Calculate the voltmeter reading for this circuit with 2 sources and 2 resistors

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SUMMARY

The voltmeter reading for the circuit with two sources and two resistors is definitively calculated to be 12 V. The initial assumption of 8 V arises from a misunderstanding of the voltage drop across the resistors. The correct approach involves recognizing that the total voltage is the sum of the individual contributions from each source and the resistors, leading to the equation 10 V + 1 x 2 A = 12 V. This calculation is confirmed through the analysis of current flow and resistance values.

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  • Understanding of Ohm's Law (U=RI)
  • Basic knowledge of series and parallel resistor combinations
  • Familiarity with voltage sources in electrical circuits
  • Ability to analyze current flow in circuits
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Electrical engineering students, circuit designers, and anyone involved in analyzing or troubleshooting electrical circuits will benefit from this discussion.

songoku
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Homework Statement
Please see below
Relevant Equations
V = I.R
1685171477692.png


I find the current first, which is 2 A. Then the voltmeter reading would be 10 V - 1 x 2 = 8 V.

But the answer is 12 V.
I don't understand why it should be 10 + 1 x 2 = 12 V

Thanks
 
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I agree with your answer. It obviously cannot be more than 10V.
 
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Thank you very much haruspex
 
Yes, I agree, 8V is correct.
 
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Current returning to cell A = x
Current returning to cell B = y
Current entering the voltmeter = z

10- 1*x=0
4- 2*y = 0
z = y + x

X=10
Y=2
Z=12

U=RI

1/R=1/1+1/2
1/R=1,5
R=2/3

U = (2/3)*12 = 8

The reading is 8 Volts.
 
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Welcome to PF, @erpelkon

erpelkon said:
Current returning to cell A = x
Current returning to cell B = y
Current entering the voltmeter = z

10- 1*x=0
4- 2*y = 0
z = y + x

X=10
Y=2
Z=12

U=RI

1/R=1/1+1/2
1/R=1,5
R=2/3

U = (2/3)*12 = 8

The reading is 8 Volts.
It is okay to offer alternate solutions to old schoolwork threads where the OP has already solved the problem. Please just keep in mind that in active threads, the OP must do the bulk of the work. We cannot offer solutions to them until after they have solved their schoolwork problem. Thanks. :smile:
 
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