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Ohm's Law or Ohmmeter?

  1. Mar 31, 2007 #1
    Are the resistance values of resistors which measured by ohmmeter and Ohm's law equal each other. Which of them are realiby than other? Please help me!
  2. jcsd
  3. Mar 31, 2007 #2


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    Measured values should agree with theory up to the measurement errors.
  4. Mar 31, 2007 #3


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    How does your ohmmeter determine a value of the resistance? How does an ohmmeter work?
  5. Mar 31, 2007 #4
    It must be the same within the measurement errors except for the fact that you measure at the boundary values. I mean if your ohmmeter has the measuring range from 1ohm to 10megaohm and you measure a resistor of about 1 ohm or appr.10 Mohm.
    It also depends on what kind of resistors you have. Some kinds of resistors have higher accuracy than others. There are resistors with 5%, 1% or 0.5% tolerance etc.
  6. Mar 31, 2007 #5
    In fact, I asked this question in general. So i have wanted you to give a general answer to me. There is no specific ohmmeter and there is no specific resistor. I asked only which one is more reliable? And thank all of you for your interests.
  7. Mar 31, 2007 #6


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    I would not consider one more "reliable" then the other.

    If you want to know what the actual circuit values are you must measure them, there are to many variables to rely solely on Ohm's law calculations.

    For the standard resistor, use the color code to find it's resistance. Now with a voltage measurement and Ohm's law you can determine the current. It is usually difficult to directly measure current since you must insert the ammeter into the circuit.

    Thus measurements and Ohm's law must be used together. They should not be seen as separate approaches.
  8. Mar 31, 2007 #7
    They are the same thing surfer. You have to measure volts to come up with a voltage to plug into the formula for ohms law. You have to measure the current also. An ohmeter uses all of the same components that voltmeters and current meters use. So you tell me, which is more accurate?
    Last edited: Mar 31, 2007
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