Can someone help me find the equivalent resistance

In summary, the question asks to find the equivalent resistance of a circuit with R1 = 3 Ω, R2 = 2 Ω, R3 = 4 Ω, R4 = 1 Ω, R5 = 1 Ω, R6 = 2 Ω, and R7 = 2 Ω. The person tried reducing R4 and R3 in parallel, R6 and R5 in series, R1 and R2 in series, R12 and R7 in parallel, then R65 and R43 in series together, and finally R6543 in series with R127, but kept getting 2.07 ohms as the answer. They were advised to take R1
  • #1
Gonger
10
0
For this question I am pretty sure I am doing everything right but I just can't get the right answer. Diagram below. This is the question. Find the equivalent resistance of the circuit shown in the diagram, where R1 = 3 Ω, R2 = 2 Ω, R3 = 4 Ω, R4 = 1 Ω, R5 = 1 Ω, R6 = 2 Ω, and R7 = 2 Ω.

What I did was R4 and R3 in parallel, R6 and R5 in series, R1 and R2 in series, R12 and R7 in parallel, then R65 and R43 in series together, and finally R6543 in series with R127. I keep getting 2.07 ohms as my answer. If you can make out what I said can anyone help me?
Thanks
 

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  • #2
One problem I see with your calculations is you took R1 and R2 in series, but R2 is in series with R3//R4

R1 will be one of the last ones you can reduce
 
  • #3
OK I still can't get it

I have R3/R4 in parallel. Then I took that in series with R2. Then I took that in series with R6//R5. Then all of that in series with R7. And finally that in parallel with R1. Does all that sound right?
 
  • #4
Gonger said:
OK I still can't get it

I have R3/R4 in parallel. Then I took that in series with R2. Then I took that in series with R6//R5.

Are you sure about that?

Gonger said:
Then all of that in series with R7. And finally that in parallel with R1. Does all that sound right?

Are you sure about that?

Tip: Once you replace two resistors with an equivalent resistance, draw the circuit again with that replacement. That way, you will be able to see the relationships amongst the remaining resistors, instead of visualising it all in your head.
 

FAQ: Can someone help me find the equivalent resistance

What is equivalent resistance?

Equivalent resistance is the single resistance value that can replace a combination of resistors in a circuit and produce the same overall effect on the flow of electric current.

How do I calculate equivalent resistance?

To calculate equivalent resistance, you can use the following formula: 1/Req = 1/R1 + 1/R2 + 1/R3 + ... + 1/Rn, where Req is the equivalent resistance and R1, R2, R3, etc. are the individual resistances in the circuit. You can also use the series and parallel resistance formulas to solve for equivalent resistance in simpler circuits.

Why is equivalent resistance important?

Equivalent resistance is important because it allows us to simplify complex circuits and analyze them more easily. It also helps us understand how resistors in a circuit affect the flow of current and the overall behavior of the circuit.

Can equivalent resistance be higher or lower than the individual resistances in a circuit?

Yes, equivalent resistance can be either higher or lower than the individual resistances in a circuit. In series circuits, equivalent resistance is always higher than the individual resistances, while in parallel circuits, equivalent resistance is always lower than the individual resistances.

Are there any real-life applications for equivalent resistance?

Yes, equivalent resistance is used in many real-life applications, such as calculating the load on electric circuits, designing electronic devices, and determining the power and efficiency of electrical systems. It is also essential in fields such as electronics, engineering, and physics.

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