How Does Electric Current Flow Through a Resistor in a Parallel Battery Circuit?

  • Thread starter Lindsayyyy
  • Start date
  • Tags Tags
    Batteries
3 replies · 2K views · last reply
Lindsayyyy
Messages
215
Reaction score
0

Homework Statement



Two parallel connected batteries with internal electrical resistances R1 and R2 are connected with a resistance R of 5 ohm. Which electric current flows through R.

Homework Equations


U=I*R

U= voltage
R= resistance
I= electric current


The Attempt at a Solution



Hi everyone,

I have some trouble with this exercise as I'm fairly new to electrodynamics. The only idea I got so far was to sum the resistances as you do it when they are parallel connected:

1/R=1/R1+1/R2...

But then I have no idea how to go on. I could just calculate the R and insert it to the given formula I wrote down, but I'm far away from a specific answer to my question.
Can anyone give me some hints how I can solve this? Is there anything I'm missing?

Sorry for my bad english and for my lack of LaTex skill.

Thanks for your answers in advance.

Regards lindsayyyy
 
Does the attached figure match your circuit? Are the battery voltages, V1 and V2 equal?

Note that there are no parallel resistors in this circuit. There are two loops to solve using Kircchoff's voltage law, or if you prefer, a single node with three branches using the nodal method with branch currents.
 
Attachments
  • Circuit schematic with two dotted-outlined battery blocks side by side: Battery 1 contains R1 in series with V1, and Battery 2 contains R2 in series with V2, with their bottom wires joined; a 5Ω resistor sits on the right between the top and bottom wires.
    Fig6.gif
    1.9 KB · Views: 552
Thanks for your answer, your attached file looks like it should be. Sorry for forgetting a drawing of the problem.
The voltages are the same I guess, none are given at least.

edit: no parallel resistors? hm. Do I have to make a difference between inner resistors and the one with 5 ohm ? Am I not allowed to treach them as parallel ones?
 
Lindsayyyy said:
Thanks for your answer, your attached file looks like it should be. Sorry for forgetting a drawing of the problem.
The voltages are the same I guess, none are given at least.

edit: no parallel resistors? hm. Do I have to make a difference between inner resistors and the one with 5 ohm ? Am I not allowed to treach them as parallel ones?

They are not parallel: none of the resistors are connected to each other at both ends.

You can write branch voltage equations for the three branches that connect at node A using the currents as indicated, and solve the resulting equations for the desired current, I3.
 
Attachments
  • Circuit schematic with a node labelled Node A feeding three branches: R1 in series with battery V1 with current I1 upward, R2 in series with battery V2 with current I2 upward, and a 5 ohm resistor with current I3 to the right, all returning to a common ground.
    Fig7.gif
    1.6 KB · Views: 529