Lab Project : RC Lowpass Filters

Seneca College
SES250 Electromagnatics
Due Date: Sunday, Aug 4, 11:59 PM

Purposes

• To understand simple capacitive low-pass filter circuit
• To understand how to write a lab report

Objectives

• Assemble electronic components onto a breadboard
• Measure the filtering of signals using a Digital Storage Oscilloscope (DSO)
• Document your processes and results in a lab report

Description

Using what you've learned from Lab 7 and Lab 8 about capacitive and low-pass filters, your task is to create a capacitive low-pass circuit (series RC circuit) to filter out a noisy signal.

Task

1. You may work in groups of up to 2 members.

2. Design a series RC circuit that will filter out noise above 2kHz but not signal below 2kHz (ie. the cutoff frequency should be within 10% of 2kHz). You can use any of the resistors and capacitors you have in your lab kit.

3. Apply a signal with a 3V DC offset with a 2kHz 1Vpp triangular (saw) wave to simulate noise to your circuit. Remember the function generator should be set to High-Z mode.

4. Using the DSO, demostrate that the 2kHz 1Vpp noise is reduced to at least 70.7% of the original level after passing through your circuit (ie. show the raw signal with noise and the filtered signal).

5. Document your procedure and result in a lab report.

Deliverables

1. A lab report of no more than 5 pages and less than 1000 words consisting of the following sections:

   1. Introduction of the problem being studied and any relevant background information regarding to low-pass filter. (max. 300 words)
   2. Methods and Materials describing your circuit, and the materials and steps you used to test your circuit. This section must consist of figures and photos of:
      • list of materials/components used
      • list of steps you've taken (ie. someone must be able to repeat what you've done)
      • circuit diagram
      • breadboard diagram
      • photos of your component setup on a breadboard
      • photos of your test using a function generator and DSO
   3. Results from testing of your circuit by showing photos or a descriptive sketch of what you see from the DSO and measurement of any relevant voltage or current readings
   4. Discussion of your finding and explain what you see from the result. How can you prove that the 1kHz noise is filtered to 70.7%? Also discussed the following if applicable:
      • Are there any unexpected results or errors?
      • If you suspect any errors, analyze them.
      • Explain your result with relevant theories.
   5. Conclusion of what you've done, what challenges you faced, and what you've learned.
   6. Reference to cite any resource you've used in your introduction, methods, or discussion section. (Not included in pages and word count)

2. The report must be in PDF format with the name and student number of all members.

Deadline and Late Submission

Submit the lab report on Blackboard by the submission deadline. Only one submission is required per group.

Any late submission will receive a 50% mark deduction within 24 hours after the deadline, no mark will be rewarded afterwards.

Marking Rubrics

Introduction

(10 marks) Did this section clearly explain all necessary concepts and theories to understand the problem?

	Yes	Somewhat	Minimal	No
Marks	10	7	5	0

Methods and Materials

(5 marks) Did this section list all materials/components used?

	Yes	Somewhat	No
Marks	5	3	0

(25 marks) Did this section list all steps that were taken with photos and figures (ie. someone must be able to repeat what you've done)

	Yes	Somewhat	Minimal	No
Marks	25	15	10	0

(5 marks) Did this section contain a diagram of the circuit?

	Yes	Somewhat	No
Marks	5	3	0

(5 marks) Did this section contain a diagram of the breadboard configuration?

	Yes	Somewhat	No
Marks	5	3	0

Results

(10 marks) Did this section display results from the testing by showing photos or descriptive sketches of what you see from the DSO and measurement of any relevant voltage or current readings without any bias discussion?

	Yes	Somewhat	Minimal	No
Marks	10	7	5	0

Discussion

(20 marks) Did this section clearly explain the result and finding by providing a good discussion of the test and prove?

	Yes	Somewhat	Minimal	No
Marks	20	14	10	0

Conclusion

(10 marks) Did this section provide a clear summary of what you've done, what challenges you faced, and what you've learned?

	Yes	Somewhat	Minimal	No
Marks	10	7	5	0

Reference

(10 marks) Was a proper citation given in a recognizable reference format such as IEEE or MLA?

	Yes	Somewhat	Minimal	No
Marks	10	7	5	0