Phase Definition and 1000 Threads

hello, I have 3 signals in the form of sampled values. When I plot them using plot (t,vPa,t,vPb,t,vPc) where vPa, vPb, vPc contains the values and t contains the sampling istants I get this: when I calculate phase shift using fft I get phase angle = 0. I have tried using my own code ( which...

Hi guys, I have few questions here regarding power supplies. I have two models of power supplies and from the data sheet of the power supplies. and I would like to enquiry on one of the model. If i have to feed the load(Panel switchgear) fully 30/60V DC, 120Amp continuously for several hours...

Is it possible for a group velocity of any wave disturbance to be greater than its component phase velocities?

Consider the following; We have Earth with two moons in orbit (discounting the existence of our own moon for the sake of this hypothetical scenario). One moon is the size and mass of Pluto, orbiting around 70,000km from Earth. The other is the size and mass of Pluto's moon, Charon, orbiting...

Homework Statement This is Problem 7.6 from Electronic Properties of Engineering Materials by Livingston. "Over a wide range of frequencies, the dielectric constant of a polymer is found to be proportional to the inverse square root of frequency. (a) How does the phase velocity of EM-waves...

Homework Statement Homework Equations None. The Attempt at a Solution This is the final part of a past exam question. I've got through the first parts and can (thanks to a separate question I asked here) read the phase diagrams and find melting points etc. However now it's asking for...

THIS HOMEWORK WAS PLACED INCORRECTLY IN ANOTHER FORUM, SO THERE IS NO TEMPLATE (AND NO EFFORT) I have no idea how to tackle this. Please show me how to do these problems.

Homework Statement I was given a graph with two waves on it, the input and output wave. I found the frequency of the waves, change in magnitude and change in phase. The last question asks me to write the transformation from input to output as a phasor and he gave the relevant equation below...

Homework Statement Homework Equations None required? The Attempt at a Solution I understand that Id would be a disordered phase, Io an ordered phase and the other two are regions where 2 phases exist at the same time possible due to cholestrol. I am assuming so means solid ordered. But...

Thanks

Homework Statement In an earlier part of the question, I derived the temperature dependence of the latent heat of vapourisation of a liquid as dL/dT=L/T+ΔCp-L/Vvap(∂Vvap/∂T)p I am asked to find the condition that upon expanding the gas adiabatically, we get condensation to occur, by considering...

Homework Statement A mass-spring system with a natural frequency of 3.6 Hz is started in motion with an initial displacement from equilibrium of 6.1 cm and an initial velocity of 0.7 m/s. What is the value of ϕ? (Question aside: Finding the amplitude of the resulting function?) Homework...

Currently learning about Statistical Mechanics and just wanted to check my understanding. Am I right in saying that a point in phase space is just a specific microstate of the system?

I'm reading the EM waves chapter on Griffiths, and, after getting the complex amplitudes of the reflected and transmitted waves he obtains the real amplitudes by (apparently) just "disregarding" the exponential part, which is equivalent to assuming that the phase of both waves is equal to the...

At the superconductor-superconductor point contact regime, two Andreev bound states carries supercurrent through the S-weak links-S interface. According to literature, current can be simply expressd Eq1) I_S=(1/Phi_0)*dE_A/d Phi here I_S : supercurrent, Phi_0 = flux quantum, E_A : Andreev bound...

Hello, I'm currently studying for an exam and came across a question I can't seem to figure out. How exactly do we go about calculating the phase of a frequency response. Here is the question, it for part A) iii. Here are the answers to the other parts and the sketch of the magnitude: I know...

The mean velocity of a wavepacket given by the general wavefunction: \Psi(x,t)=\frac{1}{\sqrt{2\pi}}\int dk A(k)e^{i(k x - \omega(k) t)}, can be expressed in two ways. First, we have that it's the time derivative of the mean position (i.e., its mean group velocity): \frac{d \langle...

I am in the section of Gibbs Energy for my chemistry course and in the textbook it says the system is at equilibrium at the boiling point, so deltaG=0, and deltaH=TdeltaS. I was just wondering if the system is always at equilibrium during any phase change, not just at its boiling point. Thanks!

Homework Statement The circuit above has a 29 resistor and a 11.1 mH inductor. Calculate the theoretical phase difference between the current CPA and voltage VPB if the circuit is driven by a sinusoidal voltage source with a peak amplitude of 3.5 V at the following frequencies: 20 Hz 420 Hz...

I intend designing a 3 phase AC generator. Thereafter I need to build it. Believing in "a picture tells a 1000 words", I am very much a "pictures" person, and as my studies in the electrical field were completed many moons ago, the formulas are now "forgotten" - so thus I want to approach this...

Its always said that a reflected light ray acquires a phase shift equal to ## \pi ## if ## n_1 < n_2 ##. But considering the Fresnel coefficients, its revealed that its only for the s-polarization reflection coefficient that ## n_1 < n_2 ## causes the coefficient become negative. The...

Homework Statement For a double pendulum, how do we plot the phase space for ##\theta_2## (the lower of the pendulum), i.e. the plot ##\theta_2, \ \dot{\theta}_2?## ##x## = horizontal position of pendulum mass ##y## = vertical position of pendulum mass ##\theta## = angle of pendulum (0 =...

Today, I made the following question at Physics SE, but the community redirected me here In short, I have made a proof for EF/MF phase difference near an oscilating dipole that "vanishes" far away from the dipole. So, what I am asking for is a proof verification. The physics SE post...

Homework Statement A body oscillates with simple harmonic motion along the x-axis. Its displacement varies with time according to the equation x = 5sin(pi*t + pi/3). The phase (in rad) of the motion at t = 2s is a) (7pi)/3 b) pi/3 c) pi d) (5pi)/3 e) 2pi Homework EquationsThe Attempt at...

Is there a relationship between amplitude and phase response of a realizable filter? For the purpose of ease, let us consider only a FIR digital filter. I would like to design a FIR digital filter with a given frequency response (amplitude and phase responses given as a function of frequency)...

Up to this point I have got a grasp of some basics of "steepest descent method" to evaluate the integral of a complex exponential function ##f(z) = \exp(A(x,y))\exp(iB(x,y))##. Using this method the original integration path is modified in such a way that it passes through its saddle points...

Homework Statement Please see attachment for circuit and parameters. Homework Equations i --> 90 phase angle for inductor so Z of inductor = 0.5<90 sum of voltages = 0 #<40 = #*cos(40) + i*sin(40)*# The Attempt at a Solution shteii01 - 100 + 0.5<90 + V2<theta = 0 --> 100 + 0.5*cos(90) +...

Hopefully I can word this correctly. Consider viewing S11 of a short on a smith chart. It starts at the left and moves clockwise around the edge. If you then add a small length of line between the reference plane and the short, the phase angle wraps further around the outside in the clockwise...

Homework Statement An inductive load is connected to a 120V (rms), 60Hz AC source. The load draws 5.0 kW at a power factor of 0.81 (lagging). You need to improve your power factor to 0.96 (lagging) by adding a capacitor. What is the Capacitance needed (in uF)? Homework Equations P/|S| =...

Homework Statement A mass m = 750 g is connected to a spring with spring constant k = 1.5 N/m. At t = 0 the mass is set into simple harmonic motion (no damping) with the initial conditions represented by the point P in the phase space diagram at the right. **(This phase space diagram has...

Hello, I am watching this video to try and better understand Gibb's Phase rule The part of interest starts at 4:30 I like that he is using a visual to explain, which is very helpful. When there is 1 phase and one component, there are 2 degrees of freedom. This means two variables can be...

Homework Statement http://i.imgur.com/u8vUv5a.jpg Find the phase constant. Homework Equations x(t)=Acos(ωt + Φ) v(t)=-Aωsin(ωt + Φ) Vmax = ωA ω=2π/T The Attempt at a Solution ω = 2π/12 = 0.5236 A = 60/0.5236 = 114.59 cm v(0) = -30 = -114.59(0.5236)sinΦ 0.5 = sinΦ Φ = π/6 and 5π/6. Which...

Homework Statement http://i.imgur.com/TZcJkjH.jpg Find the phase constant Homework Equations x(t) = Acos(wt + Φ) x(t) = Asin(wt + Φ) w = 2pi/T The Attempt at a Solution I see A = 20cm. T = 4s. f = 1/4 = 0.25Hz. w = 2pi/4 = 1.57Hz. 10 = 20cosΦ 0.5 = cosΦ Φ = π/3, 5.24?

Hi everyone,1. Homework Statement Three inductors with 0.1 H each are delta connected to three phase ac newtork with 220V/50Hz. Determine Iph, IL, P, Q and Theta. Homework Equations Showed at the attempt. The Attempt at a Solution [/B] XL=2*pi*f*L=31.4 ohms Iph=Uph/XL=220/31.4=7 A...

Hi, If the voltage, full load current and full load output power (kW) of a 3 phase induction motor are known, and the efficiency is assumed to be 90% (is this realistic), am I correct in thinking that the full load power factor can be approximated (due to assumed and not actual efficiency) as...

Hi, I need to calculate the voltage regulation of the 3 ph Dzn transformer. I have knowledge of the current going into the primary winding of the transformer (Delta winding) and hence need to calculate the current in the secondary (load current) so that I can use this in the voltage...

Hi, Is there a difference in efficiency between a three phase motor and a single phase motor, in terms of power in against power out. If so, could you please explain why one is more efficient than the other. The reason I ask is because I'm researching the development of the induction motor for...

I have several questions about poles and towers. a. Does all of transmission towers carries three-phase powers? Is there no transmission towers designated for single-phase? b. Does all towers are for transmission purposes only? Is there any towers in the world used for distribution instead of...

Homework Statement A short circuit test is performed on a small single phase transformer. The results are: Primary Voltage 5V, 60Hz Primary Current 2A Secondary Current 10A Primary Power 8W a) Making suitable approximations deduce the primary/secondary turns ratio (single number)? b) Making...

Why are electric and magnetic fields in an electromagnetic wave in phase? Can somebody please explain that?

Are there any chemicals that are liquid under high pressure (above 1 atmospheres) but solid when exposed to low pressures (below 1 atmosphere)? Are there any chemicals that have a similar reverse phase transition at any pressure with the solid extending down to vacuum?

Hello everyone! :) I am studying for an honours course in Statistical Physics. I have stumbled upon the book "Statistical Mechanics of Phase Transitions" by J.M. Yeomans. The layout of the book, as well as information, is exactly what I need. I want to work through the problems and was...

Hello Guys, I was wondering what will happen if the battery pack of my Honda civic hybrid dies (dies = malfunctions, stops working completely things like that) ? Moreover I wanted to know if the IMA/PDU can be removed (not used) to thus convert the engine into the a typical gasoline engine ...

hello! why capacitors and inductors affect the phase of both current and voltage of a AC circuit and resistors don't? let's say we have an AC circuit with resistors only, then there is no change in the voltage and current as imposed from the voltage/current source, right? but what happens...

Homework Statement For a bridge rectifier (4 thyristor) feeding an RL load having infinite inductance (to assume constant current) and a 100 ohm resistance, calculate for firing angles of 90°, 120° & 150° the average DC voltage and current. The bridge supply is 200V RMS. Draw Waveforms of...

Hi, For a single phase full wave fully controlled bridge rectifier carrying a RL load, how is the RMS voltage and current calculated? I have researched textbooks but can only seem to find RMS equations for Resistive loads and I am not sure whether the negative load voltage will affect the...

we talk about three phase supply .. I want to know that what actually is three phase..?? Its obvious there are three wires carrying current but what is "phase" ? Is there something like, transmission line is further divided into three wires ..?? Please explain..its quite basic.. and I am...

In the given figures , what does the arrows denote , I mean what direction ?? VnR is upward in 1st fig. , VnR is towards left in 2nd fig. ( n is neutral here ) while in 3rd the line voltages are in anti-clockwise direction..! I wanted to know the pupose of this and why these directions only??

There are two waves y1=a. sin(ω.t) & y2=a. sin(ω.t + φ) My question is what is the phase difference of these two waves? Is it "φ" or "φ/ω"?

Sorry for such a simple question but where do we model the energy going during phase transitions? If I had a mercury thermometer in a pot of water, and I had a 200 degree Celsius heat reservoir in contact with the water, I would see the water temp hold steady during the phase transition...