Difference between revisions of "Measure Resistance"
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| − | Resistance is the measure of difficulty electrons have in flowing through a particular object.<ref>http://www.physicsclassroom.com/class/circuits/Lesson-3/Resistance</ref> It is similar to the friction an object experiences when moving or being moved across a surface. Resistance is measured in ohms; 1 ohm is equal to 1 volt of electrical difference per 1 ampere of current.<ref>http://www.electricitycentral.com/articles/relationships.htm</ref> Resistance can be measured with an analog or digital multimeter or ohmmeter. | + | Resistance is the measure of difficulty electrons have in flowing through a particular object.<ref name="rf1">http://www.physicsclassroom.com/class/circuits/Lesson-3/Resistance</ref> It is similar to the friction an object experiences when moving or being moved across a surface. Resistance is measured in ohms; 1 ohm is equal to 1 volt of electrical difference per 1 ampere of current.<ref name="rf2">http://www.electricitycentral.com/articles/relationships.htm</ref> Resistance can be measured with an analog or digital multimeter or ohmmeter. |
[[Category:Physics]] | [[Category:Physics]] | ||
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== Steps == | == Steps == | ||
=== Measuring Resistance with a Digital Multimeter === | === Measuring Resistance with a Digital Multimeter === | ||
| − | #Choose the item whose resistance you wish to measure. For the most accurate measurement, test the resistance of a component individually. Remove the component from the circuit or test it before you install it. Testing the component while still in the circuit can cause inaccurate readings from other components.<ref>http://en-us.fluke.com/training/training-library/test-tools/digital-multimeters/how-to-measure-resistance.html</ref> | + | #Choose the item whose resistance you wish to measure. For the most accurate measurement, test the resistance of a component individually. Remove the component from the circuit or test it before you install it. Testing the component while still in the circuit can cause inaccurate readings from other components.<ref name="rf3">http://en-us.fluke.com/training/training-library/test-tools/digital-multimeters/how-to-measure-resistance.html</ref> |
| − | #* If you are testing a circuit or even just removing a component, be sure that all power to the circuit is turned off before proceeding.<ref | + | #* If you are testing a circuit or even just removing a component, be sure that all power to the circuit is turned off before proceeding.<ref name="rf3" /> |
| − | #Plug the test leads into the correct test sockets. On most multimeters, one test lead will be black and the other will be red. A multimeter often has multiple testing sockets, according to whether it is being used to test for resistance, voltage, or amperage (current). Usually the right sockets to test for resistance are labeled "COM" (for common) and one labeled with the Greek letter omega, Ω, which is the symbol for "ohm".<ref>http://www.electronics-radio.com/articles/test-methods/meters/multimeter-resistance-measurement.php</ref> | + | #Plug the test leads into the correct test sockets. On most multimeters, one test lead will be black and the other will be red. A multimeter often has multiple testing sockets, according to whether it is being used to test for resistance, voltage, or amperage (current). Usually the right sockets to test for resistance are labeled "COM" (for common) and one labeled with the Greek letter omega, Ω, which is the symbol for "ohm".<ref name="rf4">http://www.electronics-radio.com/articles/test-methods/meters/multimeter-resistance-measurement.php</ref> |
#* Plug the black lead into the socket labeled "COM" and the red lead into the socket labeled "ohm". | #* Plug the black lead into the socket labeled "COM" and the red lead into the socket labeled "ohm". | ||
#Turn on the multimeter and select the best testing range. The resistance of a component can range from ohms (1 ohm) to megaohms (1,000,000 ohms). In order to get an accurate reading of resistance you must set the multimeter to the proper range for your component. Some digital multimeters will automatically set the range for you, but others will need to be set manually. If you have a general idea of the range of resistance just set it to that range. If you’re unsure, you can determine the range through trial and error. | #Turn on the multimeter and select the best testing range. The resistance of a component can range from ohms (1 ohm) to megaohms (1,000,000 ohms). In order to get an accurate reading of resistance you must set the multimeter to the proper range for your component. Some digital multimeters will automatically set the range for you, but others will need to be set manually. If you have a general idea of the range of resistance just set it to that range. If you’re unsure, you can determine the range through trial and error. | ||
#* If you don’t know the range, start with the middle range setting, usually 20 kilo-ohms (kΩ). | #* If you don’t know the range, start with the middle range setting, usually 20 kilo-ohms (kΩ). | ||
#* Touch one lead to the end of your component and the other lead to the opposite end. | #* Touch one lead to the end of your component and the other lead to the opposite end. | ||
| − | #* The number on the screen will either be 0.00, OL, or the actual value of resistance.<ref>https://learn.sparkfun.com/tutorials/how-to-use-a-multimeter/measuring-resistance</ref> | + | #* The number on the screen will either be 0.00, OL, or the actual value of resistance.<ref name="rf5">https://learn.sparkfun.com/tutorials/how-to-use-a-multimeter/measuring-resistance</ref> |
#* If the value is zero, the range is set too high and needs to be lowered. | #* If the value is zero, the range is set too high and needs to be lowered. | ||
#* If the screen reads OL (overloaded) the range is set too low and needs to be increased to the next highest range. Test the component again with the new range setting. | #* If the screen reads OL (overloaded) the range is set too low and needs to be increased to the next highest range. Test the component again with the new range setting. | ||
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=== Measuring Resistance with an Analog Multimeter === | === Measuring Resistance with an Analog Multimeter === | ||
| − | #Choose the item whose resistance you wish to measure. For the most accurate measurement, test the resistance of a component individually. Remove the component from the circuit or test it before you install it. Testing the component while still in the circuit can cause inaccurate readings from other components.<ref | + | #Choose the item whose resistance you wish to measure. For the most accurate measurement, test the resistance of a component individually. Remove the component from the circuit or test it before you install it. Testing the component while still in the circuit can cause inaccurate readings from other components.<ref name="rf3" /> |
| − | #* If you are testing a circuit or even just removing a component, be sure that all power to the circuit is turned off before proceeding.<ref | + | #* If you are testing a circuit or even just removing a component, be sure that all power to the circuit is turned off before proceeding.<ref name="rf3" /> |
#Plug the test leads into the correct test sockets. On most multimeters, one test lead will be black and the other will be red. A multimeter often has multiple testing sockets, according to whether it is being used to test for resistance, voltage, or amperage (current). Usually the right sockets to test for resistance are labeled "COM" (for common) and one labeled with the Greek letter omega, which is the symbol for "ohm." | #Plug the test leads into the correct test sockets. On most multimeters, one test lead will be black and the other will be red. A multimeter often has multiple testing sockets, according to whether it is being used to test for resistance, voltage, or amperage (current). Usually the right sockets to test for resistance are labeled "COM" (for common) and one labeled with the Greek letter omega, which is the symbol for "ohm." | ||
#* Plug the black lead into the socket labeled "COM" and the red lead into the socket labeled "ohm". | #* Plug the black lead into the socket labeled "COM" and the red lead into the socket labeled "ohm". | ||
