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. D

    Engineering RLC circuit - Differential equation - Stationary current calculation

    Homework Statement I'm decent with differential equations for RLC circuits, and I KNOW the stationary current will be zero, but I need help to work it out mathematically, because my maths gets me -2.4A (...) L: 0.05H C: 0.04F R: 3 Ω U (source) = 1 V I've got the transient solution: c1e-10t +...
  2. B

    RLC circuit driven by a 'Real' toroid

    I'm currently wanting to model an RLC circuit that is driven by a toroid transformer with a driving current, I(t). See image below. In physics class, I've done similar problems with 'ideal' toroids and a simple R circuit. What I'm struggling with is how to model a 'real' toroid...
  3. C

    RLC circuit, finding relations and forming a differential equation

    Hello. I'm having a hard time solving this homework question, even though I know I shouldn't... but well. Here's the problem : -The K switch is closed for a long time, so as to be in a steady state. What's the electric charge of the capacitor ? Infer vs tension from this. Which...
  4. N

    Heat dissipated in an RLC circuit

    Homework Statement A 4 Ω resistor, 14 mH inductor, and 99 µF capacitor are connected in series to a 65 V (rms) source having variable frequency. Find the heat dissipated in the circuit during one period if the operating frequency is twice the resonance frequency. Answer in units of J...
  5. J

    How do I find di_L(0)/dt for a second order RLC circuit after the switch opens?

    http://imgur.com/6aAMV So I need to find the current labeled as a function of time. THe switch opens at t=0 and I drew the circuit after the switch opens. I found the initial current to be -4 and the voltage on the capacitor to be 8. I'm having trouble trying to find di_L(0)/dt. I...
  6. T

    Engineering RLC circuit and resonance frequency

    Homework Statement Find an equation for the resonance frequency. Then find R L and C given that the resonance freq is 10 Hz. Homework Equations Wrote below The Attempt at a Solution y(jw) = (1 / R + jwl) + jwC is the basic equation.. after simplifying and setting imaginary part to...
  7. S

    RLC Circuit Homework: Finding Voltage Sources and Solutions

    Homework Statement See Attached Homework Equations The Attempt at a Solution I used the Pythagorean theorem Vs= the square root of Rv squared plus (Lv-Lc) squared and came up with a voltage source of 100 volts AC. Right?? So how do I figure the voltage between A,C and B,D? I...
  8. D

    Measuring current in RLC circuit

    Homework Statement I've recently completed a experiment involving a Driven series RLC circuit. The potential difference across R " a variable resistor >> internal resistance of inductor" was measured. When calculating the current from the PD across R, should I include the internal resistance...
  9. S

    Best RLC circuit for Low Frequency underdamped resonance

    Hi all, I am tring to design an RLC circuit with a low (<3Khz) resonance out of RLC circuit elements. The circuit must be underdamped. The lower the damping the better. Originally I planned (and built) a RLC circuit with R=.1, C=100uF, L=100uH. On paper this gives a resonance at 1590...
  10. F

    RLC Circuit Calculations - How Do Wattmeters Work?

    Homework Statement There are two circuits I don't entirely understand. I am also new to calculations with complex numbers and when to and when not to use them, so be easy on me. Anyways, the point is to find out what the different meters are showing, when you are given the initial voltage and...
  11. Z

    Engineering Capacitor charge time on DC RLC circuit

    Homework Statement Inductor, resistor and a capacitor is connected to a DC source in series. DC source is 220 V Capacitance is 10F Inductance 5H Resistor 22 ohm Vc(0) = 50V Question is asking for the charge time of the capacitor, when it gets charged fully and then it starts to act...
  12. FOIWATER

    Maple Maple issue - inverse laplace transform equation from a basic series RLC circuit

    maple issue -- inverse laplace transform equation from a basic series RLC circuit Pretty simple for some of you I know, but I have a laplace transform equation from a basic series RLC circuit ((sV-v(0))/L+si(0))/(s^2+sR/L+1/LC) = I(s) I want to take the inverse laplace of it, I am given all...
  13. O

    Energy Conservation in RLC circuit

    Homework Statement Assume the current in a series RLC circuit is given by I = ACω(sin(ωt) + \frac{α}{ω}cos(ωt))e^{-αt}. Calculate the energy stored in the circuit at t=0. Then calculate the energy stored in the circuit one-quarter cycle later, at t=\frac{\pi}{2ω}. Verfiy that the...
  14. D

    Engineering Impedance for series-parallel RLC circuit problem

    This is my first time posting so forgive me if I screw it up. I have attempted to attach the file, I hope I have done so correctly. I am trying to solve a series-parallel RLC circuit problem. I have a 220Ω resistor in series with 180Ω resistor, a 1mH inductor and a .47μF capacitor all in...
  15. H

    Engineering Finding VL(t) and Vc(t) in a RLC circuit with sinusoidal excitation

    Homework Statement Find VL(t) and Vc(t) in the circuit below Where Vs = cos(200\pit) V Homework Equations \alpha = \frac{1}{2RC} ω0 = \frac{1}{\sqrt{LC}} \omega0 = \sqrt{\omega^{2}-\alpha^{2}} The Attempt at a Solution Well, I found the total capacitance C = 1.5 uF Then, I found \alpha...
  16. beyondlight

    Engineering Frequency Response and Output of an RLC Circuit

    Homework Statement http://tinypic.com/view.php?pic=doxum1&s=6 Consider a casual LTI system implemented as the RLC circuit above. x(t) is the input. And y(t) is the output across the capacitor. a) Find the differential equation relating x(t) and y(t) b) Determine the frequency response of...
  17. C

    Engineering Black box Conumdrum: CL or LC order in a RLC circuit

    Hey everyone. Since it is nearest the end of the summer semester for the Lab component of my classes, Our professor is having do the 'Black Box' project. From the information he gave us, there are three component in a L-configuration, an inductor, capacitor, and a resistor. The Box itself had...
  18. S

    Various RLC Circuit Problems (Resonance Frequency, Phase, Current)

    Homework Statement An RLC circuit has L = 20mH, R = 20kΩ, C = 250μF. 1) Calculate the resonance frequency for this circuit. 2) For a frequency ω=400 rad/s, determine the phase angle and the circuit impedance. 3) Using ε = 30[V]sin(ωt), calculate the current in the circuit. This will be a...
  19. M

    Mixed parallel & series RLC circuit

    Homework Statement pic: www(dot)freeimagehosting.net/hbnem Calculate impedance , current and power factor Homework Equations The Attempt at a Solution pic: www(dot)freeimagehosting.net/xmy2b First we solve parallel part. In parallel resistor and inductor are sharing voltage...
  20. R

    Calculating Power Factor in and RLC Circuit

    Homework Statement An RLC circuit has a resistance of 105 ohms, an inductance of 85.0 mH, and a capacitance of 13.2 μF. What is the power factor for this circuit when it is connected to a 125-HZ ac generator? Homework Equations Well I'm not completely sure which equations to use, so here's some...
  21. M

    What Equation Should I Use for Calculating Total Impedance in RLC Circuits?

    Homework Statement Hello again! We have been given a couple of more advanced problems where the components are placed in series parallely. Check the image, the question is regarding what equation to use, in order to calculate the total impedance of the circuit. Homework Equations I...
  22. M

    Finding current in parallel RLC Circuit

    Homework Statement A parallel RLC circuit with every component in parallel. The resistance is 120 Ohm, the reactanse over the capacitor is 150 Ohm and the reactanse over the inductor is 70 Ohm. The total current is equal to 100mA. Calculate the current passing through the inductance...
  23. J

    RLC circuit resistance, inductance and capacitance

    A series RLC circuit connected to a 100-V 60-Hz source draws a current of 2.5 A. The measured power factor for the circuit is 0.7 leading, and the inductive reactive power is 300VAr. Calculate the resistance, inductance and capacitance of the circuit and show the corresponding impedance...
  24. D

    RLC Circuit - Voltage Across Resistor

    Homework Statement Find the voltage across the resistor. Homework Equations V = L*di/dt I = C*dv/dt The Attempt at a Solution I'm not too worried about the differential equation part but I need some help setting up the circuit for me to start the process. Since the current through the...
  25. K

    Engineering Commutation process in RLC circuit

    Homework Statement Still can't figure this one out. All data is on the picture attached. I have to find the current flowing through E1 after E2 is connected and draw a graph as it changes in time of the process. I can't do the equations when t=0 Homework Equations dUc/dt|t=0...
  26. N

    How Long Does It Take for a High-Resistance RLC Circuit to Lose Half Its Energy?

    Homework Statement Consider a simple RLC circuit. If R >> (4L)/C , compute approximately how long it takes for the circuit to lose half of the initial energy stored in the system. (There is no circuit drawing given; the problem assumes a general RLC circuit) Homework Equations The...
  27. M

    What is the frequency of the source in the given RLC circuit?

    Homework Statement In the AC circuit shown, the potential difference across the capacitor and the resistor, V(BD), is 24 V(rms). Similarly, the potential difference across the inductor and the resistor, V(AC) is 24 V(rms). What is the frequency of the source...
  28. M

    Rlc circuit with ac current source

    Homework Statement An AC current source, 1 ∠0° A, with angular frequency 1 rad/s is to be applied to the input terminals of the circuit. Circuit is RLC, the current source is in parallel with a 1F capacitor which is in parallel with a 1H inductor which is in series with a 1Ω resistor. I...
  29. P

    Engineering Resonate Frequency of Parallel RLC Circuit

    Homework Statement Determine the resonant frequency of the circuit in Fig 14.28 (See attached) Homework Equations \begin{array}{l} {\rm{How is }} \to {\omega _0}0.1 - \frac{{2{\omega _0}}}{{4 + 4\omega _0^2}} \\ {\rm{derived from }} \to j{\omega _0}0.1 + \frac{{2 - j{\omega...
  30. L

    Engineering How to find overshoot and undershoot in an RLC circuit?

    Homework Statement RLC circuit as shown in the attachment. Input is a pulse, of frequency 1MHz, 5v. Rise/fall time 1ns. How to find the voltage at the capacitor. In simulation, I see overshoot and undershoot. But how do I find the overshoot/undershoot amplitude mathematically? Ringing...
  31. K

    Engineering Finding current in a RLC circuit using kirchhoff laws

    Homework Statement Find current flowing through E1 ( find I1). Homework Equations I see 6 currents, atleast until the capacitor is charged, what i find confusing are the branches without any resistance and they seem to mess up my equations. The Attempt at a Solution 1st kirchhoff's law...
  32. E

    Engineering Overdamped RLC Circuit Faulty Question?

    Is this a faulty question? I don't believe that there is one value of L that would make the circuit overdamped.
  33. T

    RLC circuit, need some help with the intuition behind inductors.

    Homework Statement I attached a picture of a sample problem that I was confused about. What I don't understand is why the V2 voltmeter would read 0 volts (according to the answer key). This is because I thought that an inductor produces an induced emf and current. So wouldn't the voltmeter...
  34. T

    How Does Power Balance in a Driven RLC Circuit?

    Homework Statement For a driven RLC circuit, compare the power delivered by the source to the power dissipated as heat in the resistor. Homework Equations P_{avg} = I_{rms}*V_{rms}*cos(\phi) The Attempt at a Solution My thinking was that the power dissipated in the resistor would...
  35. T

    Engineering RLC Circuit problem using laplace transforms

    Homework Statement The switch at S is closed at time t=0 and a constant ... va−vh=v0 is applied. Use Kirchoff's laws to write 3 equations for i,i1,i2, and q(t). What is the relation between q(t) and i,i1,i2? Given that the charge on C and all currents are initially zero, find an ODE for i1(t)...
  36. S

    Engineering Understanding Second Order RLC Circuits: Solving for Differential Equations

    Homework Statement Hello all, Representing RLC circuits via differential equations is rather new to me, in fact differentials as an entirety are new for me. Essentially I am looking for clarification regarding this type of question and whether or not I am doing it right. Thanks in advance...
  37. A

    Engineering Total impedance of a RLC circuit

    Hi, I need to write a c++ program that calculates the total impedance of a simple RLC circuit. I'm given the values of each component (resistance, coil, condenser). The programming part is not a issue however I can't find the formulas for the impedance on the internet. Can someone help me out...
  38. G

    Phase Shift in RLC Circuit with Increased Inductance

    hi i have a textbooks that says that if you have a driven RLC at its resonance frequency and now you increase the inductance, then you would measure a phase difference between the external emf and the voltage at the capacitor that is now greater than pi/2 unfortunately, i do not know how to...
  39. G

    Engineering Parallel RLC circuit phasor diagram

    I am having difficulties with phasor diagram for Is and Vs of an parallel RLC circuit. I have calculated all values but not sure how to use phasors. Impedance Z has angle +65°. Current Isupply +30° and Vsupply is Z*Is= Vs at angle 95° But with parrallel network V is the reference so I guess it...
  40. C

    Understanding Energy in RLC Circuits: Initial Conditions

    Homework Statement Please check picture http://i.imgur.com/YMQBR.png Homework Equations The Attempt at a Solution Shouldn't all the energy be 0 at beginning? Thanks!
  41. D

    MATLAB Control Systems RLC Circuit Queries

    Hi there, we recently completed a laboratory session on MATLAB relating to an RLC Circuit and arrive at a code and relevant inputs and got our graphs as shown below. I was just wondering if anyone know if these are correct and make any sense? Or any other comments appreciated. We also have...
  42. W

    Parallel RLC Circuit: Using General Impedance Equation

    Quick Question... Given: Can I still use the general impedance equation for parallel RLC circuits even though the resistors are not in parallel with the other components? Substituting the two resistors for a single resistor with the equivalency resistance?
  43. Z

    Engineering RLC Circuit Differential Equation

    Homework Statement For RLC circuit determine and solve differential equation. R, L, C, E0 values are constants, E = E(t) = E0*sin(ω*t) (E is marked as V in the image). Then make program which calculates values of I(t) when R, L, C, E0, ω are given. In short, I need to get function I(t), so I...
  44. A

    Derive equation for RLC circuit

    how to get this equation: Vout/Vin = [RL]/[-[ω][/2]+jω(R/L)+1/(LC)]
  45. W

    How do I solve a Series RLC circuit?

    Edited for assignment purposes...
  46. P

    Engineering Effective Voltage in series RLC circuit

    Homework Statement Given a series RLC circuit with a sinusoidal voltage input, find the effective voltage across each element. Given: 1) If the effective value of the source voltage is 1 V, the effective value of the current is 1 amp. 2) i(t) lags v(t) by 45 degrees 3) L=1H 4) w=2...
  47. S

    RLC Circuit - 2. Order differential equation solution

    Homework Statement Hey guys. So we've been working on a RLC circuit, where the subject is oscillations. We accomplished to work out a differential equation, for this specific circuit, however solving it is a completely other part of the problem. We're completely stuck here and hopefully...
  48. W

    Why are Vc and Vl larger than Source current at resonance in an RLC circuit?

    I'm looking at this question and I can't seem to come up with an answer, don't the VL (inductive voltage) and Vc (capacitor voltage) just cancel each other out leaving you with Vr (resistance voltage) as the source voltage, but I don't see why VL and Vc are much higher than the source voltage...
  49. J

    RLC Circuit (with critical and heavy damping)

    Homework Statement Consider a RLC circuit. a) Suppose the parameters are chosen to give critical damping. The capacitor is charged to a voltage of V₀ and at time equal to zero the switch is closed. Find the time at which the magnitude of the current reaches a max, and find the value of the...
  50. A

    Writing Output in State Space Form: RLC Circuit Example

    the general form of state space output is y=cx+du which means that output is linear combination of state variables and inputs my question is can we write output in this form when our output is not combination of state variable for example in rlc circuit state variables are vc and IL now if we...
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