Lab 2 Ohms Law And Resistor Color Coding 5vn2m

AES 301E – BASIC ELECTRICAL ENGINEERING LABORATORY EXERCISES Name: _________________________________________ _______ Yr. & Sec.: Lab. No.: 2 ___________

Course: ________

Date: ___________

Instructor: ____________________________

Exercise 2: OHM's Law and resistor color coding . OBJECTIVES: 1. To find the value of a resistor and its tolerance by color coding. 2. To measure the value of the resistor by Digital Multi-meter (DMM). 3. To Ohm’s law experimentally and to find the relationship between voltage, current, and resistance in a circuit. II. EQUIPMENT:    

DC Power supply Ten (10) Assorted Carbon – Composition Resistors between 1 Ω to 1 M Ω Digital Multimeter with test leads Connecting wires

III. PROCEDURES: PART 1: IDENTIFICATION OF RESISTOR COLOR CODES 1. Select five resistors to use in this lab activity. Use the provided table to record data, calculations, and observations. Use pencil only. Have your teacher check your progress at checkpoints #1 and #2. Hand in this sheet for evaluation when it is completed. 2. Look at each resistor and identify the 3 bands used to calculate resistance. List the colors in the table under resistance colors. Look at the fourth band and decide whether it is a 5% (Gold), 10% (Silver), or 20% (no fourth band color) tolerance resistor. Place the resistor tolerance in the table under tolerance. 3. Use the chart to calculate the resistance of each resistor according to the colors you have listed. Place the resistance calculations in the table under calculated resistance. Be sure to label all resistance values with the ohms symbol (). 4. Convert the calculated resistance of each resistor to Kilo-ohms or Mega-ohms, as necessary, and place in the table under converted calculation. If no conversion is necessary, copy the calculated resistance into the converted resistance space. Be sure to label all resistance values as , K, or M. * STOP for teacher check and teacher demonstration.* 5. Meter the resistance of each resistor. Place the readings in the table under metered resistance. Be sure to label all resistance values as , K, or M. AES 301 – BASIC ELECTRICAL ENGINEERING by: Engr. Ma. Kristina P. Borbon, MEECE

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6. Calculate the accuracy of each resistor using the formula on the back of this sheet. Place your calculations in the table under accuracy. 7. In the table under rating, state whether you would rate each resistor as good or bad. Resistor Lab Data Table Resistor Number

Resistance Colors Band 1 Band 2

Band 3

Calculated Resistance

Converted Resistance

Metered Resistance

Tolerance

Accuracy

Rating

1 2 3 4 5 6 7 8 9 10 Stop! Get your work Checked.

Stop! Get your work Checked.

Questions: 1. What is the value of resistor having colors red, red, yellow and gold?

2. What does “short circuit” mean?

3. What does “open circuit” mean? AES 301 – BASIC ELECTRICAL ENGINEERING by: Engr. Ma. Kristina P. Borbon, MEECE

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PART 2: VERIFICATION OF OHM’S LAW

1. Assemble on the bread-board the circuit shown in Figure 2.6 using the same voltage setting on the power supply and the same resistor as shown. 2. Set the multi-meter to measure dc current, make sure that the leads are correctly set for current measurement. 3. Measure the current flowing through the resistor. Does this value agree with the calculations v   i  R ? using Ohm's Law  4. Measure the current flowing through the resistor in the opposite direction. This is done by reversing the leads of the ammeter. Does this value agree with the calculations using Ohm's Law v   i  R ? 

5. Complete the following table. Draw a graph between the measured voltage and current for each value of resistance; and find out the approximate value of resistance through the graphs drawn. AES 301 – BASIC ELECTRICAL ENGINEERING by: Engr. Ma. Kristina P. Borbon, MEECE

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IV. CONCLUSION:

AES 301 – BASIC ELECTRICAL ENGINEERING by: Engr. Ma. Kristina P. Borbon, MEECE

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