Kirchhoff's voltage law problem: Batteries, switches, resistors

  • Thread starter kenok1216
  • Start date
  • #1
58
1

Homework Statement


擷取.PNG

for S1,S2,S3,S4 are all closed at the long time
find the current in each resistor

Homework Equations




The Attempt at a Solution


why I3 is not = i2?
the solution of this question is
24-28I1-I212-12=0
7I1-32=3-----(1)

12-12I2-163=0
3I2+43=3 ---(2)

I1+I2-I3=0---(3)

I1=0.492 I2=0.148 I3=0.639[/B]
why there are 3 current in 2loop and I2 is not =I3 and why at the top loop
the equation is not 24-28I1-[I1-I2]12-12=0???
 

Answers and Replies

  • #2
andrewkirk
Science Advisor
Homework Helper
Insights Author
Gold Member
3,886
1,454
why there are 3 current in 2loop
Currents are measured through wires, not in loops. There are three wires through which different currents are flowing (ignoring the wires with negligible resistance), so we measure three currents.
and I2 is not =I3
Because the currents going out rightwards from the top two wires return leftwards in the third wire.
 
  • #3
58
1
Currents are measured through wires, not in loops. There are three wires through which different currents are flowing (ignoring the wires with negligible resistance), so we measure three currents.
Because the currents going out rightwards from the top two wires return leftwards in the third wire.
Thank
 

Related Threads on Kirchhoff's voltage law problem: Batteries, switches, resistors

  • Last Post
Replies
9
Views
5K
Replies
3
Views
128
Replies
4
Views
749
Replies
9
Views
3K
Replies
8
Views
945
Replies
8
Views
191
Replies
1
Views
3K
Top