Exp 2: Resistor Color Code and Measurement
Objectives: After performing this lab experiment you will be able to:
1.
2.
3.
4.
determine the value of resistors from their color code.
measure resistors of different values.
measure a resistor using the various resistance ranges of an ohmmeter.
measure the resistance across each combination of two of the three terminals of a
potentiometer and to observe the resistance change as the potentiometer’s shaft is
rotated.
Perform all steps in the lab manual experiment.
Things to remember:
1. The unit of resistance is the ohm ( Ω ).
2. The body of a fixed resistor is color coded to specify its resistance value,
tolerance, and sometimes reliability.
3. Twelve colors are contained in the standard EIA color chart. These give the
values of the significant figures of resistance, the tolerance, and reliability.
4. Resistor color codes use either four bands (5% and 10% tolerance components)
or five bands (for precision components) to represent their values.
5. High-wattage wirewound resistors are not color coded, but have their resistance
and wattage ratings printed on their bodies.
6. Variable resistors are of two types, the rheostat and the potentiometer.
a. A rheostat is a two-terminal device whose resistance value may be varied
between the two terminals.
b. A potentiometer is a three-terminal device. The resistance between the two
end terminals is fixed. The resistance between the center terminal and either
end terminal can be varied.
7. An ohmmeter is used to measure resistance and continuity.
8. The scale of an “analog” ohmmeter is nonlinear.
Lab References:
1. Chapter 2, Resistance topic of Principles of Electric Circuits by Floyd
2. Nida Block 1 Lesson 5A: Resistors