# 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. ### How to obtain amplitude of current in parallel RLC circuit?

If we apply KVL to the three separate loops involving the AC voltage we obtain expressions for ##I_R, I_L##, and ##I_C##. $$-V(t)+I_R(t)R=0$$ $$\implies I_R(t)=\frac{V_0}{R}\sin{(\omega t)}$$ $$-V(t)=-L\dot{I}_L(t)$$ $$\implies I_L(t)=\frac{V_0}{\omega L}\sin{(\omega t-\pi/2)}$$...

27. ### Engineering AC Source driving an RLC circuit....

Homework Statement 10 v, 100 hz goes into a circuit of a 1o resistor, a 1o inductive reactance and a 1o capacitive reactance that are in series. What is the current. What is the V across the cap. Homework Equations and the attempt at a solution[/B] So I know I = V/Z and Z = sqrt( R^2 +...
28. ### Engineering RLC circuit solved with Laplace transformation

Hi, i need some help here. Can you help me?:sorry: Here is the problem. Exercise statement: The switch have been closed for a long time y is opened at t=0. Using Laplace's transtormation calculate V0(t) for t ≥ 0 This is what i made to solve it: 1) I know while the switch is closed, the...
29. ### Verifying Kirchoff's law in an AC RLC circuit

Homework Statement I have the following RLC circuit with an sinusoidal voltage generator and I want to verify the Kirchoff's first law with an oscilloscope. To measure the peak voltage in each of the components I just permute the positions between the component and the resistor. The question...
30. ### Hi, can somebody explain this RLC circuit to me?

Hello to everbody can you help me how come C6 to be 10p and c5 13.5 and and l1 to be 190n and L6 240n i start with 100Meghz, with one circuits 50/XL or 50/XC now become three different thanks i understand the first circuit, i understand the second circuit, but now they make three circuits how...
31. ### For a damped RLC circuit, why must R be small?

Homework Statement I'm reading the textbook section covering damped series RLC circuits (provided below). I'm wondering why the author stipulates "When R is small..." Homework Equations Given above. The Attempt at a Solution Given above. Any gentle and courteous comments are welcome!
32. ### Engineering What is the Time Constant for an RLC Circuit?

Homework Statement Homework Equations I know for RL circuit T = L/R For RC circuit it is RC But how to go ahead for RLC circuit.The Attempt at a Solution I calculated for RL as 1/4 = 0.25 And RC as 1 Then I added both time constant and got 1.25 Book answer is 0.5. How to solve this? In...
33. ### Engineering Impulse Response of an RLC Circuit

I bolded the portions I need help with. 1. Homework Statement A series circuit consists of a resistor with a resistance of 16 ohms, an inductor with inductance of 2 H, and a capacitor with a capacitance of 0.02 F. At time t = 0 there is no charge on the capacitor and no current in the circuit...
34. ### Engineering Finding Current in a Parallel RLC Circuit

Homework Statement Find io for t≥0. Express your answer in terms of t, where t is in milliseconds. There is no energy stored in the circuit in (Figure 1) when the switch is closed at t = 0. Homework Equations ##x(t)=x_f+[B_1cos(ω_dt)+B_2sin(ω_dt)]e^{-αt}## The Attempt at a Solution Let...
35. ### Engineering Underdamped Parallel RLC Circuit

Hey guys, so I'm having trouble with this circuit analysis question. I need to find voltage across the capacitor as a function of time. I nearly finished analyzing but I'm having trouble solving for the initial value constants in the voltage equation. So first I used KCL to create the equation...
36. W

### RLC Circuits - Q Factor and Amplitude

Homework Statement Imagine you have two RLC circuits you are trying to scan for resonances. They have identical resonant frequencies, but circuit 1 has a very high Q-factor (Q1 >> 1), and circuit 2 has a very low Q-factor (Q2 < 1). Let's assume you are already on resonance and looking at V(out)...
37. ### Calculating Currents & Voltages of an RLC Circuit

Homework Statement An RLC circuit contains the following components in series: a 15Ω resistor, a 200μF capacitor, and a 12mH inductor. What are the currents and voltages through each component? It's known that the current through the resistor is 1.75A⋅cos(250πt) Homework Equations χL=ω*L...
38. ### Engineering Problem with series RLC circuit and dependent source

Homework Statement here is my problem : Homework Equations like usual, the problem is related with RLC circuits and transients The Attempt at a Solution [/B] from here, the solution is obviously wrong because from the solution, its alpha should be -300 and not -0.4...and from the...
39. ### Solve RLC Circuit Problem Homework

Homework Statement http://imgur.com/a/3xSYb Homework Equations RLC equations: q= Qmax e ^ -Rt/2L cos wd t wd = [ 1/LC - (R/2L)^2] ^ 1/2 The Attempt at a Solution So, I am trying using Kirchoff law, but not sure what the question asks. I thought it may be a trick and after a long...
40. ### Finding the average energy in an RLC circuit

Homework Statement Homework Equations Q(t) = Aei(wt+Φ); dQ/dt = i*w*Q(t); E = (L/2)(dQ/dt)2 + Q2/2C i = √-1 E above is average energy The Attempt at a Solution When I plug in Q(t) & dQ/dt into equation above (E) I get: A2L/2(w02-w2)cos[2(wt+Φ)] w02 = 1/LC After I plugged both of them in...
41. ### RLC Circuit DC Homework Solution

Homework Statement Homework Equations The Attempt at a Solution I used the loop rule where ##ΣΔV=0## and junction rule. From here I get 4 equations ##i_3=i_1+i_2## ##ε-i_3R_3-i_1R_1-L(di\dt)=0## ##ε-i_3R_3-i_2R_2-Q\C=0##...
42. ### Engineering Question about free source RLC circuit

Homework Statement below is my question : Homework Equations all of the equatios used to solve this problems are equations for free source RLC circuit. The Attempt at a Solution so far i have solved problem (a), whose answer is -1400V/s, the problem is when i want to solve (b) and (c) do...
43. ### Plotting a RLC Circuit: Analyzing a Differential Equation

I'm not sure about the physical behavior of a RLC circuit and I have to give a presentation that involves one. So I've decided to plot the current. I found a book that gives a differential equation to describe the circuit. ##L\frac{d^2i}{dt^2} + R\frac{di}{dt} + \frac{1}{C}i = \frac{dv}{dt}##...
44. ### How to solve the differential equation for driven series RLC circuit?

Homework Statement It is the driven series RLC circuit. It is given in the following images. It is from the section 12.3 in this note. Homework Equations The differential equation, as given by 12.3.3, is ##L \frac{d^2 Q}{d t^2} + R \frac{d Q}{d t} + \frac{Q}{C} = V_0 \sin{(\omega t)}##...
45. ### Alternating RLC circuit with an additional capacitor

Homework Statement http://imgur.com/a/TOUjV part b, specifically finding the maximum charge for C1. The question that boggles me is whether Imax changes on the left side of the circuit, after the switch closes. Homework Equations V=IR Xc = 1/(wC) XL = wL The Attempt at a Solution I was able...
46. ### RLC Circuit lab equipment problem

Hello all, I am a lab technician for a university and I am having some problem with some lab equipment. We are doing an RLC circuit lab with a frequency generator, oscilloscope, decade resistance box, capacitance box, and inductor. The equipment is connected in series, except for the...
47. ### Engineering Can the RLC Circuit Homework be Solved Using Different Methods?

Homework Statement R = 125 ohms, L = 200 mH, C = 5 uF, initial current in L is -0.3A, and initial voltage across C is 25V. Homework Equations v(t) = (Bcos(wt)+Csin(wt))e^(-at) The Attempt at a Solution I've solved for v(t) t>0 and got 25e^(-800t)(cos(600t)+ (4/3)sin(600t)). The second...
48. ### RLC Circuit Behavior with Changing Frequency, Capacitance, and Voltage

Homework Statement In the tuned circuit below, what will happen to the reading of the ammeter when: a) source frequency increases. The voltage is constant b) the capacitance increases. The voltage and source frequency are constant c) The voltage increases. Source frequency is constant...
49. ### Polarity of capacitor/inductor in RLC circuit

Homework Statement In the figure given, the switch was at position A for a long time, at time =0 the switch is turned to position B... My question is how do we assume the polarities for both the resistor and the capacitor after the switch is in position B Homework Equations ?? The Attempt at...
50. ### RLC Circuit with a Gyrator as an Inductor

Hi, Im trying to build a resonant circuit with a ~low frequency resonance (<1kHz). I am using a Gyrator (https://en.wikipedia.org/wiki/Gyrator#Application:_a_simulated_inductor) as the inductor. Im using: RL = 100ohm R = 27kohm C = 1uF I put another 1uF capacitor in front of Zin, to form a...