Capitol College

Spring Semester 2000

Circuit Theory EE - 159

Lab Experiment: #1

Trainer and Multimeter Fundamentals

Andy Buettner

Instructor: Mrs. Thomas, Phd.

Due: February 2^nd, 2000

Received: ________________

• Objective

The objective of this lab is to instill a familiarity with the various components associated with taking electronic measurements. Primarily the volt - ohm meter (VOM), and the digital multi - meter (DMM).

• Equipment Used

1. EE - 159 lab kit # 1361

2. Radio Shack 14 value analog multimeter

3. ET 3600 Lab trainer

4. TI - 82 programmable graphing calculator

5. Simson analog Volt - Ohm Multimeter # 1336

6. Fluke Digital Multimeter ser # 31101513

• Components Used

1. 10 Carbon - oxide 5% tolerance resistors ¼ watt.

2. 1K pot

• Procedure

1. Trainer

1. Familiarize with the equipment: VOM, DMM, ET - 3600

2. Zero all adjustors, disconnect all previous wiring, and ensure that the power switch is in the off position.

3. Ensure that the lab kit is plugged in.

4. Power the lab kit.

5. Review proper use of multimiters.

1. VOM Voltage measurements

1. Zero and Calibrate the VOM.

2. Connect test leads.

3. Turn on the VOM; set to 50V range.

4. Connect the VOM leads to the power source of the trainer.

5. Turn on the Trainer and adjust voltage regulator to about 5vdc.

6. Read value on VOM

7. Change VOM range from 50vdc to 10vdc.

8. Take voltage reading again.

9. Adjust trainer voltage output to about 2vdc

10. Change VOM range from 10vdc to 2.5vdc

11. Record maximum voltage range of VOM

12. Turn off all equipment.

1. DMM Voltage measurements

1. Connect leads to the DMM.

2. Turn DMM to 400V range

3. Turn trainer to 4V range

4. Change DMM range from 400Vdc to 40Vdc and record result.

5. Change DMM range from 40Vdc to 4Vdc and record result.

6. Change DMM range from 4Vdc to 400mVdc and record result.

7. Change DMM range from 400mVdc to 100Vdc and record result.

1. VOM Resistance measurements

1. Fixed resistors

   1. Randomly chose ten resistors

   2. Log them and record their estimated values.

   3. Zero and calibrate the VOM

   4. Record the actual resistance of each resistor

   5. Calculate actual error of each resistor.

2. Variable resistors

   1. Use the 1k pot.

   2. Turn adjuster to the left.

   3. Take reading between thermals 1,2; 1,3; 2,3

   4. Turn pot ¼ toward the right.

   5. Repeat step 3.

   6. Turn the pot an additional ¼ turn right.

   7. Repeat step 3

   8. Turn the pot fully to the right

   9. Repeat step 3

• Results

• Table 1: Voltage read with VOM

• Table 2: Voltage read with DMM

• Table 3: Fixed Resistance Measurements

• Table 4: Variable Resistor Measurements

• Table 5: Resistance Ranges

• Answers to Questions

1. What range would you use on the VOM to measure an expected voltage of 22V?

Always, when you have an expected voltage, use the lowest range that includes the expected value: 0Vdc to 50Vdc

1. What range on the DMM would you use to measure 50V?

Again, use the lowest range that contains the expected level: 0Vdc to 400Vdc

1. Explain the voltage change between using different ranges to measure the same voltage.

The difference in voltage readings between the different ranges was attributed to the fact that each range has a different level of accuracy. When the level of accuracy was changed, the displayed value changed as a result.

1. Explain how you can tell on a DMM if the range you are using is incorrect.

If the result displayed is indicated that it is out of logical range or the result is not displayed with accuracy, the range setting is incorrect.

1. How accurate were the resistors?

Very few resistors, (Only one of the tested ones) are exactly what their values read. Of the 10 tested, 2 were outside of the tolerance range, however, since the readings were taken with an analogue multimeter, the readings may not have been perfectly accurate.

1. Show how to correctly wire the given schematic:

The schematic and drawings are located on the attached sheets: section <1>

• Conclusion

Through this lab I utilized my skills at using a multimeter to obtain critical values of electronic components. I preferred to use my own equipment for the last part of this experiment as I feel that it would be in better condition, and able to give adequate results. Additionally I would not have to reserve additional lab time. Otherwise I used the school-supplied equipment. Overall, I felt that this lab was quite simple. Additionally, I would like to comment that the VOM needs to be re - calibrated at the range that it is set to each time that the resistance range is changed to ensure accurate results. Tabled results were calculated with self - written TI - Basic program.

• Attachments

1. Original Handout

2. Original Data sheets

3. Calculations worksheets

4. Misc.