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Using multimeter, why do we hold its red lead to -ve and black lead to +ve terminal?

  1. Nov 14, 2011 #1
    What's the physics behind it?
     
  2. jcsd
  3. Nov 14, 2011 #2
    Re: Using multimeter, why do we hold its red lead to -ve and black lead to +ve termin

    Color coded so you know which is which.
     
  4. Nov 14, 2011 #3
    Re: Using multimeter, why do we hold its red lead to -ve and black lead to +ve termin

    Consistency, polarity convention.

    This way, you can compare to voltages and know whether they are both the same polarity or not, e.g., they are 100V and 150V, or 100V and -150V.
     
  5. Nov 14, 2011 #4
    Re: Using multimeter, why do we hold its red lead to -ve and black lead to +ve termin

    I think it's the other way round. We usually connect the red cable to the positive terminal and the black to the negative.
     
  6. Nov 14, 2011 #5

    davenn

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    Re: Using multimeter, why do we hold its red lead to -ve and black lead to +ve termin

    You beat me to it :) yes exactly. Im a bit suprised the first 2 responders didnt pick up on that one lol

    Dave
     
  7. Nov 15, 2011 #6

    Redbelly98

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    Re: Using multimeter, why do we hold its red lead to -ve and black lead to +ve termin

    I agree. And the only reason I can think of is that you would prefer to have a positive number for the meter reading. But it really isn't necessary; if you reverse the leads you just get -1 times the reading you would have gotten.
     
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