# Discuss the factors that must be considered when selecting op amps for an interface between a sensor and a data converter.

Interface and Design

Directions: Please answer BOTH of the questions and respond to a minimum of two of your classmates.

Question A

Discuss the factors that must be considered when selecting op amps for an interface between a sensor and a data converter.

Question B

Discuss the process of acquiring the necessary information for op amp designs.

Interfacing a Transducer to an Analog-to-Digital Converter and Interfacing Digital-to-Analog Converters to Loads

Watch video Week 5 – Op Amp DAC Circuit (Right click, save as)

Design an 8-Bit DAC Circuit – Calculate the values for all resistors

Include calculations and schematic in a Word document entitled: “HW5_StudentID”, with your student id substituted in the file name. Show all work for full credit.

Upload file “HW5_StudentID”

Interfacing a Transducer to an Analog-to-Digital Converter and Interfacing Digital-to-Analog Converters to Loads

The purpose of this lab is to allow students to gain experience constructing Digital to Analog Converters in Multisim. Students will extend the concepts learned in the module and homework to build an 8-Bit DAC. Several binary inputs and the associated analog output values measured with a virtual digital multimeter will be captured in screenshots.

Watch the video Week 5 – Op Amp DAC Circuit

Determine the values of all the remaining seven resistors and fill in the table 1.

Table1:

Resistors Values

R1 1k ?

R2

R3

R4

R5

R6

R7

R8

Recall the binary to decimal conversion and fill the table below:

Bits Binary Input Decimal conversion

MSB

(S1) 1000 0000

S2

S3

S4

S5

S6

S7

LSB

(S8) 0000 0001

Construct an 8-bit binary weighted DAC in Multisim and measure the output voltage Vout using the multimeter and record the computed gain below.

Table2:

Bits Binary Input Vin Rn

(n = 1,2,3,4,5,6,7,8) RF Output Voltage (Vout) Voltage Gain (Av)

MSB

(S1) 1000 0000

S2

S3

S4

S5

S6

S7

LSB

(S8) 0000 0001

Take the screenshots of Vout measurements for the input/output combination for each of the above 8-bits.

Answer the following questions:

Determine the approximate value of RF which results in accurate digital to analog conversion.

Write the expression for Vout in terms of Vin, RF and R for each bit. Also, express Vout in terms of all 8 input voltages.

Starting from the least significant bit to the most significant bit, what is the effect of feedback resistance on the output voltage?

From your measurements, does increase in the digital value result in increase in analog value? Please explain.

Is the voltage gain of the op Amp different for each bit? Please explain why?

Create a new word document called “Lab5_StudentID.docx” with your GID substituted into the file name.

Verify all calculations from analysis and measurements from simulations. Save the results along with the table and paste the screen captures in the word document. Make sure to answer the questions.

Upload file “Lab5_StudentID” in Blackboard.

Week 6

Directions: Please answer BOTH of the questions and respond to a minimum of two of your classmates.

Question A

Discuss the concept of phase shift in oscillators and how it is controlled in oscillator circuits.

Question B

Discuss the Wien Bridge Oscillator circuit and why it is suited for audio applications

Oscillator Circuits

Read Chapter 11 section 3 in the text.

Read Op Amp Oscillator Circuits.pdf

Answer the following questions:

List the general requirements for oscillation

How does an RC combination affect the phase plot of an oscillator

For a Wien-bridge oscillator

Given R = 20Kohm and C = 10nF what is the frequency of oscillation?

Given a required frequency of oscillation of f = 3kHz and R = 5kohm, what should the value of C be?

Save all work in a Word document with the title: “HW6_StudentID”, with your student id substituted in the file name. Show all work for full credit.

Upload file “HW6_StudentID”

Oscillator Circuits LAB

The purpose of this lab is to learn to use MultiSIM to construct and simulate oscillator circuits. Two oscillator circuits will be constructed and the effect of feedback resistance will be investigated in order to produce oscillation. Students will be asked to extend the concepts presented in order to modify the given circuit to allow for a variable output frequency.

Watch the video Week 6 – Oscillator Circuit

Read the section 11.3 and construct the two oscillator circuits in Figure 11.3 from the textbook and simulate the circuits.

Use the Agilent oscilloscope to observe the oscillations and measure the frequency.

Analyze the oscillations of Op-Amp and Comparator circuit and compare the Op-Amp circuit with that of the Comparator circuit.

Capture the screenshots showing oscillating output waveforms for each of the circuits.

Answer the following questions:

What is the difference between Op-Amp circuit and Comparator circuit?

Discuss some of the issues with this Op-Amp oscillations and explain the voltage swing and cause of potential failure of this circuit.

What makes the comparator circuit oscillate and more ideal for the applications?

Describe the operation of the comparator oscillator circuit and explain the difference in inverting and non-inverting waveforms of the comparator

What is the significance of using comparator circuit to achieve sinusoidal oscillations?

Create a new word document called “Lab6_StudentID.docx” with your GID substituted into the file name.

Verify all the measurements from simulation. Save the results and paste the screen captures in the word document. Make sure to answer the questions.

Upload file “Lab6_StudentID” in Blackboard.

Week 7

Op-Amp Noise Theory

Directions: Please answer BOTH of the questions and respond to a minimum of two of your classmates.

Question A

Discuss methods that analog signal designers can utilize to manage noise imposed on signals.

Question B

Discuss various ways in which to measure noise in MultiSIM and in physical circuits. Include a discussion of the various instruments that are useful in noise analysis

Op-Amp Noise Theory

Read Appendix B in the text.

Answer the following questions:

Calculate the signal to noise ratio given RMS Noise Voltage = 10mV and RMS Signal Voltage = 1V

Calculate ETotalRMS given e21RMS = 4V and e22RMS = 8V

Calculate SNR(dB) given a noise specification of 500.5nV

Calculate the noise specification given SNR(dB) = 150dB

Include all calculations in a Word document with the title: “HW7_StudentID”, with your student id substituted in the file name. Show all work for full credit.

Upload file “HW7_StudentID”

Op-Amp Noise Theory LAB

The purpose of this lab is to learn to use Multisim to analyze noise in op-amp circuits. Students will capture screenshots of the noise spectral density curves which will provide a visual relationship of the output noise voltage versus frequency.

Read the document on configuring a noise analysis in Multisim. Week 7 – Configuring Noise Analysis in Multisim.pdf

Following the instructions in pdf, construct the inverting Op-Amp circuit shown in figure 1.

Run the simulation to measure the gain of the Op-Amp and record the values of R1 and R2 and the measured gain in the table below. (Use 5% tolerance for R1 and R2)

Voltage gain (Av) R1 (5% tolerance) R2 (5% tolerance) Measured Voltage gain (Av)

1 1K?

5 1K?

10 1K?

12 1K?

For the gain of 5 in the table above, run the noise analysis to obtain the results for noise voltage for R1 and R2. (Note: You need to run this noise analysis for the circuit with the gain of 5 only)

Plot the noise spectrum density curve across frequency range of 100 Hz to 1 GHz. (Note: If your Multisim version does not support this option then try to download the trial version of Multisim Power Pro edition from NI website).

Answer the following questions:

Does the measured gain values match the given values? If not, explain why they are different?

From the noise spectral density curve, explain the effect of increasing the frequency on the noise voltage.

Is the voltage gain of the Op-Amp dependent on frequency? Please explain.

Create a new word document called “Lab7_StudentID.docx” with your GID substituted into the file name.

Verify all calculations from analysis and measurements from simulations. Save the results along with the table and paste the screen captures in the word document. Make sure to answer the questions.

Upload file “Lab7_StudentID” in Blackboard.

Week 8

Inductors and Operations

Directions: Please answer BOTH of the questions and respond to a minimum of two of your classmates.

Question A

Discuss some limitations of utilizing op amps to simulate inductors. Include some reasons why op amps are ideal for the construction of graphic equalizers.

Question B

Discuss one of the miscellaneous applications from the chapter that you were able to confirm its operation in MultiSIM. Describe how you went about confirming the operation.

Op-Amp Circuit Collection

Read Appendix D

Answer the following questions:

For a simulated inductor application, to yield L = 50mH, R1 = 2kohm, and C1 = 100uF, determine required value of R2.

For a constant current generator, with a saturation voltage = 15V and a current reference of 18mA, calculate RLmin.

For a precision rectifier application, given EIRMS = 5V, determine EOpeak.

For an AC to DC converter, given EIPeak = 6V, determine EI.

Include all calculations in a Word document with the title: “HW8_StudentID”, with your student id substituted in the file name. Show all work for full credit.

Upload file “HW8_StudentID”

Op-Amp Circuit Collection LAB

The purpose of this lab is to allow students with the opportunity to pull from all of the concepts presented in the course and be able to construct a circuit for a real time industry application. This lab will showcase all that was learned in the previous labs and allow for students to gain a greater appreciation of the important role that analog integrated circuits play in modern electronics.

Read the section D.10 Curve Fitting Filters from the Appendix D from the textbook (Op Amps for Everyone Fourth Edition).

Review the curve fitting equalization application discussed in this section (RIAA – Recording Industry Association of America).

Design the equalization preamplifier in Figure D.12 by understanding the circuit design requirements on page 269.

Perform AC Analysis to plot the response of the preamplifier. Take the Screenshots of the response and show the approximation of RIAA equalization curve.

Answer the following questions:

Describe the operations of this preamplifier circuit and explain how these preamplifier circuits work with single-supply circuits in limiting low frequency resonating components from the signal?

Discuss what parameters can independently adjusted to enhance the quality of sound.

Discuss the advantages of using this equalization preamplifier for sound reproduction.

Create a new word document called “Lab8_StudentID.docx” with your GID substituted into the file name.

Verify all the measurements from the simulation. Save the results and paste the screen captures in the word document. Make sure to answer the questions.

Upload file “Lab8_StudentID” in Blackboard.

Final

This item covers Weeks 5-8. Scan, handwrite answers and upload solutions. Show all required calculations for full credit.

Design a 16-Bit DAC Circuit

Calculate the values for all resistors

Include calculations and schematic

Capture a screenshot of several input/output settings from the 16-Bit DAC Circuit

For a Wien-bridge oscillator

Given R = 50Kohm and C = 100nF what is the frequency of oscillation?

Given a required frequency of oscillation of f = 10kHz and R = 8kohm, what should the value of C be?

Calculate the signal to noise ratio given RMS Noise Voltage = 20mV and RMS Signal Voltage = 2.5V

Calculate ETotalRMS given e21RMS = 5V and e22RMS = 7V

Calculate SNR(dB) given a noise specification of 680nV

Calculate the noise specification given SNR(dB) = 350dB

For a simulated inductor application, to yield L = 75mH, R1 = 3kohm, and C1 = 200uF, determine required value of R2.

For a constant current generator, with a saturation voltage = 20V and a current reference of 30mA, calculate RLmin.

For a precision rectifier application, given EIRMS = 5V, determine EOpeak.

For an AC to DC converter, given EIPeak = 10V, determine EI.

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