# Questions tagged [laplace-transform]

Questions regarding or involving Laplace Transforms with respect to Electrical Engineering.

159 questions
Filter by
Sorted by
Tagged with
33 views

### Calculating steady state output using Laplace transform

I've tried to obtain the the steady state output with the help of final value theorem and multiplication properties of Laplace transform.But I'm not sure whether I've solved the problem correctly or ...
157 views

### Inconsistency in Values of Laplace Transformed Current when Changing Units

I was trying to convert the units of the following current in Time Domain and Complex Frequency domain (s-domain): $$i(t)=20\cdot e^{-t}H(t)\,\,\,\,\,\text{[mA,ms]}$$ Where $\text{[mA, ms]}$ ...
106 views

### Transfer Function Derivation

Where did the following transfer function come from? $H(s) = -H_o\frac{\frac{\omega_o}{Q}s}{s^2 +\frac{\omega_o}{Q}s + \omega_o^2}$ $H_o$ is the gain at resonant frequency. I'm told it ...
52 views

### How to determine the transient response of a circuit to causal periodic inputs?

As you know, analyzing a circuit with phasors provides only the steady-state response, and is only useful for sinusoidal signals and DC signals. Fourier series allow us to analyse a circuit with ...
79 views

### If I look at a signal in its frequency domain, are there some guidelines by which I can tell how that signal looks in the time domain?

I was studying the Laplace transform and the Fourier transform, and I can't figure out if there is some intuitive way of finding out how a signal looks in the time domain if we know its frequency ...
84 views

### Laplace Transforms and the imaginary input

When we get an exponential on the RHS of our differential equation (or if we give an exponential input) it's quite easy to solve the equation, but if we provide a sinsusoidal or cosinusoidal input, ...
49 views

### How to do Transient analysis?

Consider the above example earlier I used to form a differential equation and then do its solution using Laplace,but for this example the differential equation comes out to be non-ordinary. Please ...
56 views

### How to calculate damping ratio and natural frequency of a high order system?

To calculate the rate of damping and the natural frequency of second-order systems is easy, third order as well. How do I calculate the damping rate, natural frequency, overshoot for systems of order ...
56 views

### Phase, Frequency and Laplace transform

I have a doubt on the relationship between phase and frequency. We know that the definition of angular frequency is: ω(t) = d($phi$(t) / dt, where $phi$(t) is the istantaneous phase of our ...
46 views

### How do I refer the transfer function of a system from its Laplace equivalent?

I have a problem, I know how to analyze circuits in Laplace domain to get the transfer Laplace function. However, I don't know how to translate the answer to "real life" Suppose that I have a ...
58 views

### Phasors and Fourier Transform

I have always been told that for a sinusoidal variable (for instance a voltage signal), the fourier transform coincides with the phasor definition, and this is the reason why the analysis of ...
79 views

### Is the following op-amp-circuit-in-the-Laplace-domain analysis correct?

I am relatively new to analyze circuits in the Laplace domain. So I decided to solve some problems as an exercise. Below presented a problem and my solution to it and I have two questions: ...
40 views

### AC signal analysis: Voltage dip (amplitude dip) at time = 0

I'm working on a series RLC problem where the input voltage is a sinusoidal function for all time. The catch is, for t < 0, the sinusoidal function is of greater magnitude than t >= 0. There is no ...
94 views

### Solving capacitor voltage with Laplace

I saw this example and I got confused. The example shows: $V_{C}(s)=\dfrac{R\parallel\frac{1}{sC}}{sL+R\parallel\frac{1}{sC}}V_{in}(s)$ . Isn't it enough to express $V_{C}(s)$ with the voltage ...
58 views

### What is difference between natural response and zero-input response of a system and how to find natural response?

In most books it is said that natural response is another name to zero-input response while in some resources is is mentioned that the classification is based on poles of transfer function and input....
71 views

87 views

### How to tackle circuit containing time variable resistor?

simulate this circuit – Schematic created using CircuitLab For instance above schematic find current as function of time in circuit above I studied it about months before and am not able to ...
56 views

92 views

### Why inverse of time delay is non causal

Please explain the following statement "If $P(s)$ contains a time delay term, $P^{-1}(s)$ is non-causal". Here '$s$' is Laplace variable. Can someone please explain the reason of non causality?
105 views

### Combining two ideal voltage sources with an impedance between them

Solving a problem, I came across the following source transformation:        My question is: I know that I can do the following:       &...
222 views

### Degenerate circuit concept and its theoretical and practical implications

I came across with the term "degenerate circuit" when I was studying solving linear differential equations with Laplace transform. I have learned that a system is called degenerate when the ...
453 views

### Laplace transforms for transient analysis

simulate this circuit – Schematic created using CircuitLab For t<0 the switch is opened. Att=0 the switch is closed. ...
245 views

### How to get the transfer function of electrical network using nodal method

We have the following circuit: I am trying to get the transfer function using the Mesh Method. The first equation I've got is: (s+1) I1(s) - sI2(s) = Vi(s) The ...
260 views

### Why do we use Laplace transforms to analyse transient circuits?

I just learned transient circuits and we solved them both in the time domain and the Laplace domain and I can't understand why we would use the Laplace domain as it seems it is a lot more simple to ...
179 views

### How do I calculate the current in this circuit using Laplace transforms, with a time shift?

In this exercise I have to calculate i(t) and the switch occurs when t=0.01 s, I tried doing it using Laplace but I always get the wrong answer. I did an exercise that is exactly like this one except ...
93 views

253 views

### Determine by the order of transfer function what kind of filter

How can I determine by looking at the following tranfer function, that is this the transfer function of a band-pass filter: $$\frac{1}{as^3+bs^2+cs+1}$$
162 views

### Equations governing the impedance of a generalised constant-phase element in the time domain?

I apologize in advance for the large wall of text, but I feel like to properly ask this question, some background information is in order. I've been recently working on modelling the impedance of a ...
107 views

### How do I compensate for Exponential decay in an op-amp circuit

Using an oscillator, I want to provide a square wave input to the second opamp circuit shown in this TI application note (but using IC741 instead.) The problem lies in the s domain: I get a voltage ...
123 views

### Algebraic way for finding a transfer function of a filter

I've the following filter and I tried to write the transfer function for it: simulate this circuit – Schematic created using CircuitLab And I wrote for the current nodes the following ...