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. O

    What's the equivalent resistance between point A and B?

    Simple as that, I've uploaded the image. I don't really care about the exact value, I would prefer just to know the method. So how would I find the equivalent resistance between A and B? Note the component in the middle is a constant current source.
  2. A

    Find the equivalent resistance between AB

    Homework Statement Find the equivalent resistance between AB. Homework EquationsThe Attempt at a Solution I could not find any Wheatstone bridge or series parallel combination. Should I use star delta transformation ? If yes, how exactly should I use it ?
  3. Domenico94

    Understanding Equivalent Impedance in a Bridge Circuit | Homework Help

    Homework Statement Hi everyone, I'm just having a little trouble with equivalent resistance in a bridge, in the image I attached. The textbook says that the way to solve this is to put R3 and ZL2 in series, that series is in parallel to the short circuit in diagonal, and then at the end we...
  4. Julian102

    How to calculate the equivalent resistance using wye delta ?

    Homework Statement https://z-1-scontent-sin1-1.xx.fbcdn.net/hphotos-xtf1/v/t34.0-12/12435980_942112312550457_1708451532_n.jpg?oh=b29a5e9b2ff96bbf0e11932d081eb25e&oe=568A9B79 [/B] We need to find the equivalent resistance along A to B ie AB Homework Equations R=(1/R1 + 1/R2+...+1/Rn)^-1 ...
  5. faradayscat

    What is the equivalent resistance from A to B?

    Homework Statement R = 10 Ohms Homework Equations Req = (1/R1 + 1/R2 + ... )(-1) Req = R1 + R2 + ... The Attempt at a Solution I honestly don't even know where to start... The obvious thing to do is 4R + 2R = 6R That's pretty much all I can come up with that makes sense... Any help?
  6. T

    Determining Thevenin equivalent resistance

    I am currently learning about Thevenin equivalent circuits and was posed with the question attached to this post. I was wondering why I3 is equivalent to the current formed by a short circuit between nodes a and b. Shouldn't the current between a and b be I1 + I2 + I3 since in a short circuit...
  7. hdp12

    Engineering Solving a Circuit with Nodal Analysis

    Homework Statement I'm in a lab and we have this circuit & question as part of the pre-lab The Attempt at a Solution I began trying to use nodal analysis to get Va & Vb & to then use Vab to get the voltage and then the current but after doing what you can see above, I stopped because I...
  8. H

    How to find the equivalent resistance?

    Homework Statement Homework EquationsThe Attempt at a Solution (a)I think there are two pairs of resistances are in parallel,one pair is the 40ohm and 50ohm resistances,and the other pair is the 30ohm and 60ohm resistances.But I'm not to sure:oldfrown: So the Req I've calculate is 152.2ohm...
  9. F

    Equivalent Resistance between A and D

    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 EquationsThe Attempt at a Solution Well I assumed that current tends to flow through wires without resistances...
  10. T

    Engineering Circuit (equivalent resistance)

    Homework Statement Find the equivalent resistance Homework Equations Req(series) = R1 + R2... Req(parallel)=(1/R1+1/R2...)^-1 The Attempt at a Solution I'm having problems understanding how to simplify this circuit. There should be parallel and series "loops" to simplify but I'm having...
  11. A

    Calculation of equivalent resistance

    Homework Statement : [/B]Given the circuit diagram, find the equivalent resistance between points P and Q. Homework Equations : [/B]ΔVloop = 0, ΔIjunction = 0 and V = IRThe Attempt at a Solution : [/B]Eliminating the wires with no resistors and solving for resistance gives me the answer as...
  12. T

    Equivalent resistance and inductance

    Homework Statement Hello, I am going to ask a rather simple question yet I wasn't able to solve. I have a circuit which I wanted to find out about the equivalent resistance and inductance. I know how to find the equivalent resistance of two resistors in parallel as well as two inductors in...
  13. S

    Find the equivalent resistance (Req) of the simple circuit.

    Homework Statement What is the equivalent resistance between points a and b in the Figure shown. Homework Equations Equivalent of two resistors (e.g R1 and R2)= R1*R2/(R1+R2) Equivalent of two resistors (e.g R3 and R4) = R3+R4 The Attempt at a Solution Step 1: 6, 12 and 4 ohm resistors...
  14. S

    Finding the equivalent resistance of an RL cct & step input

    Homework Statement Determine the inductor current i(t) for both t<0 and t>0 for the circuit shown in the attached document"Circuit 1. Homework EquationsThe Attempt at a Solution Before t=0, i=(25)/(3+2) = 5A After t=0, i(t)=i(0)e^(-t/tow) tow=L/R=4/(6/5) However, the...
  15. P

    Equivalent resistance in a complex circuit

    Homework Statement In the circuit shown, R1 = 0.810 Ω, R2 = 8.10 Ω, R3 = 81.0 Ω, and R0 = 810 Ω. See attachment Calculate the equivalent resistance of the circuit when a 7.70 V power supply is connected between points A and C. Calculate the current through R0 and R1 Homework...
  16. JustMerc

    Engineering Equivalent Resistance in series-parallel circuit

    Homework Statement This is a sample problem. I'm trying to figure it out before I do the actual homework. The issue is, the way to figure it out is not included in our notes. I'm absolutely lost (math isn't my strong point) I've also included my attempt at how I think it should be done below...
  17. H

    Engineering Find the equivalent Resistance of the circuit

    Homework Statement Find the equivalent resistance at terminals a-b of the circuit. Homework Equations Resistors in parallel : 1/Req = 1/R1 + 1/R2...+...1/Rn Resistors in series: Req = R1 + R2...+...Rn The Attempt at a Solution [/B] The resistors are in ohms and the answer is 32.5 ohms. The...
  18. 2

    Engineering Finding equivalent resistance for the given circuits

    Homework Statement Find the equivalent resistance Rab for each circuit given here (resistance values have been omitted so I can focus on understanding the concept, but I can supply them if requested). Homework Equations This problem expects me to know how to combine resistors in...
  19. S

    Calculate the equivalent resistance

    Homework Statement Ignore the internal resistance of the battery and assume it is merely a battery. Calculate the equivalent resistance of the circuit. Homework Equations 1/Req = 1/R + 1/R ... (parallel) Req = R + R ... (series) The Attempt at a Solution I know this is fairly simple but I...
  20. arpon

    What Are Alternative Methods to Wye-Delta for Calculating Equivalent Resistance?

    Homework Statement Calculate the equivalent resistance between A and B.[/B]Homework EquationsThe Attempt at a Solution I solved this problem by using wye-delta transformation. Is there any other method to solve this? The speciality in this circuit, I noticed, two of resistances are 0.[/B]
  21. B

    Finding the Equivalent Resistance

    1. Homework Statement Find the equivalent resistance Homework Equations Is=I1=I2=... Vs=V1+V2+... Rs=R1+R2+... Ip=I1+I2+... Vp=V1=V2=... 1/Rp=(1/R1)+(1/R2)+... The Attempt at a Solution Sorry the picture is sideways! Is this the correct method for finding the equivalent resistance? The part...
  22. K

    Equivalent resistance of the circuit

    Hello! 1. Homework Statement http://i0.simplest-image-hosting.net/picture/uklad.jpg Homework Equations \frac{1}{R} = \frac{1}{R1} + \frac{1}{R2} R = R1 + R2 3. The Attempt at a Solution I have been trying to re-draw the schematics, but with no avail. So far I have figured out that, looking...
  23. S

    Equivalent resistance with a short circuit

    Homework Statement Find the equivalent resistance of the circuit shown below. Homework Equations R=\Sigma_{i}R_{i} 1/R=\Sigma_{i}1/R_{i} The Attempt at a Solution I'm having a lot of trouble understanding how this circuit can be simplified. All I see is a big short circuit where the...
  24. Y

    Equivalent resistance, using node voltage analysis

    Homework Statement (I added in the R values for reference) Homework Equations GV=I KCL The Attempt at a Solution I am not concerned with the MATLAB portion of the problem, only the setup. I think what the problem wants me to do is: 1) connect a 1A test current from the...
  25. A

    Equivalent Resistance of Circuit System

    I'm having trouble with this problem. Any advice would be appreciated. I know I can't group all resistors together in one loop, but I'm not sure where to draw my loops. Should I choose the 200 ohm and 300 ohm for one parallel and the 400 ohm and 80 ohm for the other parallel? I have a...
  26. JasonHathaway

    Equivalent resistance between two nodes help

    Homework Statement Homework Equations Parallel-Series resistors combinations. The Attempt at a Solution Using an approach much like the one used to find the Thevinin resistance: 1- Open circuit between A and B (R1, R2, R3), and short circuit the voltage source. 2- (R4//R5)+R6=170 3-...
  27. S

    DC Circuit Equivalent Resistance Problem

    Hello guys, My teacher gave me a question regarding calculation of equivalent resistance, trying to solve which I'm losing my sanity. I feel a bit ashamed because this is my first post and I'm using it to ask a doubt, a little selfish of me. But it's kind of urgent so I don't really have a...
  28. JasonHathaway

    Equivalent resistance between two nodes homework

    Homework Statement Determine the equivalent resistance Req as seen by the voltage source VS (the resistance between a and b) http://i.imgur.com/A1ueQnd.jpg Homework Equations Series-Parallel combinations The Attempt at a Solution http://i.imgur.com/K1ItpF0.jpg The only...
  29. P

    Equivalent resistance question

    I'm trying to find the equivalent resistance of this circuit but I don't know where to start. The solution manual says that the 5 and 20 ohm resistors are in parallel as well as the 6 and 3 ohm resistors. Can someone explain why?
  30. P

    Equivalent resistance in circuits

    Homework Statement http://postimg.org/image/p14d9faf9/ The top two resistors are in parallel, so their equivalent resistance is 0.6 ohms. But if you were to draw the equivalent circuit, where do we place this equivalent resistance? can it be placed either where the 1 ohm or 2 ohm...
  31. N

    Equivalent resistance question

    (please check attachment) Calculate the effective resistance between A and F Initially, I thought that the first resistance is ignored and the current takes the lower path. Then 2Ω and 2Ω are in parallel giving an effective resistance of 1Ω. However, it could also be that all three are in...
  32. Saitama

    Equivalent Resistance of Infinite Resistor Chain

    Homework Statement What is the equivalent resistance of the infinite resistor chain, shown in the figure, between the points A and B? Plot the equivalent resistance versus q graph. [PLAIN]http://www.komal.hu/kep/abra/e4/b2/0d/cec528140d62b825f84ecf4d8.gif Homework Equations The...
  33. S

    Simple equivalent resistance question

    Homework Statement how many minimum no of resistances of eash 2Ω resistance can be connected to have an effective resistance of 1.5Ω Homework Equations The Attempt at a Solution I tried to put 2 in parallel,series and different combinations. After 5-10 mins of relentless...
  34. Entanglement

    Equivalent resistance of a complicated circuit

    I know that the current should flow through all the circuit but I have heard that the two vertical R in the circuit don't count I can't understand why?! I need a obvious clear explanation for this in detail thanks in advance.
  35. Entanglement

    Equivalent resistance of a complicated circuit

    I would like to know the equivalent resistance of this circuit with a clear obvious explanation, thanks in advance
  36. B

    Thevenin equivalent resistance

    i am confused at the 20v voltage since it becomes short circuit.i had started reading the circuit from the left side 1M ohm and 2k ohm are in parallel and in series with the 3k.knowing that current wants less resistant ways it will go to the killed voltage source...after that I am wasnt able to...
  37. A

    Finding equivalent resistance in complex circuit

    In my previous question , situated here, I asked about finding the equivalent resistance of the following circuit : I got some very good answers and some tips. Now what if the same circuit is modified by adding two more resistors on the free connecting wires like this : How...
  38. G

    Calculating Equivalent Resistance for a Complex Circuit - CircuitLab Homework

    Homework Statement Find the equivalent resistance of: https://www.circuitlab.com/circuit/5s3ebn/screenshot/1024x768/ Homework Equations The Attempt at a Solution I've simplified it a bit already... Just very confused in regards to which resistances are in parallel since they...
  39. N

    Equivalent resistance of simple circuit

    Homework Statement Find the equivalent resistance of the following circuit. http://img706.imageshack.us/img706/9644/zkz7.png Homework Equations none The Attempt at a Solution I am not able to find out which are resistors are in series and are in parallel.Is there any special...
  40. H

    Equivalent Resistance - Resistors Intertwined

    Homework Statement Find the equivalent resistance between terminals a and b Homework Equations Series: Req = summation of resistors Parallel 1/Req = summation of 1/resistances The Attempt at a Solution So I figured out the easy ones, and so I'm here at the moment...
  41. K

    Equivalent resistance in a parallel circuit

    Homework Statement Prove that the equivalent resistance in a parallel circuit with 2 resistors with resistance R1 and R2 is always lesser than the resistance of either resistor. Homework Equations Rt= (R1 x R2)/(R1 + R2) The Attempt at a Solution I tried starting from R1 + R2...
  42. A

    Difficult : Calculate equivalent resistance of the circuit problem .

    Homework Statement Calculate the total equivalent resistance between A and D - ( All resistors are 1 ohm ) Homework Equations - The Attempt at a Solution The only thing I can see is that the two straight 1 ohm resistors are in parallel , giving 1*1/1+1= 1/2 resistance. But what...
  43. H

    How to calculate thevenin's equivalent resistance

    when i short the batteries to find the rth, i can't get whether is should put delta to star transformation to find thevenines resistance? can some one tell me how to calculate thevenines equivalent resistance in the figure shown... step by step
  44. J

    Kirchoff's Rule(How do I find equivalent resistance?)

    Homework Statement Please take a look at the attachment to see the circuit. My question is how do I find the equivalent resistance of this circuit? I have done the other two parts but this part has got me stumped. I also drew my currents on the picture. Homework Equations The...
  45. T

    Equivalent Resistance (Prep for Lab on DC circuits)

    Homework Statement Use the circuit shown to answer the following questions. At time t = 0 the switch in the circuit is closed. Answer the following questions after the switch in the circuit is closed. What is the equivalent resistance of the circuit given R1 = 5 , R2 = 5 , R3 = 4 , R4 =...
  46. H

    Find equivalent resistance in this circuit

    Homework Statement http://session.masteringengineering.com/problemAsset/1515645/4/Steif.ch02.p28.jpg Find the equivalent resistance between node A and B, knowing that Rab = Vab/Iab Homework Equations KCL and KVL, I know. The Attempt at a Solution There is nothing in series or...
  47. G

    Equivalent Resistance Simulator

    Hi, Does anyone know of a simulator where I can make a circuit and the simulator tells me the equivalent resistance? I need one that will allow me to put resistors in parallel, series, del to y etc.. I can't find one or know of a way just confirming that my original calculations of the...
  48. G

    What is the Ideal Current Source and How Does it Affect Circuit Design?

    http://img7.imageshack.us/img7/6238/capturealh.png My gut tells me that these resistors are in parallel. However something tells me that it might be more complicated but I'm not sure. Do I find the equivalent resistance by just simply adding them together as if they were in parallel to...
  49. E

    What is the concept of equivalent resistance in electrical circuits?

    1.What is the equivalent resistance between A and B? (The diagonals do not intersect) 2.equations: I don't think I can provide any equation u don't know... Then again my last 2 posts were deleted... so no mistake this time... :D Rs=R1+R2+... 1/Rp=1/R1+1/R2+... concept of voltage,current etc...
  50. D

    What is the Equivalent Resistance in a Series Circuit?

    Hi guys,I'm new here and maybe I'm posting this homework in a wrong part of the forum.I tried to find the equivalent resistance.It may be a simple homework but I am learning first for the electricy physic.I tried to find Re first R2+R3=4 Ω and than found Re=1/4 Ω + 1/2 Ω + 1/2 Ω can i slove it...
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