Find the voltage at point X on the circuit

AI Thread Summary
The discussion focuses on finding the voltage at point X in a circuit with given currents I1 and I2. The user calculated the equivalent resistance (Req) as 2.039 ohms and attempted to determine the voltage at point X using Kirchhoff's law. They initially arrived at two possible voltage values, 78.46V and 1.54V, but expressed uncertainty about their reasoning. Another participant suggested a simpler method by using the electromotive force (emf) of the 80V battery and the potential difference across the 2-ohm resistor. The conversation emphasizes the importance of understanding reference points in circuits for accurate voltage calculations.
mathman44
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Homework Statement



Here is the circuit:
Loop.jpg


I have found I1 to be -39.23A, I2 to be -25.38A, but I'm having difficulty reasoning how to find the voltage of point X.

The Attempt at a Solution



Here is what I tried. I calculated Req for the entire system by V/I = 2.039. Since there is already a 2 ohm resistor in the first loop, the system can be reduced to one loop with the 2 ohm resistor and a 0.039 resistor in place on the 3 ohm. Now "X" is between this 0.039 resistor and the 2 resistor, so using Kirchoff's law I found that X has a voltage of 78.46 or 1.54. Does this seem logical? I have to admit I'm grasping for straws here.
 
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The "earth" symbol at bottom left means that point in the circuit is taken as zero volts for reference purposes.
The voltage at X is simply, then, the pd between X and the Earth point.
One way you can find it is from the emf of the 80V battery and the pd across the 2 ohm resistor.
 
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Thanks, that sounds like a much simpler way of doing what I did!
 
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