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Electrical Circuits

  • 18-12-2012 3:24pm
    #1
    Fordie99
    Registered Users, Registered Users 2 Posts: 18 ✭


    Okay I haven't a clew about circuits and the measurements or calculations needed so I help. Here's the problem:

    unnamed-circuit

    In the circuit shown what are currents Over R1 and R2. Using Kirchoffs current law determine the current flowing through R3. How much voltage is dropped across the 2.2k resistor? how much voltage is Dropped across the 5k resistor? using kirchoffs voltage law determine the voltage drop across R2.
    Tagged:


Comments

  • #2
    clartharlear
    Registered Users, Registered Users 2 Posts: 489 ✭✭clartharlear


    I can't see any circuit.


  • #3
    BrianDug
    Registered Users, Registered Users 2 Posts: 163 ✭✭BrianDug


    How far have you gotten or what have you tried?

    A Little help to get you started:
    Resistance in series - RT = R1 + R2 + R3 ... RN
    Resistance in parallel - 1/RT = 1/R1 + 1R2 +1/R3 .... 1/RN

    V = I/R
    I = V/R
    R = V/I

    So we want to make the circuit into a series circuit first to find the total current in the circuit using ohms law I = V/R.

    We will need to first combine R2 & R3 as they are in parallel so 1/RT = 1/R2 + 1/R3 = 1/4k + 1/4k = 1/2k Now we must invert this to get our answer so its = 2/1 which is 2kohms.

    So now of we look at the circuit we have in series R1 + R2R3 + R4 = 5k + 2k + 2.2k = 9.2k ohms total resistance.

    By ohms law I = V/R so 18v/9.2K = 0.001956521 A = 1.95mA. So that tells us the total current flowing in the circuit.

    If you can get your head around that try use Kircoff laws to get your answers, just keep in mind the total current we have found. You can add up all your individual currents and they will equal the total current so you will know if you are correct or not.


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