Recent content by Terocamo

Oh I get it, with III(f) having a period of 1/T, the Fourier series should write: $$\frac{1}{T}\sum_{n=-\infty}^\infty\delta(f-\frac{n}{T})=\sum_{k=-\infty}^\infty c_k\cdot e^{i2\pi kfT}\cdots\cdots[4]$$ $$c_k= T\cdot\int_{0}^{1/T} \sum_{n=-\infty}^\infty\delta(f-\frac{n}{T}) \cdot e^{-i2\pi...

I came across a page which brings me a whole new of perspective towards Dirac Delta. I shouldn't have treated Dirac Delta simply like a function but, as you said, a distribution. It is then clear to me that the "value" of Dirac Delta itself doesn't seems to be important and that the integral is...

With Dirac Comb is defined as follow: $$III(t)=\sum_{n=-\infty}^\infty\delta(t-nT)$$ Fourier Transform from t domain to frequency domain can be obtained by: $$F(f)=\int_{-\infty}^{\infty}f(t)\cdot e^{-i2\pi ft}dt$$ I wonder why directly apply the above equation does not work for the Dirac Comb...

I have recently digged up a post in the forum about a confusion arise from definition of Dirac Delta function and I am actually really bothered by it (link to the thread). When people talk about sampling some function f(x) with Dirac Comb, or impulse train, they would be talking about the...

Can you illustrate a bit more about the induced charge? Why can't the induced charge change when the distance between the inducing charge and the induced charge varies? In fact, this is the point i can't get through i guess. You see, the influence of fields is usually stronger when closer, so...

It was told many times by my teacher that a disconnected metal plate and an earthed metal plate, forming a capacitor, will have the same charge regardless their seperation. I understand how the charge of the disconnected metal play remains unchanged, but I don't really understand how the...

But what if u touch that wire? It is said that u still will not receive a shock. I am thinking maybe a circuit that is not grounded does not form a closed circuit with the person touching it, there is no path for the current to flow back to the circuit do the person is not going to receive...

I understand that brass is an alloy of copper and zinc. If I want to eitch brass under standard condition, should I use iron III ions directly or use copper II first than us Fe III ion? I ask this because from the electric potential data, Fe metal will form under the presence of zinc if Fe...

We cannot define the absolute potential if there is no reference point, earthing a point is one way to define a zero point. Hence, if the circuit is not earthed, then there should be a non-zero potential in practically any point of the circuit. Well I hope this can make my question clearer.

I was reading about current electricity and some how I came across the idea that a circuit of no earthed point will not cause any electric shock. I wonder if it is right cause if it is, why do we need an Earth wire in our appliance. I am also suspicious because if the circuit is not earthed...

My true confusion is not about the direction of the velocity vector. It is about the phenomenon that the two equation give two very close but not the identical (which I think should be) regardless that there is no difference whether the source is moving or the observer is moving.

Fact is the equation is not the same. The apparent frequency of a moving source differs from the that of a moving observer. This is what I am puzzled by the two equation. To be more detail, the two equation is based on two different approach. For a moving source, the apparent wavelength...

I have just read about the principle of Doppler effect. However there is a point which seemed a bit tricky. According to the book, when the source of wave is moving the apparent frequency to a stationary observer is given by the equation: f'=true frequency*speed of wave/(speed of wave +...

In fact the phenomenon you mentioned is not something related to static electrons. That is named as a covalent charator of an ionic bond. However, this does not mean the electron is stationed between the ions, instead they are moving in a manner that no tools can determine it's position...

I imagine that arbitrary force can be any kind of force. Physical movement of a conductor is perhaps simular to the relative motion of free electrons in it.(just guessing XD) Therefore it is the mechanical force causing the imbalance of charge because electron have mass and hence, inertia. If...