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Beginner's Question Regarding Voltage Division

  1. Jul 22, 2010 #1
    I'm pretty much a beginner trying to wrap my head around the concept of voltage division within a circuit. To help myself out, I've come up with the following circuit.

    [PLAIN]http://img401.imageshack.us/img401/801/voltagedivision.gif [Broken]

    I am having trouble determining the voltage between various points on the circuit.

    Starting with Ohms law, I know that the current in the circuit is 15V/15 ohms (or, 1A).

    Given the current, I can now determine the voltage between various points of the circuit.

    Between points 1 and 2, the amount of voltage is:

    V=1A x 5 ohms=5V

    Between points 1 and 3, the amount of voltage is:

    V=1A x (5 ohms + 5 ohms)
    V=1A x 10 ohms=10V

    Is this correct? Does the amount of voltage actually increase as your resistance increase? Sorry for sounding like a complete noob (which I am :) )

    Additionally, say I need to supply 10V to a device that happens to be connected at point 6 on my drawing. Where is the voltage measured from? Assuming I'm correct, if you measure from point 1 to point 6, then there is 10V being supplied. However, if you measure from point 2 to point 6, there is only 5V being supplied. Which figure is accurate?
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Jul 22, 2010 #2
    Your calculations seem correct.

    Current passing through a resistance make the voltage drop.

    For your last questions, I don't believe I follow you very well. Electric potential is always applied / measured between two points of a circuit. Therefore, it would be difficult to add 10V at point 6.

  4. Jul 22, 2010 #3
    In short... yes :)

    The basic answer is... yes :)

    Remember that voltage is always really a potential difference between two points; it's not absolutely defined at one point in a circuit.

    What is the ground point in your circuit? Your device that you're connecting must have a ground, or "another side" to the circuit, where the current flows back out.

    Also... remember that in practice voltage dividers aren't useful as power supply voltage regulators to power devices from a higher voltage supply than is appropriate... this is a common beginner mistake.
  5. Jul 22, 2010 #4


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    Here's a little interactive voltage divider you might like to play with.
    http://hyperphysics.phy-astr.gsu.edu/hbase/electric/voldiv.html" [Broken]
    Last edited by a moderator: May 4, 2017
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