Phase Definition and 1000 Threads

Can someone explain a little of the physics behind 'phases' I can't get a grasp on what is actually happening. Current - I can understand that electrons are moving. Voltage - okay, no problem different charge here than over there. But then you throw in phases...and stuff is cancelling...

Ok so i have the equation y'=y^2(y-3)(y-5)^3 I found the equilibrium positions to be y=0, y=3, y=5. For my phase diagram all the arrows are pointing up so the solutions are nodes? The last part asks Describe the long term behavior of the solution to the above differential equation with...

http://i59.tinypic.com/727ole.jpg My answers http://i59.tinypic.com/mkzvqp.jpg Can some see if I am going in the right direction, thanks.

In an RC circuit, the phase angle between the input and output voltages (not current and voltage) seems to be proportional to the amplitude of the output voltage. That is, as the phase angle between input and output goes to plus or minus 90 degrees, the output voltage goes to 0. Why is that?

So a phase transition occurs when a system may minimize its free energy by spontanously breaking some symmetry. At least that is what I have learned from my current course so far. However I also did another course concerning phase transitions. In this case phase transitions were always...

Homework Statement Given that you have found the following transfer function for a circuit, H(jω), what is the phase at very low frequencies? (jωRC-ω2LC)/((1-ω2LC) + jωRC) a:∏ b:-∏/2 c:+∏/2 d:0 The Attempt at a Solution I understand that the phase angle is ψ=arc tan(img(ω)/real(ω))...

Homework Statement A Nyquist (polar) plot of a standard second-order system is shown below (drawn to scale). Suppose a unit-step function is applied as the input to this system. Determine the peak percentage overshoot expected in the system output. Homework Equations The Attempt at a...

What is the difference between "Gas Phase Ion Chemistry" and "Plasma Chemistry"? If one wants to learn about the ionization and dissociation processes of hydrogen gas are either of theses fields appropriate to study?

Homework Statement Understanding the bode plot for, G(s) = \frac{1}{2s-1} Homework Equations The Attempt at a Solution Usually when I am drawing bode plots for either real poles or zeros, I simply solve for the break frequency knowing that a zero/pole will give me a +/-20dB/decade asymptote...

Hi, I'm trying to figure out what phase differences take place with an ideal transformer. This is what I have figured out so far: If you apply an AC current to the primary coil then you will get an alternating flux in the primary and secondary coils simultaneously therefore the fluxes are in...

The following LPP was asked to solve by two phase method Max z=5x+3y subject to 3x+5y<=15 5x+2y<=10 x,y>=0 I have applied Two phase method only in the presence of artificial variables. But in the given problem we need no artificial variable. How to proceed to solve it by two phase method?

How can I measure the phase angle between two signals of the same frequency without an oscilloscope? Thanks in advance

Hi, I found out this paper http://www.pha.jhu.edu/~javalab/pendula/pendula.files/users/olegt/pendulum.pdf with this animation http://www.pha.jhu.edu/~javalab/pendula/pendula.files/users/olegt/pendula.html At first there is written there, that the area of possible states in some range...

Hello experts! Help needed. I got a relay manual for translation and one of the items there is "Phase Differential". The context is as follows: "These settings program the differential element when the differential feature is in use. This feature consists of three instantaneous overcurrent...

i need to know what pressure oxygen will liquefy at under various pressures but i can't find a phase diagram anywhere any link phase diagram that shows pressures 0-50 atm would be useful

3 Phase Rotor / Stator Swapping ? I have been toying around with the following idea : (specific application project) Normally a stator is the external housing of a motor and is fixed to a structure - the rotor is the shaft through the middle of this stator etc. and is rotating at ...x... RPM...

Hello, I am in need of big help here. I don't know what else should be done to get this correct. I have to build this PLL circuit and choose any 3 N (integer) of the N-divider. Then I have to observe the input signal Sig_in and the output signal VCO_out for each N. The result should be that the...

What exactly is phase space and how is it different from real space i.e. 3 co-ordinate system? what does it mean when someone says "dynamics occurs in phase space"? I'm very new to all this so pls take that into account to

I read in my Chemistry workbook that: "At higher temperatures, vapour pressure increases as more energy is provided to the liquid molecules, allowing them to escape into the gas phase." At the boiling point, all energy is gone into breaking bonds and to convert liquid phase molecules into...

I understand this is probably a very stupid question to some of the people on here, but none the less i would still like to know. It hasn't been explained very well to me. I have a vague understanding that it is a number that you collect for each possible path? Please correct/elaborate on this...

I had a question regarding some text in a paper that I was reading. It had to do with ramsey interferometry, where they initialized a particle in spin up (lets say up along the z axis on the bloch sphere), after which they applied a pi/2 pulse to rotate it 90 degrees around the x-axis, they wait...

Dear All, I have a question about the optical properties of light in a metal. I need to solve a problem. Homework Statement a] Why is the phase shift in a metal neither 0 or pi? b] And calculate the phase shift of gold with a wavelength of 514 nm? n_real=0,5 and n_imaginary=1,85...

Hi guys, I was hoping someone may be able to clear something up for me. I have been reading a paper on Quantum decoherence and was curious about what particular point (it could easily just be me misunderstanding) It is commonly noted that the superposition of waves represents all of the...

Phase modulation is a system in which the amplitude of the modulated carrier is kept constant, while its phase and rate of phase change are varied by the modulating signal. By the definition of phase modulation, the amount by which the carrier phase is varied from its unmodulated value, called...

what is difference between coherent and non-coherent detection? and what is a PLL? secondly what is meant by 2*pi phase rotation? is it same as 2*pi phase shift? thanks in advance

What is phase shift of qpsk when symbol change occurs ? Can anybody explain please ?

Hello, I was wondering, suppose I had a mixture of a few liquids that were immiscible, say 4. Now, when calculating the degrees of freedom, I am confused about the number of phases. I think the number of components is 4, but the number of phases should be 1, liquid, right? Or does each...

Homework Statement How would the state change graph of some matter undergoing deposition look like? 2. The attempt at a solution I would assume that since it is undergoing deposition, it would just be a slope from the gaseous state to the liquid state. However I am not sure of this...

Homework Statement If the phase of vibrating sources was changed so that they were vibrating completely out of phase, what effect would this have on an interference pattern? Homework Equations n/a The Attempt at a Solution This question undermines my understanding of...

Greetings to ALL. tonequester here. I am re-doing my first, and LONG post. Concerning an electric guitar. Strings resonate at say, 800Hz. Wooden neck and body have their own resonant frequency, so I am told. No two guitars resonate at the same frequency, as no two, complex, combinations of...

Hi all, I have recently come across term "phase wand between the magnetron and the accelerator, to provide reflected power from the accelerator to the magnetron to adjust the magnetron frequency to match the resonance frequency of the accelerator. this basicallly used in Medical Linear...

Homework Statement I hope this question is better suited to this forum... (See picture) We have 3 areas in which a wave can move. The wave Y1 starts at area 1 and goes towards Border 1, some part of it is passed to Area 2. That part goes towards Border 2, and some part of it is reflected...

Homework Statement (See picture) We have 3 areas in which a wave can move. The wave Y1 starts at area 1 and goes towards Border 1, some part of it is passed to Area 2. That part goes towards Border 2, and some part of it is reflected back into Area 2. That part moves towards Border 1...

Homework Statement I have an AC RLC circuit with the inductor in series with parallel capacitor and resistor. At what w is the emf in phase with the current? Homework Equations The Attempt at a Solution I'm suppose to know this from a previous class but as a transfer student...

Homework Statement Say you have a small boat moving through water, and creating a short wave-group which is a superposition of waves in the range of 0.2m-2m. If the shore 50meters away, how long will it take the fastest of the wave-components to reach shore? {assume the depth is constantly very...

Homework Statement Describe how the Fraunhofer diffraction pattern of a grating depends on: (a) the spacing between the grating lines; (b) the overall extent of the grating; (c) the amplitude distribution over an individual line; (d) the phase distribution over an individual line. A...

I'm working on an assignment due next Thursday and I'm having a little bit of difficulty on two problems that seemed surprisingly easy on the surface. My difficulty lies primarily in making sure I understand what the problems are asking. Here are the problems and I'll detail my idea without...

Hello, I am trying to figure out the transfer function for an RC phase shifter: http://imgur.com/2dnRYn7 (Picture of circuit) I am not sure how to calculate the output and specifically the phase of the output of this circuit. I understand that I need to consider one of the 'golden rules'...

Homework Statement The other day in lecture my professor mentioned the words mode locking and phase matching (same as velocity matching apparently) while on the topics of lasers. However, i can't find anything that can provide a simple explanation of what they are. Is there anyone who would...

I have three elements, A, B, C, that under certain conditions (rapid heating and cooling) form one ABC phase solid. Sometimes when I add a fourth element, D, I get two phase (AB,CD) solid. Obviously this phenomena is thermodynamically favourable. My guess (still undergraduate) is that there...

I have trouble understanding how to draw phase portraits. Is there a good pedagogical overview of their basics (such as elliptical vs hyperbolic orbits, separatrices etc.), along with an algorithmic way of how to draw them when it is not easy/possible to find v(x)? Basically something explaining...

I'm making a system with PLL. Here's more or less a principal scheme. What happens here is that the signal in this compensating system becomes really low and phase detector might not work properly. What I want to ask, what type or how to make a phase detector which can detect phase correctly...

Homework Statement https://scontent-b-dfw.xx.fbcdn.net/hphotos-prn1/v/1012733_10201076259690370_236735593_n.jpg?oh=4896ca67a34d3b223b764aba8ed308ab&oe=528A1B57 Homework Equations http://upload.wikimedia.org/wikipedia/commons/3/34/Phase-diag2.svg The Attempt at a Solution Not sure entirely...

Homework Statement There is a solid that can be in two phases, with energies U1(S,V) = S2/a1 + b1V(V-2Vo) and U2(S,V) = S2/a2 + b2V(V-2Vo). Consider a phase transition between the two phases at zero pressure. At what temperature, T0, does it occur? Homework Equations T = ∂G/∂S...

In an LCR circuit (circuit with inductor, capacitor and resistor), are the following statements always true? The capacitor voltage always lags the resistor voltage by a phase difference of 90°. The inductor voltage always leads the resistor voltage by a phase difference of 90°. The current...

I have no idea how to do this or where to start. Can someone please help me? Problem 4.4- Suppose n o and n e are given. In (a) you only need to find the magnitude of the group velocity. Problem #2 in HW 10 may be helpful. You can also directly use the definition of group velocity, i.e., v g =...

Hi, I've been reading a lot today about waves and how they have both a phase velocity and a group velocity. The group velocity makes perfect sense to me, I would phrase it as the speed at which the wave is propagating. The phase velocity on the other hand is quite confusing to me. What exactly...

Homework Statement A step down transformer, 2400/240 V, 50Hz has the following resistance and leakage parameters. Z1 = R1 + jX1 = 4 + j12 Ω Z2 = R2 + jX2 = 0.04 + j0.12 Ω The transformer is operating at 80% of its rated load. The power factor of the load is 0.866 leading. Determine the...

Hi guys I have been testing a brand new 250kw 3 motor wired in delta. I have it connected to a 170 amp vfd with no load for testing. It draws 105 amps at 50hz and is balanced. Intermittently the motor makes a strange that i have not heard before. It sounds like a spoon taping another...

Hello Homework Statement I have this tab http://img18.imageshack.us/img18/3317/eyph.png Anf I have to find the group and phase velocities for a wavelength λ=550nm Homework Equations v(phase)= c/n v(group)=dw/dk v(phase)*v(group)=c²/n² The Attempt at a Solution I don't know...