simulate this circuit – Schematic created using CircuitLab

I am looking for help with what is probably a very basic question but I am new to electronics. The question I have is on a circuit and how to find various voltages, current, and resistance involving inductors.

In the question the circuit is using AC 120 V / 60 Hz and the first inductor (L1) is 100 mh it the splits in two with inductors L2 200 mh and L3 300 mh in series and they are parallel to L4 which is 400 mh and then it comes together back to the power source.

This is what I believe I have solved thus far:

  • The L Total is 322.222 mh
  • XLT is 121.475 Ohms
  • IT (Current Total) is 0.987858 A or 987.858 mA

I am asked then to figure out VL1, VL2, VL3, VL4, and IL2

VL1 I found by taking IT and multiplying it by XL1 and I got 37.241 V

I also got VL234 and got 82.759 V.

I just don't know how to split this up to get the individual voltages for VL2, VL3, and VL4.

Hope someone can help! Thanks.

  • 1
    \$\begingroup\$ it would if you provided a schematic of the circuit itself. \$\endgroup\$
    – kolosy
    Commented May 26, 2015 at 17:37
  • \$\begingroup\$ The cite has a built-in circuit schematic tool. It produces a more professional looking output. Hint: everything connected by an ideal wire is at the same potential. Use this to find how much voltage is across each branch. Then apply Kirchhoff's current law and Ohm's law to find how much current is in each branch. Once you know the current flowing through the top branch, you can use Kirchhoff's current law and Ohm's law again to find the voltage across L2 and L3 (like you did for L1). \$\endgroup\$ Commented May 26, 2015 at 18:07
  • \$\begingroup\$ Do you know how to handle resistors in series and parallel ? \$\endgroup\$
    – efox29
    Commented May 26, 2015 at 20:20

1 Answer 1


As L4 and L23 are in parallel their voltage is equal: thus VL234 = VL4. And similiarly VL234 = VL23.

Now you can calculate IL23 with XL23 and VL23. As they are in series the current through L2 and L3 is equal, so: IL23 = IL2.

Finally we need the voltages for VL2 and VL3: These can be easily computed using a voltage divider (https://en.wikipedia.org/wiki/Voltage_divider): VL2 = XL2*VL23/XL23. To compute VL3 you can now either use the same formula only with XL3 instead of XL2, or just subtract VL2 from VL23 (as voltage gets summed in series)


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