Project #3 AC Load Measurement

Objectives

The ultimate goal of the project is to take measurements of a concealed AC load.

Tools

• Lab Equipment
• Circuit Simulator
• Hantek 3-in-1 Digital Equipment
• Powered Breadboard

Assessment

The overall weighted grading scheme is as follows:

Table 1     Overall Weighted Grading Scheme

I. The Challenge

Figure 1     AC Load Connection

Figure 1 shows the schematic of the circuit considered in this project. The circuit of interest contains an AC load denoted by Z_L, which is connected between nodes A and B.

At the start of a lab session, each group will be given an AC load that contains randomly chosen element types and values. With the AC load concealed in a box, your group is tasked with the challenge to achieve the following two objectives by the end of your lab session.

• Determine the impedance value of the given AC load at a specific given frequency.
• Determine the power factor value of the given AC load.

The grades earned in this first category of assessment depend highly on your success in achieving the two objectives described above. The weighted grading scheme is as follows:

Table 2     Weighted Grading Scheme for AC Load Measurement

In the process of working towards the above objectives, you MUST follow the following rules. Violation of any of the following rules will result in penalty detailed in Table 3 below.

• Rule #1: You are NOT allowed to unveil the AC load concealed in a box to help you achieve any of the two objectives described above.
• Rule #2: You are NOT allowed to use the resistance measuring function on any instrument including digital multimeter (DMM), LCR meter, etc. to measure directly the resistance of any circuit element.
• Rule #3: You are NOT allowed to use the capacitance measuring function on any instrument including digital multimeter (DMM), LCR meter, etc. to measure directly the capacitance of any circuit element.
• Rule #4: You are NOT allowed to use the inductance measuring function on any instrument including digital multimeter (DMM), LCR meter, etc. to measure directly the inductance of any circuit element.
• You are allowed to connect any circuit element externally to the AC load concealed in a box.

Table 3     Penalty for Rule Violation

IMPORTANT NOTES:

• WARNING: If you unveil the AC load concealed in a box to help you achieve any of the two objectives described above, you will earn a grade of zero for this specific project regardless of how much work you have completed. Penalty for the violation of Rule #1 will be strictly enforced.
• WARNING: Pay attention to all the rules and penalties described above. Please understand that the penalties are not created to destroy your grade; they are established for the sole purpose of ensuring fairness among all students who work on this project.
• Collaborations between any groups are strictly prohibited in this project.

TECHNICAL NOTES:

• WARNING: If you use a DC power supply, be mindful of the current setting on the equipment to avoid undesirable incident.
• Frequency response higher than 500 kHz will not be considered in this project.

II. Demo

Perform the following tasks.

• Provide both impedance and power factor values you have predicted for the given AC load to your Lab TA.
• Demonstrate to your Lab TA how you have arrived at your conclusions. Provide detailed explanations and reasonings on how you have obtained the results during your demo.
• Record down your results for the writing of your report.

The weighted grading scheme for Demo is as follows:

Table 4     Weighted Grading Scheme for Demo

IMPORTANT NOTES:

• All project demonstrations must be performed during a lab session. No project demonstration can be performed outside lab session.
• All groups will be given only ONE lab session to demonstrate the accomplishment of the objectives described above.
• HEADS UP: It is impossible to develop a working plan in a 2-hour lab session. To prepare fully for your project execution and demonstration, you are highly encouraged to perform circuit simulations and experiments at home so that you can figure out a plan for your project. To perform experiments outside of the laboratory, you can loan out a Hantek 3-in-1 digital equipment and a powered breadboard. You can also acquire circuit components from the laboratory, and they are not required to be returned.
• SUGGESTION: You are strongly encouraged to complete the following tasks prior to your lab session.
  • Establish an experimental plan to measure the impedance of a concealed AC load.
  • Figure out how to determine the power factor of an AC load.

III. Report

Document all your analysis, results and findings in a report. The content of your report should include, but not limited to, the following sections.

• Objectives and Tasks – define and outline explicitly the objectives and tasks
• Dissection of Experimental Plan – present your plan in a detailed, part-by-part analysis
  – explain the reasonings behind your plan using circuit theory
  – provide detailed circuit analysis and calculation to justify your plan
• Experimental Results – present your experimental results with clarity
  – include oscilloscope figures, screenshots of DMM measurements, etc.
• Results Comparison – compare predicted impedance and power factor values with theoretical values
  – analyze failure or success using circuit theory
– explain discrepancies pertaining to concepts
• Conclusions

The weighted grading scheme is as follows:

Table 5     Weighted Grading Scheme for Report