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Thread: potential difference

  1. #1 potential difference 
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    why potential difference divide in series circuit
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  2. #2  
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    Quote Originally Posted by SALLAR View Post
    why potential difference divide in series circuit
    because and
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    This is potentially an interesting question. The current flow through the circuit is determined by dividing the applied voltage (potential) by the total resistance and will be constant in all parts of a series circuit. The voltage drop across any of the resistances in the circuit will be then determined by multiplying the current by that particular resistance.

    You could kind of think of it like if you had a water hose of a certain size and a certain water pressure and the hose had some kinks in it. The water pressure will be greatest across the worst kink in the hose as there is greater resistance to the water flow, but the water flow will be the same in all parts of the hose.
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    Quote Originally Posted by SALLAR View Post
    why potential difference divide in series circuit
    If you are talking about Kirchhoff's voltage "law," the reason is as given by x0x. In a conservative field, the net potential around any loop is zero. I don't know if you are yet familiar with vector calculus, but in the language of that branch of maths, we can derive Kirchhoff's voltage law from Maxwell's equations as follows:

    1) If there is no time-varying magnetic field, then the E-field will be curl-free (del X E = 0). That then allows us to define the E-field in terms of the gradient of a potential, V: E = -div(V).

    2) Substitute the second equation into the first: del X [-div(V)] = 0. This is actually trivially true; it's a vector-calculus identity.

    3) The potential V along a closed-path, in turn, is given by the line integral of the E-field. Another vector calculus identity equates the line integral to the surface integral of the curl. But we began with a curl-free E-field. So, that all implies that the line integral of the E-field around any closed path is zero. In discrete circuit terms, that means that the sum of the voltages around any loop must be zero. Hence, any applied voltage must equal (minus) the sum of the voltages across all series-connected elements driven by that applied voltage. That's Kirchhoff's voltage law.
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    I am starting to think that some people here are way over educated with little knowledge of how things actually work.

    Moderator note (just playing) = Mayflow you are way out of line for calling out people who can post stuff from science classes in places they are not warranted just because they want to look smart, which they do not do to your frame of reference.
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  6. #6  
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    Quote Originally Posted by mayflow View Post
    I am starting to think that some people here are way over educated with little knowledge of how things actually work.
    Since you are way under-educated, you lack the competence to make such determinations. From other posts, you can't even properly interpret Kirchhoff's laws within their limited domain of applicability, let alone identify what that domain is. I'm certain you have no idea what "curl-free E-field" implies physically; it is a part of how things actually work.
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  7. #7  
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    Quote Originally Posted by mayflow View Post
    What is this curl free thing about? I mean the guy was just asking about voltage drops in a series circuit. If you WANT TO SHOW OFF SOME SUPERIOR TEACHINGS YOU THINK YOU HAVE, try doing so as a decent human being, ok?
    By definition, anything you don't understand is apparently "superior teaching" and must be mocked. Be that as it may, rather than trying to learn from what you have identified as superior knowledge, you fear it. Worse, you wish to deny it to others. Your aversion to learning is already well documented in several threads (I'm certain that you still smugly wallow in ignorance of the fact that log-periodic antennas are dispersive; looking up the references to find the truth would risk finding out something new -- can't have that!). But keep your love of ignorance to yourself, Mayflow. Maybe, just maybe, there are those that choose enlightenment instead.

    You are ignorant of Maxwell's equations, without which we would not have the wireless technology we have. Without engineers and physicists understanding what "curl free" means, we wouldn't have been able to build the cyclotron, with which Lawrence was able to probe the constituents of matter.

    And before you mock the cyclotron, you should look it up first. It begat the synchrotron, and then successive generations of particle accelerators, leading to the LHC in CERN. If we had stayed with a "curl free" field, the cyclotron would not have been possible.

    You need to up your game, Mayflow. Stop fearing what you don't understand. Stop assuming that those with superior knowledge are "showing off."
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