# How to find voltage across the resistor?

How to calculate the voltage V0 across the 8ohm resistor? Using mesh analysis I get an answer(120V) which is different from the correct answer.

Left loop, $$4I_1+V_1=120$$ Right loop, $$10I_2+2I_3+V_2=0$$ Outer loop, $$-120+4I_1+8I_3-8I_2=0$$

Solving I get, $$I_3=15A \text{ and }V_0=120V$$

• Is any data given about the transformer? Pleas edit the question to show the steps that you have followed.
– AJN
Nov 28, 2020 at 7:48
• Also, please use MathJax to format equations nicely. Make clear your effort up to point stuck and ask help to get unstuck, not expecting free homework service. Nov 28, 2020 at 11:09
• Which 8 ohm resistor? Nov 28, 2020 at 15:52
• @HotLicks The one which is connected to both primary and secondary side. And $V_0$ is the voltage across the resistor. Nov 29, 2020 at 12:01

So, draw an arrow going into left side dot and assign it a current variable. Then draw an arrow coming out of the other dot (or in to non-polarity dot side if easier) and assign it the same current variable, but scale it by $$\1/2\$$. Also, assign a voltage variable to one side, scale it and assign with appropriate polarity on the other side as well. Then you can write KVL and KCL equations to solve.
• See if my edit (added circuit with suggested variables) helps. The current up through the bottom right 8Ω resistor (from KCL) is $\frac{i_2}{2}+i_3$. Nov 28, 2020 at 14:24