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Homework Help: Basic Electrical Engineering

  1. Nov 8, 2007 #1
    1. The problem statement, all variables and given/known data

    I'm currently trying to find the total resistance of my resistors in my curcuit I have designed.

    2. Relevant equations

    I'm using the equation V = IR, where V = Potential difference in volts, I = Current in Amps and then there's R...

    It's a constant of sorts but I can't find it. Measured in ohms.

    3. The attempt at a solution

    I have a 2 Ohm resistor which is to reduce a 12V current. I just need to calculate the resistance from the resistor... but I can't work out the formula.

    Sorry if I seem a bit out of it, I haven't slept in days.
  2. jcsd
  3. Nov 8, 2007 #2


    User Avatar

    Staff: Mentor

    Get some sleep, and then please post more details about your question. We cannot help you figure out how to calculate the total resistance without seeing the circuit. Can you just use series and parallel combinations to simplify the resistor network? If not, then just write the KCL equations and solve for the node voltages, which will then get you to the total equivalent resistance.
  4. Nov 8, 2007 #3
    I'm just really trying to understand this equation:

    V = IR

    I have an example here where someone used it to find the total resistance of their resistor on their circuit.

    For example. A 12 volt battery connects to a 2 Ohm resistor.

    How would you calculate the total resistance made by that 2 ohm resistor? Here is what the example does.

    V = IR
    R = R1+R2+R3
    R = 5.5 + 2
    R = 7.5 Ohm

  5. Nov 8, 2007 #4
    Perhaps it's a virtual circuit.

  6. Nov 8, 2007 #5


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    Staff: Mentor

    Sorry, that makes no sense. If you have a 2 Ohm resistor, that is the total resistance. V=IR means that 12V=I*2Ohms, or I (the current) = 6A in your example.
  7. Nov 8, 2007 #6
    Sorry about this. I'll get some sleep and rethink the question.

    Thanks for the help anyway :D
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