Finding Currents in Complex Circuits - E1= 10V, E2= 6V

In summary, the conversation involves finding the current through each resistor in a circuit with two loops and a battery. The equations are set up by summing the voltages around the loop and conserving current at the junction. The superposition principle can also be used to calculate the currents separately and then add them together.
  • #1
SpaceTrekkie
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Homework Statement



I have to find the current through each resistor in this: http://i7.photobucket.com/albums/y297/SpaceTrekkie/Physics/Untitled.jpg circuit. All the resistors labeled R1 are 100ohms, the one labeled R2 is 1000 ohms and E1 = 10V E2= 6



The Attempt at a Solution



I figured out that there are two loops, one in the upper portion and one below, but I am not sure how to set up the equations because of the E2 (6V) battery is in the parallel portion.
I don't need the numerical answer, I just want to see how to set it up.
 
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  • #2
Well it's fine that the battery is there, in fact that is great because you automatically know the potential difference at the battery.
 
  • #3
But how does it affect the current comming into that parallel part when the current "splits" at the junction? Since it is flowing in the opposite direction.
 
  • #4
I don't understand what you are asking. Current can go through a battery. How is this any different than if you were to have one battery feeding into a parallel set of resistance?

You may be thinking about this too hard. For now simply get your equations by summing the voltages around the loop. Then find your currents. With more time and practice your questions will start to be answered.
 
  • #5
For the loop rule, just follow a line in a loop, if something falls onto the line include it in your equations

For the junction rule, the current has to be conserved. Current "flowing" in the direction opposite the battery could simple be interpreted as charging the battery. (Although, doesn't really make sense why one would want to charge a battery with a battery)
 
  • #6
Okay, thanks all, I think I get it now. Basically I go around the loop starting at the positve side of the 10V batter, and just go around like normal, calculating the potential drops at each resistor, then when I get to the 6V batter, since that is oriented the opposite way subtract off the 6V from whatever the potential is when it gets there, I don't have to do anything weird with the direction or currents or anything.
 
  • #7
Yes, that's correct.
 
  • #8
If I were you I would use superposition principle. Calculate the current from each source separetly (the other one is shorted) and then simply add the currents.
 

1. What is the total voltage in the circuit?

The total voltage in this circuit is 16 volts, as determined by adding the individual voltages E1 and E2.

2. How do I calculate the total resistance in a complex circuit?

To calculate the total resistance in a complex circuit, you will need to use the formula R = V/I, where R is resistance, V is voltage, and I is current. You will also need to consider the individual resistances of each component in the circuit and use the appropriate equations to calculate their effects on the total resistance.

3. Can I use Ohm's law to find the current in this circuit?

Yes, you can use Ohm's law (I = V/R) to find the current in this circuit. However, since this is a complex circuit with multiple components, you will need to use the equivalent resistance of the circuit to calculate the total current.

4. How do I find the current in a specific branch of the circuit?

To find the current in a specific branch of the circuit, you will first need to calculate the equivalent resistance of that branch. Then, you can use Ohm's law (I = V/R) to find the current in that branch.

5. What is the role of Kirchhoff's laws in finding currents in complex circuits?

Kirchhoff's laws play a crucial role in finding currents in complex circuits. Kirchhoff's current law (KCL) states that the sum of all currents entering a node in a circuit must equal the sum of all currents leaving that node. Kirchhoff's voltage law (KVL) states that the sum of all voltage drops in a closed loop must equal the sum of all voltage sources in that loop. These laws are used to set up and solve equations in order to find the currents flowing through different branches in a complex circuit.

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