EET-117 LAB 4 F21 DONE

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Centennial College *

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117

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Electrical Engineering

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Apr 3, 2024

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Centennial College ELECTRICAL ENGINEERING TECHNICIAN & TECHNOLOGY Course: EET-117 Name Student Number Date Lab #4 MEASUREMENT OF RESISTANCE Based on Experiments in Basic Circuits by David Buchla Objectives: 1 Determine the listed value of a resistor using the resistor color code. 2. Use the DMM (or VOM) to measure the value of a resistor. 3. Determine the percent difference between the measured and listed values of a resistor. 4. Measure the resistance of a potentiometer and explain its operation. Required Instruments and Components: DMM (Digital Multi-meter) VOM Power supply Breadboard Alligator test leads (from the EET-117 labkit) Resistors: 6 assorted value resistors (from the EET-117 labkit) Potentiometer of any value (from the EET-117 labkit – example: when it is labeled “103” it is – 10x10 3 Ohm or 10 kOhm resistor)

Procedure 1. Orient the 6 resistors so that the color bands may be properly read from left-to-right on the breadboard as is shown in Figure 1. Make sure to leave a 5-hole spacing between the resistors to facilitate individual measurements. Fig. 1 2. Determine the color codes for the resistors and record them in the Table 1. 3. Before taking any resistance measurements with the DMM, always make sure to check the meter's ZERO ERROR. Our DMM (Keithley 2110) has auto-zero function automatically turned ON (p.81 of the manual). Over time and prolonged use, meters tend to go out of proper calibration and this will result in ZERO ERROR. In addition to above, the test leads (their resistance) may impact the correctness of the readings. Use NULL function to correct test lead’s resistance. When the null feature is enabled, the displayed reading is the difference between the measured input signal and the stored null (also called relative) value: Displayed reading = Measured input reading - Null value You can acquire the null (relative) value by measurement or by specifying the value. The null value is stored in volatile memory, which will be cleared when power to the instrument is cycled. Cancel out test-lead resistance that can result in inaccurate low-level resistance Measurements. The subsequent resistance measurement reading will exclude the test lead resistance. a. Turn the DMM ON b. Press 2 to select 2-wire ohm measurement. Ω c. Connect test leads to the instrument as shown below and connect them together (without a resistor). Fig. 2 d. Record the Resistance value shown on the display (test-lead resistance): __0.059_ohms_______________ e. Use NULL function to correct test lead’s resistance.

Fig. 3 4. With the Digital Multimeter (DMM) measure the actual ohmic value for each resistor and enter the results into Table #1. IMPORTANT: Make sure to wait for the meter's reading to stabilize before recording it into the table. 5. Use the % tolerance value to calculate the Minimum and Maximum possible resistance values for each resistor (Resistance Range) and determine (Yes or No) if the measured values falls within the tolerance range specified by the manufacturer. 6. Compute the percent difference between the measured and color-coded values using the equation: Table 1. Experimental data readings (columns 2-5 and 9 to be completed in the lab). 4 1 1 1 1 1 RESISTOR BEING TESTED BAND # 1 BAND # 2 BAND # 3 BAND # 4 Resistor value (Ω) Resistance range (calculated) DMM Measurement ( Ω ) % Dif. Is a tolerance within the range? (Y/N) Mark 1ST DIGIT 2ND DIGIT x10n Multiplier ±% Tolerance Min (Ω) Max ( Ω ) 1 2 3 4 5 6 7 8 9 10 11 1 Colour Brown Black Orang e Gold 10000 9999.9 5 10000.0 5 9.858 /5 Code # 1 0 10^3 +-5% 2 Colour Red Red Red Gold 2200 2199.9 5 2200.05 2.176 /5 Code # 2 2 10^2 +-5% 3 Colour Green Blue Red Gold 5600 5599.9 5 5600.05 5.545 /5 Code # 5 6 10^2 +-5% 4 Colour Orang e Orang e Red Gold 3300 3299.9 5 3300.05 3.253 /5 Code # 3 3 10^2 +-5% 5 Colour Red Violet Red Gold 2700 2699.9 5 2700.05 2.651 /5 Code # 2 7 10^2 +-5% 6 Colour Yellow Violet Red Gold 4700 4699.9 5 4700.05 4.638 /5 Code # 4 7 10^2 +-5% Are all the measured values for the resistors within the manufacturer's tolerance specifications? Indicate those that are out of tolerance. Marks: / 30

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