Equivalent Resistance: To Include or Not to Include r5 and r6?

AI Thread Summary
The discussion revolves around determining whether to include resistances r5 and r6 when calculating the equivalent resistance between points a and b. It is suggested that since r5 and r6 are in open circuits, no current flows through them, meaning they should not be included in the calculations. The equivalent resistance calculated without r5 and r6 is 1.6 ohms. The importance of having a closed circuit for current flow is emphasized, indicating that without connections, these resistances do not contribute to the overall resistance. Thus, the consensus is that r5 and r6 can be excluded from the equivalent resistance calculation.
sniderman
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Homework Statement


Trying to find equivalent resistance between points a and b.Dont know whether to include resistances r5 and r6.

Thanks


Homework Equations





The Attempt at a Solution


Im not sure what to do with the resistances r5 and r6in the open circuits are they apart of the calculations? i think they are not because nothing should be flowing threw them.
without them i got 1.6 ohms for a equivalent resistance
 

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sniderman said:

Homework Statement


Trying to find equivalent resistance between points a and b.Dont know whether to include resistances r5 and r6.

Thanks


Homework Equations





The Attempt at a Solution


Im not sure what to do with the resistances r5 and r6in the open circuits are they apart of the calculations? i think they are not because nothing should be flowing threw them.
without them i got 1.6 ohms for a equivalent resistance

Welcome to the PF.

Imagine connecting a resistance meter (DVM) between points a and b. That will put a voltage across those 2 points, which will cause currents to flow in some of the resistors. If points c and d are floating during this measurement, will there be any currents through R5 and R6?
 
i want to say that there is no current through those wires, because their not connected to anything making them open circuits?
 
If no current flows through a component then it will not contribute to the resistance.
 
ok, but is there current flowing in r5 and r6
 
sniderman said:
ok, but is there current flowing in r5 and r6

Where would it flow to? You need a CIRCUIT (closed path) for current to flow.
 
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