# How to apply Kirchhoff's rules in a circuit with Voltmeter? [closed]

I was trying to apply Kirchhoff's rules to find out the reading that will be shown by voltmeter. But then, I realized that the current coming out of the voltmeter arm will be zero (assuming infinite resistance) and am stuck. What should be the right approach in this case?

My (failed)Approach:

Simulation: I tried simulating it. Looks like the circuit is valid and Voltmeter would read 14V. This is the same result we get when we solve it through other methods. But KVL seems to not apply here or not giving this result.

Please note: this is not a homework question. I was genuinely curious with this special case (note the current flowing from + to - in the 12V). I saw questions around KVL in both Physics and EE stack sites. If this is more suitable in EE, could someone help in moving it please? I don’t have enough reps to do that myself.

• Are the two resistances those of separate resistors, i.e., not internal battery resistances? If so, the circuit should be drawn to show that.
– Ed V
Aug 12, 2022 at 20:18
• hi @EdV: Those are internal battery resistances. Aug 12, 2022 at 20:46
• Thanks! So the answer is the same as if the resistors were external.
– Ed V
Aug 12, 2022 at 21:57
• Hi Janaaaa. I agree with John's answer, but if you're determined to use Kirchoff what you could do is replace the voltmeter by a resistance R then use KVL to find the voltage in terms of R. Then take the limit of R ⟶ ∞ to get the voltage shown by an ideal voltmeter. Aug 14, 2022 at 4:37