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Internal resistance circuit problem

  • Thread starter Sarlizwx
  • Start date
  • #1
7
0

Homework Statement



In a circuit, two identical batteries with EMF of 22 V and internal resistance of 7 Ohm are placed in parallel to provide power to a load resistance of RL = 35 Ohms. What is the power transfered from the current to RL to heat the resistor?


Homework Equations


Is R(L) (Resistance load) mean the same thing as R(total)? I know EMF = Isys * Rsys as well.



The Attempt at a Solution



Only drew the diagram, labeled areas and put the RL = [1/R(1) + 1/R(2)] ^ -1I also know that Itot = I1 + I2. I'm assuming here that EMF of 22V is for each battery???
 

Answers and Replies

  • #2
261
2
The load resistance is the resistance of the resistor that is added to the circuit. In this case, the total resistance is not the same as the load resistance.
 
  • #3
7
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So RL = ((1/R1) + (1/R2))^-1 is an incorrect statement?
 
  • #4
GmL
13
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Your equation RL = ((1/R1) + (1/R2))^-1 only equates the total (internal) resistance of the batteries. The load resistance is a separate load (resistor) in the circuit which is in series with the two batteries. R(total)=(total internal resistance)+(load resistance RL).
 
  • #5
7
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Circuit/Power

Howdy,
If i've got the right circuit in mind, you could use Thevenin's Theorem to find the thevenin equivalent circuit then determine I and P.

Peace out.

Fez07
 
  • #6
7
0
Circuit/Power

Me again,
Forget my last comment. I was thinking of the wrong circuit. Use Superposition.
 
  • #7
7
0
Don't recognize either of those, Fez07
 
  • #8
7
0
Circuit/Power

Firstly, is this the circuit you have?
 

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