Are these two resistors in Parallel?

  • Thread starter jwllorens
  • Start date
  • #1
2
0
Say I have a circuit that looks like this:

...._______
B___|_|_|_|___ A


The red and green lines are resistors.
The black lines are wires.

Assume a connection between any component line that is at a right angle to any other line, and a current source applied to points A and B.


My question is this: Are the two green resistors in parallel, and thus, can I reduce them to a single resistor using (Ra*Rb)/(Ra+Rb)?

If not, any suggestions on how to calculate the equivalent resistance of this entire circuit, between points A and B?
 

Answers and Replies

  • #2
berkeman
Mentor
58,013
8,071
Say I have a circuit that looks like this:

...._______
B___|_|_|_|___ A


The red and green lines are resistors.
The black lines are wires.

Assume a connection between any component line that is at a right angle to any other line, and a current source applied to points A and B.


My question is this: Are the two green resistors in parallel, and thus, can I reduce them to a single resistor using (Ra*Rb)/(Ra+Rb)?

If not, any suggestions on how to calculate the equivalent resistance of this entire circuit, between points A and B?
Welcome to the PF.

It's a little hard to read the diagram, but if there are just wires connecting the tops and bottoms of the two green resistors, then yes, they are in parallel.
 
  • #3
phinds
Science Advisor
Insights Author
Gold Member
2019 Award
16,343
6,541
Welcome to the PF.

It's a little hard to read the diagram, but if there are just wires connecting the tops and bottoms of the two green resistors, then yes, they are in parallel.
I had to magnify the page to really see the diagram but they ARE black (lines) so your explanation is correct.
 
  • #4
2
0
great, thank you. So the whole thing can be reduced to a diamond shaped circuit with a resistor in the middle, which becomes an irreducible circuit, at which point kirkoffs equations can be applied?
 
  • #5
berkeman
Mentor
58,013
8,071
great, thank you. So the whole thing can be reduced to a diamond shaped circuit with a resistor in the middle, which becomes an irreducible circuit, at which point kirkoffs equations can be applied?
There may be other simplifications, depending on the values of the resistors (like if there are symmetries). But in general yes, you would use KCL or some other technique to work on the circuit at that point.
 
  • #6
phinds
Science Advisor
Insights Author
Gold Member
2019 Award
16,343
6,541
great, thank you. So the whole thing can be reduced to a diamond shaped circuit with a resistor in the middle, which becomes an irreducible circuit, at which point kirkoffs equations can be applied?
Irreducible is a bit strong, since simple circuits like that have been done and have equations you can look up. Google "Delta-Y conversion" to see what I mean. You have a delta and want a Y and then you can go from there.

These conversion were done USING kirchoff analysis, so of course you CAN just do that.
 

Related Threads on Are these two resistors in Parallel?

  • Last Post
Replies
23
Views
4K
Replies
2
Views
2K
  • Last Post
Replies
9
Views
1K
Replies
11
Views
3K
  • Last Post
Replies
7
Views
5K
Replies
19
Views
6K
  • Last Post
Replies
1
Views
7K
  • Last Post
Replies
11
Views
2K
Replies
6
Views
7K
Replies
4
Views
5K
Top