# What is Equivalent resistance: Definition and 209 Discussions

Practical capacitors and inductors as used in electric circuits are not ideal components with only capacitance or inductance. However, they can be treated, to a very good degree of approximation, as being ideal capacitors and inductors in series with a resistance; this resistance is defined as the equivalent series resistance (ESR). If not otherwise specified, the ESR is always an AC resistance, which means it is measured at specified frequencies, 100 kHz for switched-mode power supply components, 120 Hz for linear power-supply components, and at its self-resonant frequency for general-application components. Additionally, audio components may report a "Q factor", incorporating ESR among other things, at 1000 Hz.

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1. ### Can I find a general solution to this circuit?

TL;DR Summary: I have to find an equivalent resistance of the circuit below, dependent on the amount of ##R_3## - resistors. Here is the circuit: I think there is no general solution. When I want to calculate it, I have to do...
2. ### Engineering Equivalent resistance of an envelope peak detector (RF CMOS)

Full problem: I don't normally think about circuits like these in terms of energy (Joules) so I was very much confused. What I did was find where the simplified expressions intercepts with each other to get the voltage. I scanned in my work although this text is a walk through of what I did...
3. ### Find the equivalent resistance of this 5-resistor circuit

I have a question about an exercise I don't understand, I don't want the solution, only the first element to begin. I have tried with kirchhoff law, but I failed. thanks
4. ### Grade 11 physics and equivalent resistance

i keep getting 45.3 ohms but the answer is 25.6 ohms

6. ### Calculate the equivalent resistance

R1 = 2 ohms ; R2 = 2 ohms; R3 = 1ohm First figure: I need to calculate the resistance between: a) A and C and b) A and B a) R1 and R3 are in series => R13 = R1 + R3 = 3 ohms R13 and R2 are in parallel => 1/Rp = 1/R13 + 1/R2 => Rp = 1.2 ohms b) Here, between A and B there is only R1 so the...
7. ### Equivalent resistance of a section of a graphite ring

I considered that the lengths of pi/4 and 3pi/4 would be in parallel: 1/R = 1/30 + 1/10 R = 7,5 ohm But the answer is 30 ohm. Where am I missing and how do I calculate the potential of the voltmeter.

21. ### Equivalent resistance with a capacitor

Homework Statement So I need to find the equivalent resistance for the following RC circuit to calculate the time constant, but I got stuck in terms of finding out the equivalent resistance. Homework Equations V = IR The Attempt at a Solution So the thing I am not sure on is how do you...
22. ### The equivalent resistance for the resistors in this circuit?

Homework Statement If the circuit of parallel and series resistors , is as follows , what's the equivalent resistance for the group? Homework Equations neglecting the battery internal resistance... irrelevant to the question. The Attempt at a Solution I tried to do the following R1=8+12=20...
23. ### I finding the Thevenin equivalent resistance

Homework Statement https://imgur.com/a/XD3Km4t I'm trying to find the thevenin equivalent resistance across the opened terminals. Homework Equations I know you short circuit the voltage source and do simple circuit analysis, however I'm getting confused in determining what resistors are...
24. ### Equivalent resistance between two points

Homework Statement Homework EquationsThe Attempt at a Solution From symmetry , C and D are at the same potential . So , resistance between them can be removed . This leaves us with three parallel branches between A and B i.e 45 Ω || 45 Ω || 15Ω . The net resistance will be 9 Ω . But this...
25. ### Equivalent resistance of a circuit

Homework Statement Consider the electric circuit shown in the figure. Assume that V = 13.7 V, R1 = R2 = R3 = R4 = R5 = 7.00 Ω. What is the equivalent resistance of the circuit? Homework Equations total voltage of a series circuit is the sum of the voltage of all the resistors total current of...
26. ### Equivalent resistance between two points on a circuit

Homework Statement Homework EquationsThe Attempt at a Solution [/B] The circuit is symmetric about AC and BD , but I am not sure how to use this to simplify the circuit . Could someone help me in solving this circuit using symmetry considerations .
27. ### Engineering Find the equivalent resistance of this circuit w/o Data?

Homework Statement Find the equivalent resistance of this circuit between points a and b https://imgur.com/a/LWcIC Homework Equations The Attempt at a Solution I am not sure how to complete this problem without any variables. I tried replacing the numbers with the variables which is what I...
28. ### Engineering Circuit diagram: find the equivalent resistance

Homework Statement problem in title:Homework Equations 1/Rtotal = 1/r1 + 1/r2...[/B]The Attempt at a Solution [/B] I can get it down to 4 resistors...but the one's I have circled I don't know how they behave. I just need a little kick in the right direction lol. Thank you in advance!
29. ### Calculating Resistance - Electrical Circuits & Networks

Hello! I've took a course about Electrical circuits and Networks at the university, and i found out a problem which is uploaded by my professor, and i think he made a mistake! this is the solution i think that the equivalent resistances are wrong (beside Rab), for example if you look at...
30. ### Equivalent resistance in a Wye formation

Homework Statement Find the Thévenin resistance for each of the circuits shown by zeroing the sources. Homework EquationsThe Attempt at a Solution I replaced the current source with an open circuit and I'm left with a wye formation but I don't know how to calculate the equivalent resistance
31. Y

### Equivalent Resistance of Figure

Homework Statement https://imgur.com/a/aVCeU Homework Equations (1/Req) = (1/Rv1) +(1/Rv2) Req = Rv1 + Rv2 The Attempt at a Solution I'm not sure which formula is the correct one to use.So.. I'm absolutely stuck. I tried downloading a bunch of circuit board simulators, but I couldn't find an...
32. ### Equivalent resistance of 2015 points

Homework Statement 2. Homework Equations [/B]The Attempt at a Solution so i was thinking i could take a look at small number of points and then generalize it but my method soon breaks down in the diagram i have denoted the resistance of the segment beside it if there is a bracket it means...
33. ### Calculate equivalent resistance

Homework Statement Homework EquationsThe Attempt at a Solution In the attached image the outer circular wire is represented as N . We have to find the equivalent resistance between O and N . Consider a battery of voltage V between O and N . From O there are six similar paths OA...
34. A

### Calculation of equivalent resistance

1. The Problem Statement Calculate the equivalent resistance between O and the circumference. Each wire has 24 ohm resistance and the circumference has zero resistance. 2. Homework Equations Not needed.3. Attempt at solution I tried to use symmetry to solve this problem. I understand that...
35. G

### A cube of side L=2 m is made of a cooper cable with 2mm^2

Homework Statement A cube of side L=2m is made of a cooper cable with 2mm^2 of cross section area. 1) Find the electric resistance of one side of the cube. 2) Find the equivalent resistance in between the points A and B.
36. ### Equivalent resistance between two points

Homework Statement Homework EquationsThe Attempt at a Solution [/B] All the resistors are connected in parallel across A and B .The equivalent resistance is 1/Req= (1/R) +(1/2R) + (1/6R) + (1/12R) + ... I tried to work with few terms and it seems the effective resistance tends to zero as...
37. ### Dumb question regarding short circuit test equivalent resistance

Hi, Silly little question about the transformer short circuit test. When I perform it with the secondary shorted and I get Req = Power / current2 is this Req = Rpri + Rsec? If I measured Rpri and Rsec with a multimeter? Thanks
38. ### Calculate the equivalent resistance in the Figure

Homework Statement Homework Equations / 3. The Attempt at a Solution Here is my attempt from the homework assignment. It doesn't appear that I got any points for this question and was hoping to get a little help in correcting my issues or pointed in the right direction to start over. [/B]
39. ### Calculating Total Resistance in a Parallel Circuit

Homework Statement Find total Resistance Homework Equations 1/Req= (1/R1)+(1/R2)... The Attempt at a Solution Can someone please explain me how 5 ohm R and 3ohm R are in series and then in parallel with the 2ohm R? Thanks
40. ### Solve for Equivalent Resistance - Resistor is shorted?

Homework Statement I'm studying for a test and since this is technically a textbook problem I figured I'd post here to prevent being flagged. I have the circuit redrawn. Homework Equations Series: Req = R1+R2... Parallel: 1/Req= 1/R1 + 1/R2... The Attempt at a Solution I want to understand...
41. ### Find thevenin equivalent resistance with diode.

Homework Statement I have a circuit with a diode in it. I have to find the thevenin equivalent in order to reduce the circuit to a DC source, single resistor and single diode. How do I account for a diode when trying to find Rth and Vth? Do I just remove it and have it act as a short circuit or...
42. ### Engineering The equivalent resistance of the circuit

Homework Statement Find the equivalent resistance of the circuit shown, for circuit 3.7b, the one in the upper right : https://scontent-ort2-1.xx.fbcdn.net/v/t34.0-12/14429160_641550399338143_303002326_n.png?oh=ad8d346cfcaff147c9cd7a9d2b509411&oe=57E6C47C Homework Equations Rseries=Rtotal...
43. ### Equivalent resistance of pentagon of resistors

Homework Statement Here: http://imgur.com/a/5rRgu 2. Homework Equations V=IR The Attempt at a Solution Basically from reversing the polarity of the cell and looking at a mirror image of the circuit i got the following relationships. First I(9)=0 then I(1)=-I(4) I(5)=-I(6) I(7)=-I(8). I...
44. ### Calculate R1 and R2 given equivalent resistance

Note: I have come up with a solution myself, but I am trying to understand a different approach to the problem. My textbook solves it in a different manner, and I am having trouble following along. Homework Statement The last part of the problem "determine R1 and R2 such that Rin = 200k". I am...
45. ### Thevenin equivalent resistance problem

Homework Statement Homework Equations V=IR The Attempt at a Solution [/B] I found that the current around the circuit was 5mA using kirchhoffs law ( i think) If this is true then the T.E.V should be the voltage across the 120ohm resistor which is .6V (120*5e-3). Now I'm stuck and not sure...
46. ### How to find equivalent resistance of this circuit?

Homework Statement http://imgur.com/vUoRrhO [Note: Image copy inserted by moderator] Homework Equations Req for parallel is 1/Req=1/R+1/R... The Attempt at a Solution I have never seen a circuit like this and I'm not sure as to how I would go about calculating it since there is a resistor...
47. ### Equivalent resistance between a and b -- Complex circuit

Homework Statement Homework Equations Req = [ ( 1 / R1) + ( 1 / R2) +. ...]^-1 (Parallel) Req = R1 + R2 +. . . (Series ) The Attempt at a Solution I tried to simplify the circuit by spreading it out but I guess something is wrong with my simplification since I can't arrive at the correct...
48. ### Finding current and equivalent resistance

Homework Statement The circuit consists of a battery (V0 = 48.0 V) and five resistors (R1 = 111 Ω, R2 = 182 Ω, R3 = 663 Ω, R4 = 334 Ω, and R5 = 465 Ω). Find the current passing through C, D, and G. Homework Equations V=IR The Attempt at a Solution I tried to find the equivalent resistance...
49. ### What is the relationship between resistors in a circuit?

Homework Statement I'm having trouble trying to find equivalent resistance. Here's a picture of some circuits I am trying to simplify (http://puu.sh/ngjMC/38160c3464.png) For example, in circuit a, I can see that the 84 ohm and 105 ohm resistor are in series, and that can be simplified, but...
50. ### Need some insight into an inverting op amp example

Currently working through a chapter on op amp circuits, fundamentals. Came upon this practice problem in the section on inverting op amps imgur link: http://i.imgur.com/2DrQLXk.png imgur link: http://i.imgur.com/7KRKzKC.png A working of this problem is not given. I got the correct answer...