EETQ 114 Lab 1 - Meters

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Centennial College *

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EETQ114

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Electrical Engineering

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Jan 9, 2024

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Page 1 of 5 Centennial College Electrical Engineering Technician / Technology EETQ-114 Electronics 1 and Instrumentation 1 Name: Student #: Section: Date: LAB #1 Meters Objectives: Reading and comparing digital and analog meters. Theory: The use of measuring equipment is essential, when we work with experiments in electricity, Originally, only analog meters were available, but now digital meters have become commonplace. Analog meters are characterized by the fact that they use a pointer and scale to indicate their value. There are different types of analog meter movements. One of the most common is the d’Arsonval movement, this type of movement is often referred to as a moving-coil meter. Three distinct steps should be followed when reading a meter. These steps are especially helpful for someone who has not had a great deal of experience reading a multimeter. The steps are: 1. Determine what the meter indicates. Is the meter set to read a value of DC voltage, DC current, AC voltage, AC current, or ohms? It is impossible to read a meter if you do not know what the meter is used to measure. 2. Determine the full-scale value of the meter. The advantage of a multimeter is that it can measure a wide range of values and quantities. After it has been determined what quantity the meter is set to measure, it must then be determined what the range of the meter is.

Page 2 of 5 There is a great deal of difference in reading when the meter is set to indicate a value of 600 volts full scale and when it is set for 30 volts full scale. 3. Read the meter. The last step is to determine what the meter is indicating. It may be necessary to determine the value of the hash marks on the meter face for the range for which the selector switch is set. If the meter in Fig 2 is set for 300 volts full scale, each hash mark has a value of 5 volts. If the full-scale value of the meter is 60 volts, however, each hash mark has a value of 1 volt. Digital multimeters have become increasingly popular in the past few years. The most apparent difference between digital and analog meters is that digital meters display their reading in discrete digits instead of with a pointer and scale. This experiment is designed to expose the student to the operational characteristic of the VOM (Volt-Ohm, Milliammeter) and the DMM (Digital Multi-Meter). Equipment: • VOM (Simpson 260-8) • Variable DC Power Supply (BK Precision 1672) • DMM (Keithley 2110) • Patch cords (with banana plugs) Procedure: 1. Turn all knobs on the power supply fully counterclockwise and check the power is OFF. Ensure the 2 push buttons (INDEP) in the center of the power supply are both in the UP position. Fig. 1

Page 3 of 5 2. Make sure that you understand how to read the analog meter, completing the exercise below, enter the reading indicated by the 5 numbered needle positions and the ranges, also include units. Zero Adjustment Screw 60 VDC RANGE 1 2 3 4 5 300 VAC RANGE 1 ~42.5 V 2 105 V 3 155 V 4 ~212.5 V 5 265 V 12 VDC RANGE 1 2 3 4 5 60 VAC RANGE 1 2 3 4 5 3 VDC RANGE 1 2 3 4 5 120 mA DC RANGE 1 2 3 4 5 100 Ω RANGE 1 2 3 4 5 12 VAC RANGE 1 2 3 4 5 Ω Scale Volts and DC Amps Scale

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Page 4 of 5 3. With patch cords, connect the meters to the power supply as shown in Figure 1. 4. With the VOM set to the OFF position, check that the needle is pointing exactly to ZERO volts. If it is not, then slowly turn the ZERO ADJUSTMENT SCREW (first in one direction and then the other) until the needle is properly zeroed. Once this has been done, set the VOM to the 3-Volt DC range. (Note: at this range an input of 3V will result in full-scale deflection of the needle.) 5. Switch on the DMM and set it to the DC voltage range as shown in Figure 1 6. Switch on the DC power supply. Turn the left-hand CURRENT knob fully clockwise. 7. Slowly turn the voltage knob (the one on the left-hand side of the power supply) clockwise until the VOM shows an input of exactly .5 Volts. 8. Record the VOLTAGE READING indicated on the power supply's own meter into Data Table #1. 9. Read what is indicated on the DMM and record this information into Data Table #1 10. Continue to slowly turn the voltage knob (the one on the left-hand side of the power supply) clockwise until the VOM now shows an input of exactly 1.25 Volts. 11. Read both the power supply's meter and the DMM and record these measurements into Data Table #1. Repeat Steps 7 to 9 for voltage values of: 2 Volts and 2.75 Volts. 12. Adjust the VOM range switch to the 12-Volt DC range. Adjust the ZERO-ADJUSTMENT SCREW if necessary. 13. Continue to slowly turn the voltage knob (the one on the left-hand side of the power supply) clockwise until the VOM now shows an input of exactly 3.6 Volts. 14. Read both the power supply's meter and the DMM and record these measurements into Data Table #1. 15. Repeat Steps 13 & 14 for voltage values of: 5.1V, 8.8V & 11.3V. 16. Adjust the VOM range switch to the 60-Volt DC range. Adjust the ZERO-ADJUSTMENT SCREW if necessary. 17. Continue to slowly turn the voltage knob (the one on the left-hand side of the power supply) clockwise until the VOM now shows an input of exactly 19.5 Volts. 18. Read both the power supply's meter and the DMM and record these measurements into Data Table #1. 19. Repeat Steps 17 & 18 for voltage values of: 23V, 26.5V & 28V. 20. Calculate % Error for all the readings taken from the YOM and the power supply's display relative to the DMM (which is the most accurate & precise measurement device of the three.) Enter the results in Data Table # I. % 𝐸𝑟𝑟?𝑟 = | 𝑇𝑟?𝑒 𝑉𝑎??𝑒 − 𝐸𝑥?𝑒𝑟𝑖?𝑒??𝑎? 𝑉𝑎??𝑒 𝑇𝑟?𝑒 𝑉𝑎??𝑒 | × 100 Where : (1) “True value” is the reading taken from the DMM. (2) “Experimental value” is the reading taken from the VOM or power supply, respectively. 21. Calculate the average error values for the VOM and the power supply's display. 22. Write your own conclusions about this experiment.

Page 5 of 5 DATA TABLE #1: Test # VOM Readings (Volts) % Error Power Supply Display Readings (Volts) % Error DMM Measurements (Volts) 1 .500 2 1.25 3 2.00 4 2.75 5 3.6 6 5.1 7 8.8 8 11.3 9 19.5 10 23.0 11 26.5 12 28.0 AVG Error → AVE Error → Conclusion: State briefly, but clearly, what you have gained from this assignment. Lab Submission: - Please submit this lab report at the beginning of the next lab class for a full grade. Criteria Max Grade Materials, Tools and Equipment Set-up 1.5 Following Procedure 2 Data Collection and Analysis 2 Evaluation of Experiment, Review Questions 2 Conclusion 1.5 Spelling, Grammar, Sentence Structure 1 TOTAL

EETQ 114 Lab 1 - Meters

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