Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Current Sign in Cirrcuits.

  1. Sep 13, 2008 #1
    1. The problem statement, all variables and given/known data
    There is a basic circuit set up with just a resistor and an ammeter. If you put an ammeter into the circuit and a negative current is measured what does that mean in terms of the low and high ports of the Ammeter (a digital multimeter in this case)

    3. The attempt at a solution

    I Know that there is a port that is usually at high potential (red +) and a low one (black -). If a negative current is measured, that means that the current is flowing into the low potential wire of the ammeter and coming out of the high potential wire (correct?). So if a negative current is measured, then if the current is initially going through the initially low potential wire, then that wire turns into the high potential wire because it is where the current is starting and then it is flowing into the now low potential (originally the high potential) wire.

    Now, that was my original thought process. But i could play the devils advocate and say this: Since that is just a measurement of reference, and the circuit wasnt changed, the current is still flowing in the same direction. So, there is no way the potential could have changed. A negative current would just show that when the leads are switched, it is just measuring it from a different reference, and the wires are still at low and high potential. To me this seems like a weak arguement and my original statement seems better. Any help is much appreciated!
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted