How to Apply the Loop Rule in Circuit Analysis

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The discussion centers on applying the loop rule in circuit analysis, particularly for circuits with multiple batteries and resistors. The loop rule states that the sum of the electromotive forces (emf) and voltage drops across resistors in a closed loop must equal zero. Participants express confusion about handling circuits with more than one battery and whether to treat them as a single source. The advice emphasizes using Kirchhoff's rules rather than simplifying the circuit into series and parallel components. Properly identifying currents in the circuit is also highlighted as an essential step for accurate analysis.
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Homework Statement



Write the loop rule for each of the following circuits:
Untitled-1-1.jpg



Homework Equations


Depending on the loop:
-emf + IR1 + IR2 + ... + IRn = 0
V = IR
If in series: R1 + R2 + ... Rn = R
If in parallel: 1/R1 + 1/R2 + ... 1/Rn = 1/R

The Attempt at a Solution



I really don't know how to do these because we usually only had 1 battery. But here's my shot:

(A) Could you say that both batteries are in series and treat them as one battery, then say the R2 and R3 are in parallel?

(B) and (C) I don't have the slightest clue. For (B), I don't know if you can say that R1, R2, and R3 are in series with emf3 there, and (C) we've never had a battery in parallel (We either had 1 battery or 2 batteries in series).
 
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DeadFishFactory said:
Write the loop rule for each of the following circuits:

(A) Could you say that both batteries are in series and treat them as one battery, then say the R2 and R3 are in parallel? …

Hi DeadFishFactory! :wink:

"Loop rule" means that you only consider one loop at a time … that means everything is in one (series) circuit.

Forget the series and parallel rules … only apply Kirchhoff's rules …

voltage gain across each battery is the voltage (obviously! :rolleyes:), and voltage drop across each resistor is I times R, and for each loop t all has to add to zero …

what do you get? :smile:

(and don't forget to draw the currents in … I1 I2 I3 etc)
 
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