide range of voltage gains. At the same time, the inverting amplifier has many characteristics that

make it more desirable than either the CE or CS amplifiers:

i. Inverting amplifiers are capable of extremely high voltage gains, up to 100,000 and higher inmany cases.

ii. The gain of an inverting amplifier is extremely stable and easy to calculate.iii. Inverting amplifiers are easier and often cheaper to design and troubleshoot than either CE or

CS amplifiers.

Since this is probably your first exposure to working with integrated-circuit (IC) op-amps, there are afew points that should be made:

i. The +V and -V pins mustbe connected to their respective supply voltages for the op-amp towork.

ii. Pin 1 is identified by an indentation in the IC package, as shown below. When the indentationis on the left, pin 1 is at the lower-left corner of the IC. The rest of the pins are numbered in

sequence, going counterclockwise from pin 1.iii. The op-amp will not work if either the inverting (pin 2) or the noninverting (pin 3) inputs are

left open.

iv. You should never apply an input signal to an op-amp unless both supply voltages are present.

Figure 1


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Figure 2

3. MATERIALS1 DMM

1 Dual-polarity variable dc power supply

1 Variable ac signal generator1 Dual-trace oscilloscope

1 A741 Op-amp (or equivalent)9 Resistors: 470 , 1 k , 10 k (3), 27 k , 39 k , 47 k , and 82 k1 1-k Potentiometer

4. USEFUL FORMULASi

f

CLR

RA =

(calculated)

in

outCL

V

VA = (measured)

(Note: ACLis used in place ofAvwhenever output-to-input feedback is used. The subscript CL isused to denote closed-loop voltage gain.)

5. PROCEDUREPart I. Operation

A. Construct the circuit shown in fig. 2.B. Apply power to the circuit. Adjust the signal generator for a 1-V PP output at a frequency of

500 Hz. Apply the input signal to the amplifier. Note: If you are using a function generatorwith dc offset controls, make sure that the offset is set at 0 V.

C. Set up your oscilloscope to measure the circuit input and output wave forms simultaneously.Draw these waveforms on the grid provided.


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D. Calculate the value ofACLfor the circuit.

ACL=

E. Measure and record the peak-to-peak input and output voltages.

Vin= Vpp Vout= Vpp

F. Using the values ofVinand Voutfrom step 5, calculate the value ofACLfor the circuit.

ACL=

G. Calculate the percent of error between the values obtained in steps 4 and 6 of the procedure.

% of error =

H. Below Table 1 contains a series of resistance values to be used in place ofRfin the circuit.

For each value ofRf, repeat steps 4 through 7. Record your measured and calculated values in

the appropriate spaces in the table.

TABLE 1

Table 1


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I. Increase the input level to 5 Vpp. Return Rf to 10 k . Connect a l0-k resistor as a load.Measure the voltage gain of the amplifier. Change RL to 1-k and then to 470 . For eachvalue, measure the voltage gain.

ACL= (RL= 10 k ) ACL = (RL=1 k )

ACL= (RL= 470 )

How did the changing load affect the amplifier voltage gain?

J. Now set the l-k potentiometer to its maximum setting and connect it as the load. Slowlydecrease the value ofRLuntil the amplifier voltage gain starts to decrease and the waveform

starts to distort or clip. Remove the potentiometer and measure and record this value.

RL=

Part II. Fault Symptoms

K. Remove Rf from the circuit. Observe the circuit output waveform and draw it on the gridprovided.

Note: Whenever you are directed to remove a component, a gap should be left where the com-ponent appeared in the circuit. Do not bridge the gap left by the missing component unlessdirected to do so.


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LAB IX

EXPERIMENT 4

NONINVERTING AMPLIFIERS

1. OBJECTIVE

To demonstrate the operation of the non-inverting amplifier.

To demonstrate the effects of resistor faults on the operation of the non-inverting amplifier.

1. DISCUSSIONThe non-inverting amplifier has many of the characteristics of the inverting amplifier. There are twoexceptions. As the name implies, the output of this amplifier is in phase with its input; that is, there isno 180

0voltage phase shift. Also, the non-inverting amplifier has significantly higher input

impedance than a comparable inverting amplifier. If you look at Fig. 1 below, you can see that theinput is connected directly to the non-inverting terminal of the op-amp. As a result, the circuit inputimpedance is equal to (or greater than) the input impedance of the op-amp itself. When compared todiscrete amplifier circuits like the emitter or source follower, the non-inverting amplifier shares someof their characteristics. It has high input impedance and low output impedance, and the input andoutput signals are in phase. The one major difference is that the non-inverting amplifier can have highvoltage gain, whereas the emitter and source followers are limited to voltage gains slightly less thanunity. In this exercise, you will investigate the basic operation of the non-inverting amplifier.

Figure 1

2. MATERIALS1 DMM

1 Dual-polarity variable dc power supply


1 Dual-trace oscilloscope

1 A7 41 Op-amp (or equivalent)

6 Resistors: 10 k (2), 27 k , 39 k , 47 k , and 82 k

4. USEFUL FORMULAS

1+=i

f

CLR

RA (calculated)


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in

out

CLV

VA = (measured)

5. PROCEDURE

Part I. Circuit Operation

A. Construct the circuit shown in Figure shown above.B. Adjust your signal generator output for a 1-Vpp output at a frequency of 500 Hz. Apply the

signal to the amplifier input. (Note: If you are using a function generator with dc offset

controls, make sure that the offset is set at 0 V.)C. Set your oscilloscope so that you can observe the circuit input and output signals

simultaneously. Draw the waveforms on the grid provided.

D. Measure and record the peak-to-peak input and output voltages of the amplifier.

Vin= Vpp Vout= VppE. Using the values ofVinand Voutmeasured in step 4, calculate the voltage gain of the amplifier.

ACL=

F. Calculate the voltage gain of the amplifier using the values ofRfandRi.ACL=

G. Calculate the percent of error between the values ofACLfound in steps 5 and 6.

% Of error =

H. For each of the values ofRfshown in Table 1, repeat steps 4 through 7.


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Table 1

Part II. Fault Symptoms

I. Remove the feedback resistor (Rf) from the circuit. Observe the resulting circuit output waveformand draw it on the grid provided.

Note: Whenever you are directed to remove a component, a gap should be left where the com-ponent appeared in the circuit. Do not bridge the gap left by the missing component unless

directed to do so.


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J. Return the feedback resistor to the circuit and remove the input resistor (Ri ). Draw the resultingcircuit output on the grid provided.


1) How would you account for the percent of error values obtained in steps 7 and 8 of the procedure?

2) How would you explain the output observed in step 9 of the procedure?

3) How would you explain the output observed in step 10 of the procedure?


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LAB X

EXPERIMENT 5

SUMMING AMPLIFIERS

1. OBJECTIVE To demonstrate the operation of a basic summing amplifier.

2. DISCUSSIONThe summing amplifier is an op-amp circuit that accepts several inputs and then produces an

output that is proportional to the sumof these inputs. The term proportionalis used becausethe circuit mayor may not have gain, and the circuit output is inverted. The inputs can be dc

or ac values. In this exercise, you will investigate a two-input summing amplifier using sine

wave inputs. It should be noted that op-amp 1 in Figure shown below, is used simply as a

buffer.


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Figure 1

3. MATERIALS1 DMM1 Dual-polarity variable dc power supply


1 Oscilloscope

2 A.741 Op-amps or equivalents

5 Resistors: 10 k (3), 22 k , and 33 k .

4. USEFUL FORMULA


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5. PROCEDURE

A. Construct the circuit shown above.

Note: In Figure above, the signal generator is supplying the two input signals to thesumming amplifier (op-amp 2). Op-amp 1 is used to provide isolation between the

summing amplifier inputsB. Apply power to the circuit. Adjust the signal generator for a 1-Vpk, 300-Hz output. Using

the equation given above, predict the output from the summing amplifier when V1= V2=1 Vpk.

Vout=-------------------C. Using the equation given above, predict the output from the summing amplifier when V1

= V2= 1 Vpk.

Vout=-------------------D. Measure and record the peak output voltage.

Vout=-------------------E. ReplaceR1 with the 22-k resistor. Using this value in the original equation, predict the

output from the summing amplifier when V1 = V2= 1 Vpk

Vout=---------------------F. Measure and record the peak output voltage.

Vout=--------------------G. Replace Rfwith the 33-k resistor and return R1 to its original value. Predict the output

voltage for the circuit with V1= V2= 1 VpkVout=---------------------

H. Measure and record the peak output voltage.Vout=---------------------

I. ReplaceRfwith the 22-k resistor. Predict the output voltage for the circuit withV1= V2= 1 Vpk

Vout=---------------------J. Measure and record the peak output voltage.

Vout=--------------------K. Predict the output voltage for each V1, V2 combination shown Table below.


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L. Set the signal generator so that its peak output voltage is equal to each V1, V2combinationshown above (Table). For each input combination, measure and record the peak output

voltage.


2. Calculate the percent of error between your predicted and measured values ofVoutin steps3 and 4 of the procedure.

% of error =-----------------------------------How would you account for this error?

2) Compare your measurements in steps 4 and 6 of the procedure. Based on the two values,

what effect does increasing the value of an input resistor have on the output from a

summing amplifier?

3) Compare your measurements in steps 4 and 8 of the procedure. Based on the two values,what effect does increasing the value of the feedback resistor have on the output from a

summing amplifier?

4) Discuss, in your own words, what you observed in this exercise.

lab manual ece lab1-ece2201- sem i 2008 2009

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