Equivalent Resistance between A and D

AI Thread Summary
The discussion focuses on calculating the equivalent resistance between points A and D in a circuit with resistors. Participants suggest tracing current paths and simplifying the circuit diagram to identify parallel and series resistor configurations. They emphasize the importance of recognizing that points B and D are equivalent, and C is identical to A, which can simplify the analysis. Additionally, the conversation touches on how to approach the problem if capacitors were used instead of resistors, noting that the rules for combining capacitors differ from those for resistors. Understanding these concepts is crucial for accurately determining both equivalent resistance and capacitance in the circuit.
FamishedPluto7
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Homework Statement


I came across a problem and I was unable to understand how the effective resisitance of this circuit is to be calculated.
(Please refer to image uploaded)

Homework Equations

The Attempt at a Solution


Well I assumed that current tends to flow through wires without resistances preferably.
So I traces out a path such that the current flows from A to C without going theough B, then divides into 2 pathways, one containing 3ohm. The other, 1ohm.
Can somebody guide me with the correct equivalent resistance between A and D
Plus, let's say there were capacitors instead of the resistors, the values of their capacitances being same in magnitude as the resisitances in the image below. What would be the overall capacitance then?
 

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What you could try doing is simplifying the circuit.
Draw a diagram in which the points are placed separate enough, and draw the resistances in between.

Now pass current from A to C. You'll see that there will have to be current in more than just one path from A to D.

Hope this helps.
 
Qwertywerty said:
What you could try doing is simplifying the circuit.
Draw a diagram in which the points are placed separate enough, and draw the resistances in between.

Now pass current from A to C. You'll see that there will have to be current in more than just one path from A to D.

Hope this helps.
Thank you for your response, but I really have no clue as to how I can simplify this diagram more than this, if only I could do that, this would be easier to solve
 
FamishedPluto7 said:
Thank you for your response, but I really have no clue as to how I can simplify this diagram more than this, if only I could do that, this would be easier to solve
Mark points A, B, C and D, at the corners of say, a square. Now join the points appropriately using the wires/resistances.
 
FamishedPluto7 said:
Thank you for your response, but I really have no clue as to how I can simplify this diagram more than this, if only I could do that, this would be easier to solve
It's a bit like a game of snakes and ladders. Imagine that A has some positive voltage and you are a positive charge and you have to move from A to D while always dropping down in voltage. Use a different colour pencil and trace out all the alternative paths you can find that take you from A to D while descending the voltage gradient. Every alternative path here represents a resistance in parallel.

You'll recognize, too, that point B is really just point D with another name, and point C is electrically identical to A.
 
you can redraw this circuit to make it VERY simple.
hint: what is the definition of resistors in parallel and resistors is series.
 
FamishedPluto7 said:
Plus, let's say there were capacitors instead of the resistors, the values of their capacitances being same in magnitude as the resisitances in the image below. What would be the overall capacitance then?

The rules for
adding resistors in series : Rtotal = R1 + R2 + R3 + ...
adding resistors in parallel : Rtotal = 1 ÷ (1/R1 + 1/R2 + 1/R3 + ...)

so

how does this differ for
adding capacitors in parallel?
adding capacitors in series?
 
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