Recent content by Rob K

Thank you Sorphiecentaur, I checked it and that is indeed the case. I was using the standard circuit as shown on the datasheet for a 555, and where there is the voltage divider, I have a 22 Kohm resistor and a 10 Kohm pot and a What I didn't know was that in this circuit, to the pot there...

Tried that, I only get the voltage, no frequency

Hi there, I have built an InfraRed beacon using a 555 timer using a 10K pot to tune the circuit. How can I test that it is pulsing at the required 38kHz frequency that I need. I have tried using an oscilloscope, by connecting up the Earth and probing one of the legs of the IR LED, but I...

Thank you, this gives me something I can now work with. I may be back if I get lost.

Also just to clarify, could this now be written thus: \begin{align*} f(s) = \frac{1}{a^2}(1-e^{-at}\ -\ a\ te^{-at})\qquad &\Leftrightarrow \qquad F(s) = \frac{1}{s(s+a)} - \frac{1}{(s+a)^2} \end{align*} Kind regards Rob K p.s Just learned LaTeX through this post, thanks.

Thank you very much, what you have written is very clear. I was very curious of the answer, I saw that it was the transform of what you are referring to as H(s), my only conclusion was that there was a technique of ignoring a term that we had not been previously taught, but that did not seem...

Ah, this is the answer that my lecturer gave in the notes. I just assumed it to be the right answer, but to be honest. Is it wrong?

Homework Statement f(t) = (1/(a^2))(1-e^-at - ate^-at) Homework Equations f(t) = (1/a)(1-e^(-at)) F(s) = 1/s(s+a) f(t) = t e^(-at) F(s) = 1/(s+a)^2 The Attempt at a Solution F(s) = (1/s(s+a^2)) - (1/(s+a)^2)Totally lost now, but I think this is wrong anyway, can anyone help me please. I...

Brilliant, after an evening of studying the intuition of complex numbers, this now makes a little bit of sense to me. Thank you very much antiphon. I a may be back for a little more, but this is good for me to be going on with. Kind regards Rob K

Good day to you people, I have just started learning control theory at Uni, as part of my course, and I have to admit it is quite difficult to grasp. I am starting from the basics, and I am having difficulty understanding what 's' is supposed to represent as regards the Laplace transform...

Hi, I was just wondering, as I find matrices fascinating, I don't know why, but I was wondering if there was ever a use for 3D ones and if so what would be their application? It just occurred to me as I was reading about holographic hard disc storage. Curiously Rob K

Apologies, I missed the comment about the rational root test. I don't know it, but now I know what it is called, I can learn it, thank you. After some reading I didn't realize that this is actually a fairly complex problem to do manually. I assumed as quadratics are easily solved by either...

Actually, I am working out an eigenvalue problem hence the Lamdas. I was kind of expecting to find a way to do this algebraically. If there were an x2 or λ2 term in there, I would be able to do it, but the lack of it has stumped me.

Hi guys, Need some help on something I didn't know I didn't know. How do you factorize this? -λ3+7λ+6=0 I assumed this? -λ(λ2-7) + 6 = 0 λ = 6 λ = ±√7 But that's wrong as the answers in the book are -2, -1, and 3. Can someone give me a little guidance on this, I have only...

This is insane, I am trying to revise the inverse of matrices and this one element is being really stubborn, please help. Here is the matrix 3 -1 7 2 0 1 5 -2 6 I have transposed it 3 2 5 -1 0 -2 7 1 6 Now as for replacing the element of...