by Masood Ejaz - Valencia Collegefd.valenciacollege.edu/file/mejaz/EET 4158C - Linear... · 2020. 11. 25. · EET 4158C – Linear Integrated Circuits & Systems Electrical & Computer

Electrical & Computer Engineering Technology

EET 4158C – Linear integrated circuits & systems

Laboratory Experiments

by

Masood Ejaz

EET 4158C – Linear Integrated Circuits & Systems Electrical & Computer Engineering Technology

2 Valencia College

EXPERIMENT # 1

Inverting and Non-Inverting Amplifiers

Prelab: Calculate closed-loop gain, output voltage, and input resistance for both amplifiers

theoretically. Design both amplifiers in PSpice and perform all of the procedural steps. Op-amp

is present in the eval library.

Note: Save all of your waveforms from the oscilloscope for your lab report. Saved waveform

should show all of the relevant information.

Procedure:

Inverting Amplifier

1. Design the inverting amplifier as shown in figure 1. Op-amp is 741, Rf = 10K, and Rin =

1KUse ±15V to bias the Op-amp and choose vin = 1V (peak), 1KHz sinusoidal signal.

Make sure to connect both input and output terminals of the op-amp to both of the channels

of the oscilloscope. Observe the output and calculate the practical value of gain. Also,

confirm that the inverting relationship does exist between the input and output.

Figure 1: Inverting Amplifier

2. Measure the input resistance of the circuit by inserting a variable resistor between vin and Rin

and changing its value until the output voltage becomes half of what you measured in step 1.

Measure the value of the variable resistor. This is your approximate input resistance of the

circuit.

rin = ______________________________

3. Remove the resistance that you inserted in the last step and go back to the original circuit.

Increase the input voltage and observe its value when the output reaches to the saturation

limits. This is the maximum input voltage for the linear operation.

vin = ______________________; vout = ______________________


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Non-Inverting Amplifier

1. Design the non-inverting amplifier as shown in figure 2. Op-amp is 741, R2 = 10K, and R1

= 1KUse ±15V to bias the Op-amp and choose vin = 1V (peak), 1KHz sinusoidal signal.

Make sure to connect both input and output terminals of the op-amp to both of the channels

of the oscilloscope. Observe the output and calculate the practical value of gain. Also,

confirm that both input and output are in phase, i.e., output is not inverted.

Figure # 2: Non-inverting Amplifier

2. Increase the input voltage and observe its value when the output just reaches to the saturation

limit (the value just before the waveform starts getting slightly squarish, and if you further

increase the input voltage, it will become a square wave). This is the maximum input voltage

for linear operation.

vin = ______________________; vout = ______________________

Laboratory Report: Please follow the lab report rubric to get maximum points on your lab

report. Make sure to include circuits and waveforms in your lab report. Discussion should clearly

show your understanding about the subject matter.


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EXPERIMENT # 2

Linear Combination Circuits: Summing & Differential Amplifiers

Prelab: Write down output voltage expressions for both of the circuits.

Summing Amplifier: ____________________________________________________

Differential Amplifier: __________________________________________________

Design both amplifiers in PSpice and perform all of the procedural steps. Op-amp is present in

the eval library.

Note: (i) Save all of your waveforms from the oscilloscope for your lab report. Saved waveform

should show all of the relevant information. Make sure to change the format of the waveforms

from wav to bmp before you save them.(ii) Make sure to set the reference (GND) for both

channels of the oscilloscope right in the center. Once you set the proper reference then change

both channels to ‘DC’ to observe the properly shifted waveforms.

Procedure:

Summing Amplifier

1. Design the summing amplifier as shown in figure 1. Op-amp is 741. Use ±15V to bias the

Op-amp.

Figure 1: Op-Amp Two Input Summing Amplifier

2. Apply two convenient DC voltages to v1and v2 such that the magnitude of the combined sum

is less than or equal to 12V. Measure the output voltage and compare it with the theoretical

value.

vout (expected) = _________________________; vout (measured) = __________________;

OPAMP

+

-

OUT

R1

10k

R2

10k

R3

10k

0

v2

v1

vout


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3. Apply a negative DC voltage to one of the inputs and a 1KHz sinusoid to the other input.

Make sure that the combined sum of the magnitude of the DC voltage and peak value of the

sinusoid is less or equal to 12V. Observe the output voltage on the oscilloscope and compare

the expected maximum and minimum values of the output voltage with their expected values.


Differential Amplifier

4. Design the differential amplifier as shown in figure 2. Op-amp is 741.Use ±15V to bias the

Op-amp.

Figure 2: Closed-Loop Differential Amplifier

5. Apply two convenient DC voltages to v1and v2 such that the magnitude of the theoretical

output will be less than or equal to 12V. Measure the output voltage and compare it with the

theoretical value.


6. Apply a negative DC voltage to one of the inputs and a 1KHz sinusoid to the other input.

Make sure that the magnitude of the theoretical output values should be less or equal to 12V.

Observe the output voltage on the oscilloscope and compare the expected maximum and

minimum values of the output voltage with their expected values.


OPAMP

+

-

OUT

R1

1k

R2

1k

R3

2k

R4

2k

0

v2

v1

vout


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EXPERIMENT # 3

OPERATIONAL AMPLIFIER CLOSED-LOOP BANDWIDTH

Prelab: Write down the expression for the closed-loop voltage gain (as a function of frequency)

for the circuit and calculate the value of closed-loop bandwidth BCL for the circuit. Fill out other

theoretical information as required under the Procedure.

Closed-Loop Voltage Gain and BCL: ________________________________________________

Design the amplifier in PSpice and perform all of the procedural steps. Op-amp is present in the

eval library.

Note: Save all of your waveforms from the oscilloscope for your lab report. Saved waveform

should show all of the relevant information. Make sure to change the format of the waveforms

from wav to bmp before you save them.

Procedure:

1. Connect the inverting amplifier as shown in figure 1 with Rin = 1K and Rf= 10KUse

±15V for biasing voltages. Use vin to be a sinusoid with peak value to be 50mV. Choose a

very small frequency (close to DC) and measure the output voltage. Compare your measured

and expected values.

vout (expected) = _____________________; vout (measured) = _____________________

2. Increase the frequency to the calculated 3-db frequency (closed-loop bandwidth, BCL). Once

again, compare the expected and observed outputs. If you see any discrepancy between the

expected and measured outputs, explain the reason for that.

vout (expected) = _____________________; vout (measured) = _____________________

Figure 1: Inverting Amplifier


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3. Observe output voltage for a number of different frequency values to yield a graph between

vout vs. f for your lab report (Use MATLAB to create graph; instead of plot, use semilogx to

get a better picture of the response). Compare this plot with the PSpice simulation of the

circuit using AC sweep with the AC voltage of the sinusoidal source to be 50mV (Use

logarithmic AC sweep with start frequency to be 1Hz and a large end frequency to see the

complete frequency response).





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EXPERIMENT # 4

AC INTEGRATOR & LOW-FREQUENCY DIFFERENTIATOR

Prelab: Write down the frequency-domain expression for the output voltage of both circuits and

calculate the value of the 3-dB frequency.

Vout(j) and fb for the AC integrator: _______________________________________________

Vout(j) and fb for the low-frequency differentiator:___________________________________

Write down the time-domain expression for the output voltage of both circuits assuming that the

operating frequency is quite larger than the break frequency for the integrator circuit and quite

smaller for the differentiator circuit.

vo(t) for the AC integrator: ___________________________________________________

vo(t) for the low-frequency differentiator: ____________________________________________

Design both circuits in PSpice and perform all of the procedural steps. Make sure to run the

simulation until steady-state is reached. Op-amp is present in the eval library. Take your step-

size to be small (a good idea is to take it one-hundredth of the time period) so your waveform

doesn’t have sharp edges. Both square and triangular waveforms can be generated using

VPULSE under the SOURCE library, as explained below.

VPULSE

TD =

TF =PW =PER =

V1 =

TR =

V2 =

V1 Low Level Voltage

V2 High Level Voltage

TD Time delay before the first transition

TR Time it takes to go from low level to high level; Rise Time Square or rectangular waveform: Keep it as ‘0’ or a very small value (e.g. 1ps) if you see that there is a gradual rise instead of instantaneous. Triangular waveform: length of time it requires for the signal to rise from ‘V1’ to ‘V2’. For a symmetric triangular waveform, this will be half of the time period.

TF Time it takes to go from high level to low level; Fall Time Similar to the description of the rise time for rectangular and triangular waveforms.

PW Time span for which waveform is high during one period; Pulse Width Square waveform: half of the time period. Rectangular waveform: duty cycle*time period Triangular waveform: zero

PER Time period of waveform


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Note: Save all of your waveforms from the oscilloscope for your lab report that show all the

relevant information. Make sure to change the format of the waveforms from wav to bmp before

you save them. Also, keep oscilloscope channels on DC coupling once you set the reference

coupling (GND) to be in the center of the oscilloscope screen for both channels.

Procedure:

AC Integrator

1. Connect the AC Integrator as shown in figure 1 with Rin = 1K, Rf= 10Kand C =

1FUse ±15V for biasing voltages.

Figure 1: AC Integrator

2. Use vin to be a square wave with peak value of 4V (4V to -4V) and frequency of 1KHz. Make

sure that there is no DC offset for the square wave. Compare the output waveform shape and

maximum and minimum observed values against the expected ones. Make sure to support

your expected results with proper calculations.

vout shape and extreme values (expected) : ______________________________________

vout shape and extreme values (observed) : ______________________________________

3. Introduce a 1V DC offset to the input square wave. Hence, now input is a square wave with

maximum value of 5V and minimum value of -3V. Keep frequency to be the same (1KHz).

Compare the output waveform shape and maximum and minimum observed values against

the expected ones. Make sure to support your expected results with proper calculations.



4. Change vin to a triangular wave with peak value of 4V (4V to -4V) and frequency of 1KHz.

Make sure that there is no DC offset for the signal. Compare the output waveform shape and

maximum and minimum observed values against the expected ones. Make sure to support

your expected results with proper calculations.



C1

1u

Rf

10k

Rin

1k

U1

OPAMP

+

-

OUT

0

vinvout


11 Valencia College

5. Introduce a 1V DC offset to the input triangular wave. Hence, now input is a triangular wave

with maximum value of 5V and minimum value of -3V. Keep the frequency same (1KHz).

Compare the output waveform shape and maximum and minimum observed values against

the expected ones. Make sure to support your expected results with proper calculations.



Low-Frequency Differentiator

6. Connect the Low-Frequency Differentiator as shown in figure 2 with Rin = 1K, Rf=

10Kand C = 0.1FUse ±15V for biasing voltages.

Figure 2: Low-Frequency Differentiator

7. Let vin be a triangular wave with peak value of 4V (4V to -4V) and frequency of 100Hz.

Keep DC offset to be zero. Compare the output waveform shape and maximum and

minimum observed values against the expected ones. Make sure to support your expected

results with proper calculations.



8. Now introduce a 1V DC offset to the triangular wave used in the previous step and repeat the

same process.



Rf

10k

Rin

1k

U1

OPAMP

+

-

OUT

0

vinvoutC1

0.1u


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EXPERIMENT # 5

Comparators

Prelab: Determine the threshold voltage for both non-inverting and inverting Schmitt trigger

comparators.

Non-inverting: __________________________; Inverting: ____________________________

Simulate both circuits in PSpice and compare the output of each circuit against the expected

theoretical output. Op-Amp is in the eval library.

Procedure:

Note: Save all of your waveforms from the oscilloscope for your lab report.

1. Design the Non-inverting Schmitt Trigger as shown in figure 1 with R1 = 10K, Rf = 20K,

and ±15V for biasing voltages.

Figure 1: Non-Inverting Schmitt Trigger

2. Set input to be a triangular waveform with peak value of 10V (10V & -10V) and frequency

of 100Hz. Observe both input and output waveforms on an oscilloscope. Record values of the

input voltage at which output transitions take place. Compare them against the calculated

threshold voltages.

Input voltages for output transitions: __________________________________________

3. Design the Inverting Schmitt Trigger as shown in figure 2 with R1 = 10K, R2 = 20K, and

±15V for biasing voltages.


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4. Set input to be a triangular waveform with peak value of 10V (10V & -10V) and frequency

of 100Hz. Observe both input and output waveforms on an oscilloscope. Record values of the

input voltage at which output transitions take place. Compare them against the calculated

threshold voltages.

Figure 2: Inverting Schmitt Trigger

Input voltages for output transitions: __________________________________________


report. Make sure to include circuits and waveforms in your lab report. Include hysteresis loop to

discuss the working of comparators. Discussion should clearly show your understanding about

the subject matter.


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EXPERIMENT # 6

555 Timer Astable Multivibrator

Prelab: For the 555 timer circuit shown in figure 1, calculate values for RA and RB for the

frequency of the output to be 1KHz with 60% duty cycle. Choose C = 10nF.

Equation to calculate RB = __________________________________________________

Value of RB = ____________________________________________________________

Equation to calculate RA = __________________________________________________

Value of RA = ____________________________________________________________

Design the circuit in PSpice and perform all of the procedural steps. Make sure to run the circuit

until steady-state is reached. 555 timer is present in the eval library.

Note: Save all of your waveforms from the oscilloscope for your lab report. Saved waveforms

should show all the relevant information. Make sure to change the format of the waveforms from

wav to bmp before you save them.

Procedure:

1. Design the circuit shown in figure 1 with the values that you calculated in the prelab. Also,

use a 10Kload at the output.

Figure 1: 555 Timer Astable Multivibrator


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2. Connect the output to an oscilloscope and measure the output frequency and duty cycle.

fout= __________________________; Duty Cycle = _______________________;

3. If your values for the frequency and duty cycle are quite different from the expected ones,

measure the exact values of your resistors and capacitor and calculate the output frequency

and duty cycle based on the calculated values. Compare your calculated results against your

observed values.

RA(measured) = ___________; RB (measured) = ____________; C(measured) = _________

f (expected) = _______________; Duty Cycle (expected) = ____________________



show your understanding about the working of circuit, important applications of 555 timer, and

discussion of your expected and practical results.


17 Valencia College

EXPERIMENT # 7

Low-Pass Butterworth Unity-Gain Active Filter

Prelab: For the normalized unity-gain four-pole low-pass Butterworth filter, as shown in figure

1, calculate values of different components to satisfy following conditions. Normalized cut-off

frequency for the filter is 1 rad/sec.

fc = 5KHz; C1(final) = C3(final) = 10nF

Stage 1: C2(final) = ________; R1(final) = R2(final) = __________; Rbias1(final) = __________

Stage 2: C4(final) = ________; R3(final) = R4(final) = __________; Rbias2(final) = __________

Design the circuit in PSpice and perform all of the procedural steps. To get the frequency

response, use AC Sweep. Use Op-Amp 741 from eval library.

Note: Save all of your waveforms from the oscilloscope for your lab report. Saved waveforms

should show all the relevant information. Make sure to change the format of the waveforms from

wav to bmp before you save them.

Procedure:

1. Design the circuit shown in figure 1 with the values that you calculated in the prelab. Use

biasing voltage to be ±15V. Input is a sinusoid with 1V peak voltage.

Figure 1: Four-Pole low-Pass Butterworth Untiy-Gain Filter with Normalized Values

U1

uA741

+3

-2

V+

7V

-4

OUT6

OS11

OS25

U2

uA741

+3

-2

V+

7V

-4

OUT6

OS11

OS25

C1

1.082F

C2

0.9241F

C3

2.613F

C4

0.3825F

R1

1

R2

1

R3

1

R4

1

Rbias1

2

Rbias2

2

0 0

voutvin


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2. Connect the output to an oscilloscope and measure its peak value at the expected cut-off

frequency (5KHz). If expected cut-off is not correct, observe the practical cut-off frequency

by changing the input frequency until the output goes down to 0.7071V (peak).

voat fc (expected) = ________________________; fc (practical) = ________________

3. Observe several values for the output at different frequencies to plot the frequency response

curve.




Documents

by Masood Ejaz - Valencia Collegefd.valenciacollege.edu/file/mejaz/EET 4158C - Linear... · 2020. 11. 25. · EET 4158C – Linear Integrated Circuits & Systems Electrical & Computer