What is Rlc circuit: Definition and 305 Discussions

An RLC circuit is an electrical circuit consisting of a resistor (R), an inductor (L), and a capacitor (C), connected in series or in parallel. The name of the circuit is derived from the letters that are used to denote the constituent components of this circuit, where the sequence of the components may vary from RLC.
The circuit forms a harmonic oscillator for current, and resonates in a similar way as an LC circuit. Introducing the resistor increases the decay of these oscillations, which is also known as damping. The resistor also reduces the peak resonant frequency. In ordinary conditions, some resistance is unavoidable even if a resistor is not specifically included as a component; an ideal, pure LC circuit exists only in the domain of superconductivity, a physical effect demonstrated to this point only at temperatures far below and/or pressures far above what are found naturally anywhere on the Earth's surface.
RLC circuits have many applications as oscillator circuits. Radio receivers and television sets use them for tuning to select a narrow frequency range from ambient radio waves. In this role, the circuit is often referred to as a tuned circuit. An RLC circuit can be used as a band-pass filter, band-stop filter, low-pass filter or high-pass filter. The tuning application, for instance, is an example of band-pass filtering. The RLC filter is described as a second-order circuit, meaning that any voltage or current in the circuit can be described by a second-order differential equation in circuit analysis.
The three circuit elements, R, L and C, can be combined in a number of different topologies. All three elements in series or all three elements in parallel are the simplest in concept and the most straightforward to analyse. There are, however, other arrangements, some with practical importance in real circuits. One issue often encountered is the need to take into account inductor resistance. Inductors are typically constructed from coils of wire, the resistance of which is not usually desirable, but it often has a significant effect on the circuit.

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  1. Marcus95

    Width of Resonance in RLC-circuit

    Homework Statement In an undriven RLC-circuit, the characteristic time of the capacitor, ie the time taken for the amplitude of the capacitor voltage ## V_c ## to drop by a factor e, is ## T = 2L/R ##. We now have a RLC-circuit which is driven by a AC voltage of variable frequency ## \omega ##...
  2. R

    Q factor of an AM radio RLC circuit

    Homework Statement Suppose you want to use a series RLC circuit to tune in your favorite AM radio station which broadcasts at a frequency of 1.20 MHz. You would like to avoid the obnoxious easy listening station which broadcasts at 1.10 MHz, right next to the one you like. In order to achieve...
  3. E

    Engineering RLC Circuit, Find Diff Eq for VC - Can someone check my work?

    Homework Statement Find the differential equation for VC Circuit #1 Circuit #2 Homework Equations KCL The Attempt at a Solution Circuit #1: Node VC: ##\frac{V_C-V_{in}}{R_1}+\frac{1}{L_1}\int_{0}^{t}(V_C-V_2)+C_1\dot{V_C}=0## Node V2: ##\frac{1}{L_1}\int_{0}^{t}(V_2-V_C)+\frac{V_2}{R_2}=0##...
  4. E

    Engineering RLC circuit - Can someone check my work?

    Homework Statement https://www.physicsforums.com/attachments/upload_2016-11-25_8-51-19-png.109406/ Find the differential equation for Vo Vin is a square wave Homework Equations KCL/KVL The Attempt at a Solution At Node V1: ##\frac{V_1-V_in}{R_1} + \frac{1}{L_1}\int_{0}^{t}(V_1-V_2) = 0##...
  5. E

    Engineering Find the natural response of the RLC circuit

    Homework Statement [/B] Find the natural response V1 is a squarewave Homework Equations KCL, KVL The Attempt at a Solution How would I find the natural response using differential equations? Am I doing it right? by KCL \frac{V_1-V_{in}}{R_1}+\frac{1}{L}\int_{0}^{t}V_1(t)dt +...
  6. E

    Engineering Solving RLC circuit using differential equations

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  7. mkematt96

    Engineering V max of a RLC Circuit. Where did I go wrong?

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  8. garylau

    Where is the RLC circuit time constant"2L/R" coming from?

    Sorry i want to ask a question about RLC circuit~ i don't understand where is this "2L/R"coming from and also i don't know what is the function of this" time constant"(it is meaningless in physical sens?e) in the note it states"that the time constant for reaching the steady state here..."...
  9. gmm

    Is an Underdamped RLC Circuit Possible?

    Sorry Guys, I posted this thread in the wrong category. I Just posted it were it's supposed to be
  10. I

    RLC Black box at different frequencies

    Supposed there is a black box connect to an AC circuit. Inside the black box, there are either a resistor connected with a capacitor or a resistor connected with a inductor. They can be connected either in series or in parallel. The total impedance and phase shift of the black box at 2 different...
  11. F

    Engineering Q of RLC circuit, confused with provided answer

    Homework Statement The main question is to derive the Q of the series RLC circuit. This book shows the whole solution but I have a question about a part of their answer. Basically I want to know how ##\frac{1}{2}CV_{Cmax}^2 = \frac{1}{2}C(\frac{i_{max}^2}{wC}^2)## to me it looks like they are...
  12. Kfir Dolev

    I Is it possible to build a phase shifter from RLC components?

    Say you have a circuit component with impedence Z(\omega). Is it possible combine it in some way to resistors, capacitors, and inductors, so as to shift the phase of the impedance by a constant?
  13. brainphysics

    Engineering Figuring Out a General Solution for RLC Series Circuit

    So, I have been trying to come up with a general solution for dI/dt in an RLC circuit. I have attached the work I have done so far. I don't know where but I am making a mistake and the waveform is not coming out right. Would really appreciate a look over my work to see if I made any obvious errors.
  14. YellowBelliedMarmot

    Engineering Thevenin Equivalent of AC RLC Circuit w/ Dependent Voltage

    Homework Statement Find Vth and Zth. frequency = 2kHz Homework Equations w = 2 * (pi) * f ZL = j w L ZC = -j / (w * C) V = I*Z ZR = R The Attempt at a Solution At first I tried using nodal analysis which I receive the value V = 0 v. I believe this is because this circuit only has dependent...
  15. Hapusss

    RLC Circuit Question For final exam

    Homework Statement [/B] (a) Write down sucient number of equations to determine all the currents i1, i2 and I (you do not need to solve the equations) (b) At the instant the battery is turned on, what is the current I running through the circuit? (c) After waiting for a suciently long time...
  16. A

    Phase problem in a damped RLC circuit

    Homework Statement The expression for electric charge on the capacitor in the series RLC circuit is as follows: q(t)=A*exp(-Rt/2L)*cos(omega*t+phi) where omega=square_root(1/LC-R^2/4L^2) What is the phase phi, if the initial conditions are: q(t=0)=Q I(t=0)=0 Homework Equations The damped...
  17. Titan97

    B RLC Circuit Analysis: Phase Difference & Impedance Modulus

    In an RLC series circuit let applied EMF be given ##V=V_0\sin\omega t##, $$Z=Z_C+Z_R+Z_L=R+i\left(\frac{1}{\omega C}-\omega L\right)$$ $$|Z|=\sqrt{R^2+\left(\frac{1}{\omega C}-\omega L\right)^2}$$ Then $$i(t)=\frac{V(t)}{Z}=\frac{V_0e^{i\omega t}}{R+i\left(\frac{1}{\omega C}-\omega L\right)}$$...
  18. Drakkith

    Charge on Capacitor in RLC Circuit

    Homework Statement At t = 0, the charge stored on the capacitor plates is maximum in an oscillating series RLC circuit. At what time will the maximum possible energy that can be stored in the capacitor fall to one-eighth of its initial value if R = 7.20 Ω and L = 21.0 H? The differential...
  19. Y

    Linear Algebra - Solving AC RLC circuit

    Homework Statement So yeah I'm doing a project were I get to create a problem. I would like to learn how to solve a AC RLC circuit using linear algebra. I'm trying to find all of the currents on the edges of the graphs and find all of the voltages at the nodes connecting the edges. I don't...
  20. ReidMerrill

    How Do You Calculate Impedance in an RLC Circuit at 3000 Hz?

    Homework Statement A series RLC circuit consists of a 60.0 Ω resistor, a 2.30 mH inductor, and a 690 nF capacitor. It is connected to an oscillator with a peak voltage of5.80 V . Part A Determine the impedance at frequency 3000 Hz. Part B Determine the peak current at frequency 3000 Hz. Part C...
  21. R

    Time for capacitor charging in RLC circuit.

    Homework Statement In series RLC circuit how much time it takes for capacitor to charge to 0.63% of source voltage..? time constant is the time taken by a capacitor to charge to 0.63% of source voltage and in rc circuit time constant is RC. but what about for capacitor in series RLC circuit...
  22. P

    Finding values for an RLC circuit graphically

    Homework Statement Determine ##q(t=0)##, ##i(t=0)##, the phase difference ##\phi##, angular frequency ##w## and the time constant ##\tau## from the graph of the capacitor waveform below:(pulse voltage source) For this circuit we have ##q(t)=Ae^{-\frac{t}{2\tau}}\cos(\omega t+\phi)##...
  23. S

    Measuring Voltage across Resistor in Series RLC Circuit

    I was experimenting with resonant frequency of a series RLC circuit: 5V AC source 10 ohms resistor 100microF capacitor 46mH inductor Resonant frequency is calculated to be around 74.2Hz. So I set the AC source to resonant frequency 74.2Hz and measured the voltage across the 10 ohms resistor...
  24. Aristotle

    Engineering KVL for a RLC circuit given current direction and polarity o

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  25. Captain1024

    Engineering Analysing a 3-Loop RLC Circuit and Finding State Equations

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  26. A

    Quick question on Parallel RLC circuit (Conceptual)

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  27. lulzury

    RLC Circuit time for Energy to drop to 20% of initial value

    Homework Statement In an oscillating series RLC circuit, with resistance R and inductance L, find the time required for the maximum energy in the capacitor during an oscillation to fall to 1/5 its initial value. Assume q = Q at t = 0 Homework Equations ## U(t) =...
  28. hdp12

    Engineering Given RLC circuit to find V over load & other complications

    Homework Statement In my Intro to EE class we have a homework assignment with the following problem: I think I finished part a but want to make sure that I am doing the problem correctly before I move on to the next part. Homework EquationsThe Attempt at a Solution
  29. S

    RLC Circuit Homework: Find L, Z, I, and P

    Homework Statement A series RLC circuit has R=75 ohms, C=20 mF and a resonance frequency of 5.0 kHz. (i) What is the value of inductance? (ii)What is the impedance of the circuit at residence? (iii)What is the rms current at resonance if the rms voltage of the power supply is 120 V? (iv) How...
  30. F

    Finding the Steady State Solution for a RLC circuit

    Homework Statement An ideal AC voltage source generating an emf V (t) = V0 cosωt is connected in series with a resistance R, an inductance L, and a capacitance C. a) Find the steady-state solution for the charge, q(ω,t), which is of the form q0(ω)cos(ωt− δ(ω)). b) Find the steady-state...
  31. Roy Fokker

    Engineering Second Order RLC Circuit: Find DEQ & Circuit for Time t>0

    Homework Statement Find DEQ, circuit for time t>0. Homework Equations Ic= CdVc/dt Vl=LdiL/dt The Attempt at a Solution At T=inf L Short , C Open IL(inf)=4mA, VL(inf)=0, Ic(inf)=0, Vc(inf)=0 T=0- All at 0 T=0+ L=Open C=Short IL(0+)=0, VL(0+)=0, Ic(0+)=4mA, Vc(0+)=0 20v=L diL/dt + Vc +...
  32. Luke Cohen

    Maximum energy stored in a capacitor? RLC circuit

    Homework Statement The current in a series RLC circuit leads the generator voltage by φ = 30°. The circuit, containing an inductor L = 400 mH and a resistor R = 50 Ω, is driven by a generator operating at ω = 100 rad/s with a maximum emf of 10 V. The capacitance is unknown. The first question...
  33. A

    Calculating Impedance of a RLC Circuit Connected to a 60 Hz AC Source

    Homework Statement A series RLC circuit is connected to a 60 Hz AC source which produces an amplitude of εmax=20 V. The circuit element values are R= 20 Ω, L= 20 mH, C= 150 μF. Calculate the total impedance of the circuit. Homework Equations Xc=1/ωC XL=ωL Z=√(R^2 +(XL-Xc)^2) tan φ = (XL-Xc)/R...
  34. S

    Engineering Waveform of R,L,C in DC circuit

    Homework Statement Draw a time-depended waveform of all components in DC RLC circuit. R=4*1,412 L=1,6 mH C=0,2 mF Udc=15 V Homework EquationsThe Attempt at a Solution DoCircuit simulator I am a bit confussed with this homework because I am aware that capacitor do not conduct a current in DC...
  35. A

    Engineering Quality factor and freq bandwidth in a series RLC circuit

    Homework Statement How and why does quality factor change in a series RLC circuit when the resistance in the circuit increases? I've made a small experiment circuit which looks like one in the picture: The current frequency is 1 kHz and the voltmeter should show 2V throughout the whole...
  36. R

    Solving Series RLC Circuit: Vrms Across Capacitor & Inductor is Zero

    Homework Statement Given a series RLC circuit: R = 10 Ω L = 0.1 H C = 2 μF Power Source: V = 5sin(500t) If you could change the capacitance what C would you select so Vrms across the capacitor and inductor is zero? Homework Equations ω2 = 1/LC The Attempt at a Solution My instructor's...
  37. P

    Find resistance of inductor in series RLC circuit

    Homework Statement We have a resistor of 350 Ohm, an inductor of 0.15H and a capacitor of 10 microfarad, connected in series to an AC source of voltage 240 V and frequency 50 Hz. The measured effective voltage over the resistor is 180V, and over the system of the both the inductor and the...
  38. W

    Calculating inductance of an LR and RLC Circuit?

    Homework Statement For both the LR and RLC circuit, a function generator is used to create a 1000 Hz square wwave of maximum amplitude. 1) For the following LR circuit, the resistance is set to a 100 Ohms. Determine the inductance, L. How does the inductance vary if the resistance were...
  39. B. Vane

    RCL Circuit: 2 Resistors, 1 Capacitor, 2 Inductors

    Homework Statement NOTE: Image uploaded with thread shows problem in clearest possible form. V = (45v)sin(80[pi] t) Resistors 1 and 2 = 50 Ohms Inductor 1 = 20 mH Inductor 2 = 2.5 mH Capacitor = 50 uF a) Find the power dissipated by each resistor. b) At what frequency will both resistors...
  40. T

    Engineering RLC circuit -- determine the voltage across each element

    Homework Statement For the series RLC circuit shown in Fig. Q8, determine the voltage across each element, and draw a complete phasor diagram. Homework EquationsThe Attempt at a Solution Total Impedance: Z = R+Xc+Xl = 75 - 60j + 25j = 75-j35 Z = 82.76∠-25.02 (Phasor form) Total...
  41. C

    Analysis of RLC Circuit v(t): Find Voltage with Ohm's Law

    http://imgur.com/hAzf2zP So I found the circuit is series, w0 and a0 equal 20 so it is critically dampened. For V(inf) I used current divider to get the equation (.1 A *120 ohm)/40 ohm = .3 A. Then I used ohms law to find v(t) = .3*120 = 36 V. I then wrote down the circuit at t<0, t>0, and...
  42. W

    Resonant RLC circuit and in inductance

    1. A resonant RLC circuit can be used as an amplifier for a certain band of frequencies around the resonant frequency. Consider a series RLC circuit as an audio band amplifier with an AC voltage source as the input, and the voltage across the 8.0Ω resistor as the output. The amplifier should...
  43. P

    Engineering RLC Circuit (lab session doubt)

    Homework Statement I have to answer a few questions about a lab session I did (university) and I'm really stuck with this one. The objective of the lab session was to find the self inductance (L) of a solenoid. In order to do that, I had a function generator exciting a solenoid with a high...
  44. S

    Finding the current Io for t>0 in a RL circuit

    Homework Statement For the circuit in the attached file, find io (current) for t>0 Homework Equations The Attempt at a Solution I have included an attachment which shows the solution. However, I will copy the solution here as well for reference: When t<0, the switch is closed, the inductor...
  45. jcoona

    Engineering RLC Series Circuit: Understanding Inductor Behavior

    Homework Statement I am not sure how an Inductor behaves in an RLC Series Circuit Homework Equations The Attempt at a Solution I know that after a long time, that the circuit above, the voltage in the capacitor is max. Generally, I also know that the current through an inductor after a...
  46. S

    Engineering Finding the component values of a RLC circuit

    What methods could I utilise to find the individual values of the components - resistor, inductor and capacitor - of a series RLC circuit using an oscilloscope, signal generator and 10 ohm resistor. Where each component can be isolated in order to find the voltage etc. I've already found the...
  47. J

    Setting up an LRC series circuit with coupled coils

    Homework Statement I have been trying to set up an LRC series circuit where in place of an inductor we have a pair of coupled coils. My aim is to determine the resonant frequency in the circuit when the voltage across the resistor or the current in the circuit is at a maximum. I am using a...
  48. 2

    Transforming DC to AC: The Role of Inductors and Capacitors in RLC Circuits

    I have only just found out about inductors, and am trying to figure out how a circuit with an inductor and a capacitor could change dc current to ac current. With the set up of the circuit, would it suffice just to have the dc supply with a 'gate' that stops/allows through the dc current with a...
  49. B

    Question about the RLC circuit

    In the direct current circuit, when you have a switch and you turn it on, you get the coil to generate a current to the opposite direction but the magnitude isn't big enough to offset the main one. But in the case of alternating currents, the coil seems to generate enough current up to the...
  50. B

    Instantaneous currents in RLC Circuit

    Homework Statement I am completely stumped on this problem: In this circuit: v= 30.0 R = 400 ohms C = 2.50 micro coulombs L = .300 H The switch (pretend you see one) is close at t=0 Current i1 flows through L and current i2 flows through C QUESTION: At what time (t) does i1=i2 ...
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