1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Current when resistors are connected in series.

  1. Mar 1, 2013 #1
    So, I was studying about electricity and I came to the topic of connecting resistors(or resistances) in series or parallel...

    So the definition of resistors in series said that:
    Resistors are said to be connected in parallel if they are joined end to end and the same current flows through each resistor when a potential difference is applied across the combination.

    So if the definition of the resistance is obstruction to the flow of the electrons when during electron drift collide with the atoms.

    How can the strength of current remain same when the first resistor only, reduce it.

    There was a similar thread regarding this query, but I didn't understand it. So I am posting this question.
  2. jcsd
  3. Mar 1, 2013 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Yes, resistors in series have the same current flowing through them. (I assume that you mean "series" not "parallel".)

    Not sure what you mean. If you change the total resistance (while keeping the applied voltage constant), you'll get a different current.
  4. Mar 1, 2013 #3
    I am trying to understand why the current in resistors that are wired in series is the same and I meant that, resistance is supposed to reduce the current. So if the current is reduced after it passes through one resistor, let's say from 10A to 7A...how in the world will it be the same current in that subsequent resistor?
    Last edited: Mar 1, 2013
  5. Mar 1, 2013 #4


    Staff: Mentor

    Resistors do NOT reduce current!!!!

    Suppose that you had a component which had an input current, I, and an output current I-δ. That would mean that the component would gain a net charge of t δ. In a very short amount of time, it would become so strongly charged that it would explode!

    This does NOT happen. Resistors do not reduce current. The same amount of current that enters a resistor leaves the resistor.

    What resistors do is enforce a proportionality between current and resistance by Ohm's law, V=IR. This means that for any voltage across the resistor there is a corresponding current through the resistor. If you fix the voltage and vary the resistance than that proportionality means that for a larger resistance the current will be smaller. But it does not ever mean that the current entering the resistor is less than the current exiting.
    Last edited: Mar 1, 2013
  6. Mar 1, 2013 #5
    Thanks a lot, sir...
    Really cleared my doubt...
  7. Mar 1, 2013 #6


    Staff: Mentor

    You are welcome, glad to help!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook