# Questions tagged [laplace-transform]

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

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### ROC of Laplace Transform of a time shifted impulse signal

If x(t) is of finite duration and is absolutely integrable, then the ROC is the entire s-plane. This is stated and proved formally in the book of signals and systems by Oppenheim in the context of ...
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### Unilateral laplace transform of rect(t/2)

What would be the unilateral laplace transform of rect(t/2)? We know that rect(t/2) can be written as u(t+1)-u(t-1).So what would be its unilateral laplace transform? Should it be (exp(s)/s)-(exp(-s)/...
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### How can I do inverse Laplace of this transfer function to get the step response of the RLC circuit?

I have found this to be my transfer function for the circuit. I have tried doing partial fraction decomposition, but I end up with an s on top which I don't understand what to do with.
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### How to compute Vgs(t) for circuit below?

Does anyone know how to compute the Laplace and inverse Laplace transform to find vgs(t) for turn on transient for circuit below? Zener diode is of 6.1V.
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### How to derive Laplace and Inverse Laplace equation for RCD level shifter for SiC MOSFET?

Does anyone know how to get Equation 7 from Equation 5 and 6, shown in the picture? Or any other method for the circuit analysis on getting Eqn 7? Attached also the schematic diagram of the process ...
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### Nyquist stability criterion in discrete time domain

I've been transforming systems from the s-domain to the z-domain, and looking at the Nyquist plots I get in the z-domain. So far I've assumed that the Nyquist stability criterion that applies in the s-...
82 views

### Electrical network transfer function

I am trying to solve this problem, and my answer is wrong. I suspect that I messed up the Laplace transform of the voltage source. However, I saw this in the book and thought I could simply use it. ...
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### How to find driving point impedance of non-inverting op-amp circuit

I have this circuit: And I am asked to find the driving point impedance. I know that a driving-point impedance relates the voltage and current at a pair of terminals. The formula for the driving-...
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### What is the best method for solving this circuit analysis problem in the S-domain?

I'm just curious what the best method for solving for voltage across the capacitor might be. My initial idea was to use nodal analysis but I ran into a roadblock in that I am not entirely sure how the ...
91 views

### laplace- second order

We were told to solve this using the series equivalent circuit for the inductor and the parallel equivalent circuit for the capacitor. However, I am not sure how that will look like. Could someone ...
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### Inverse Laplace transform

I found the transfer function of the RC circuit (Figure 1). $$G(s)=\frac{V_{out}(s)}{I_{in}(s)}=\frac{R_2}{R_2sC_1+1}=\frac{50}{50*10^{-9}s+1}$$ I can check if the transfer function is correct or ...
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1 vote
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### What is the correct way of replacing the value of a step voltage source in Laplace?

I'll be presenting two ways to reach the same answer. I would like to hear which way is the correct way to get there. I am not interested in the result, it's the same in both cases, I'm interested in ...
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1 vote
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### Matlab calculation with laplace analysis is different from what I got in LTspice

Here is the circuit diagram. Waveform for the current passing through voltage source. The code I use for Matlab . ...
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### Colpitts oscillator with a series inductance π-network

In a Colpitts oscillator, the feedback occurs via a series inductance π-network. An, based on a common-emitter BJT amplifier, is shown in the circuit below. Here below is a simplified version. This ...
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### Differential equation from a circuit: two methods give different results

I saw an example problem from a lecture note and tried to solve it by a different method. Then I got confused as the results are different. Here is the example: It's not some web site as I know so I'...
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### Rewriting piecewise voltage function using Heaviside?

Recently I've had an idea to create an assignment where we have low-pass filter connected to the voltage source which is described by piecewise function. I've already dealt with periodic functions ...
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### Laplace transform for circuit analysis gives me different result from LTSpice Simulation

Here is a simple circuit I want to simulate with LTSpice. I make everything to be 1 for easy arithmetic. The source is $$V_1 = cos(t) u(t)$$ $$H(s) = \frac{R} {R + \frac{1} {s C} + s L}$$ Substitute ...
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1 vote
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### Why the ROC is all s? (Signals & System)

The problem from mit ocw signals and systems (open for everyone) https://ocw.mit.edu/courses/6-003-signals-and-systems-fall-2011/ Sorry, I tried to write it Latex, but it doesn't work well. Sorry that ...
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### How to prove property of transfer function for causal LTI system

For causal linear time-invariant systems the degree of denominator must be larger or equal than the degree of the numerator. How can this be proven rigorously?
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### How to solve this problem using transient time-domain analysis?

Find V0(t) in this circuit assuming zero initial conditions. I solved it (refer image above) using frequency-domain analysis using Laplace and found the answer, but I am not able to get the same ...
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1 vote