Source Definition and 1000 Threads

Homework Statement How do i find the equivalent voltage source of... 1) Two AC voltage sources in series with same frequency and phase = ? 2) One AC voltage source in series with a DC voltage source = ? Homework Equations Equation of a AC voltage source as a function of time V(t)=V_m *...

why we take current source as a open and voltage source as a short in superposition theorem. is this is because of its internal resistance or any other reason exist?

Hi all , is it possible to use the source transformation for dependent source ..? i guess yes because i came across a problem which asks to use source transformation to find Vx as shown : http://img571.imageshack.us/img571/2389/50111057.jpg and my solution was ...

Homework Statement Why does a transistor with a constant V_{B} (e.g. V_{B}=1V) only need V_{C} \approx 0.3V to act as a current source; If V_{C} < V_{B} doesn't that mean the transistor is not in forward active mode and thus not a mode we want to work in. Homework Equations The...

In GR normal stresses as per the three lower diagonal terms T11, T22, T33 in the SET (stress-energy tensor) (e.g. http://en.wikipedia.org/wiki/Stress%E2%80%93energy_tensor) are source terms for gravitating mass. And afaik true for any similar theories of gravity. Owing to their being resolved...

Here's my current project goal ( And what I need help with): I want to use an LED light source, shine it through a 1" x 2" slit and then use a linear array camera to detect the edges of the slit. The problem: Since LEDs are a point source of light emission, my camera has a difficult time...

I had not heard of this, so I thought others might be interested. I thought that all natural Anti matter had been lost at the beginning of the Universe, but apparently there is a 10000 light year cloud of anti matter near the center of our galaxy...

Catching up on the Universe Today I came across this article discussing the history of the wow signal. Since it fit the profile of a non-naturally generated signal, the would indicate either an equipment glitch or there really was something out there sending a signal. My question is, based on...

Hello! I'm a long time reader, but this is the first time I've not been able to find the information I've needed already... I have a small electromagnet that needs to have an AC current (it is essential that the electromagnet has a reversing polarity) but the source of power comes from a 6v...

Hi all, I have a question with regards to why should we use an ac-dc, dc -dc, dc-ac converter to an ac drive? Why not connect an ac source through a transformer directly to the ac drive? Isn't it the same? What equations can prove that the use of converter is a better choice?

Hi everyone, I currently stumped in the process of approaching a dependent voltage source problem using node voltages. Attached is the circuit. What I know: the Node north of the 60V supply with also be 60V there are four nodes, two when supernodes are used What I'm confused...

I am looking for a schematic diagram of a compact, temperature compensated, stabilized, high precision (accuracy within 0.5% or less) current source. The target current should be easily set to 100/150 mA, no matter if discrete or integrated solutions must be used. This project will be...

Is it physically possible that the entire universe and everything in it, in a form of a Wave, emitted from a source? That the Big Bang wasn't the point of all creation, but only our universe getting pulsated from a source. And what we see as expansion really could be the Wave (or pulse?) being...

Circuit help Homework Statement I have a book problem that show this pic (see attachment) The problem wants me to calculate Vo and the end point of the graph and midpoint but I am not sure what Vo is. Homework Equations Vo=Va-Vb The Attempt at a Solution I think Vo is the total...

Homework Statement There is a perfectly absorbing spherical shell with radius R1 suspended in space. Inside is a smaller spherical shell with radius R2. Inside that shell is a ball of radius R3. All three objects are concentric. In the center of the ball is a point source radiation with power...

Homework Statement A tiny vibrating source sends waves uniformly in all directions. An area of 3.25 cm2 on a sphere of radius 2.50 m centered on the source receives energy at a rate of 4.20 J/s. (a) What is the intensity of the waves at 2.50 m from the source? (b) What is the intensity of...

how to find power factor of the load, the three voltmeter readings are V1=220v,V2=122v,V3=136v

Hello everyone, Can anyone suggest me a suitable GUI programming language for windows (like Microsoft VB or anything else). The software should be free of cost. It also should not restrict me to publish my product as freeware/open source. (Additionally the software should be able to handle...

Homework Statement if i have source separation between 2 light sources, d, and wavelength, λ, what is the highest order node and antinode? Homework Equations The Attempt at a Solution im not sure where to start for this question I am leaning towards division to cancel out the meters

Challenge! Use Taylor series expansions to prove first-order Differential Equation Suppose dy/dt = f(y) has an equilibrium point at y = y0 and a) f'(y0) = 0, f''(y0) = 0, and f'''(y0) > 0: Is yo a source, a sink, or a node? b) f'(y0) = 0, f''(y0) = 0, and f'''(y0) < 0: Is yo a source, a sink...

It's strange no one has noticed but after reading through the Mathjax documentation guide, all you have to do to view the source code is right click over any Mathjax image and click "Show Source". A new window will pop up with the Latex code. Jameson EDIT: Try it here $ \displaystyle...

Forgive the title, I was unsure of how to briefly describe the problem. Attached are diagrams. Homework Statement The device shown in Figure P2.5 can be modeled as a current source in parallel with a resistance. When this device is connected to a 5[mA] current source, so that...

When professors are insufficient or don't teach very well, is Khan Academy a good alternative to learning topics such as calculus/differential equations, etc. as well as the sciences (bio, chem, physics)? I can't tell if the content is good resource material because I'm not an expert on any of...

Mean Value property (harmonic functions) with a source?? Homework Statement I understand that the heat equation may yield ∂u/∂t=0 on the LHS and on the RHS we may still have Uxx+Q where Uxx is partial with respect to x twice and Q is a heat source. U in our case may be the temperature...

Homework Statement One microphone is located at the origin, and a second microphone is located on the +y-axis. The microphones are separated by a distance of D= 1.21m. A source of sound is located on the +x-axis, its distance from microphones 1 and 2 being L1 and L2, respectively. The speed of...

1. Homework Statement Find the total charge on a circular disc of radius ρ = a if the charge density is given by ρs = ρs0 (e^−ρ) sin2 φ C/m2 where ρs0 is a constant. Are the two limits of integration from 0 -> a for ρ and 0->2∏ for φ? In the example given in the notes, ρ varies, instead of...

Homework Statement i attached the problem. I am unsure how to solve this problem. I applied KVL and got 15-1I-2vx-vx-2I=0. Where I is the current in the circuit. From that equation I have 2 unknowns, so I obviously have to find I. To find I I'd have to find Req, but I don't know how the...

Homework Statement Determine the power generated by the dependent source in the circuit shown below: Homework Equations Ix=V/R Pgen=V*I The Attempt at a Solution I made an equivalent circuit, but it may not be correct (resistors in parallel?): Ix=-(12V/(12/7)Ω)=-7A 2Ix=2(-7a)=-14A...

I'm working on a project that has a 7.4v rechargeable battery pack and I am going to recharge the pack with a solar cell. If the solar cell is only capable of outputing no more than about 2v, is it at all possible to charge the battery pack? Thanks!

learning C++ by reading the code of open source projects? Is there any resource that teaches C++ by taking an open source project (at the level of quake 3 for example)and explains the code step by step for some one who only knows the very basics . In my opinion It will be very efficient . I can...

Hi, I am confused about my solutions to the following governing equation: u_{tt}-c^2u_{xx}=F_{xx} For F=A(x)sech^2\left(\frac{x-c_gt}{B}\right) Where c,c_g,B \in \mathbb{R} and A(x) is a linear function. Also, we have c_g<c. Substituting physical values for the parameters, I...

http://www.openvsp.org/

Hello, I am not an electrical engineer but I do have a slight background in some electrical engineering concepts. My question is a general one about relays (more specifically solid state relays but I don't think that really changes my question). I understand that a relay gets a small input...

Hello forum, a battery is a voltage source: it provides constant voltage, regardless of the load connected to it. there is also a current source: it provides constant current, regardless of the connected load. Is there something like a power source, something that outputs constant...

All stars and Galaxies appear to give off the whole spectrum of electromagnetic radiation. If one views images of the distribution of background radiation in detail it appears to be filimetary in nature. Also if one views the distribution of visible matter in the universe it also appears...

Homework Statement Upon using Thomas Young's double slit experiment to obtain measurements, the following data was obtained. Use this data to determine the wavelength of light being used to create the interference pattern. DO this in 3 different ways! The Angle to the Eighth maximum is 1.12...

I am looking for some intuition into a way of looking at the Gauss curvature on a surface that describes it as the divergence of a potential function - at least locally. I am not sure exactly what the intuition is - but this way of looking at things seems suggestive. Any insight is welcome. In...

hi, 1. could somebody explain me in very simple terms what are sourcing / sinking I/O. 2. In which cases i have to think about these things while interfacing. 3. i did lot of browsing and studied but every time i get confused, suggest me a simple lab experiment so that i can do each of...

I need a constant current source ckt which can source current in the range of 0.1 to 1mA, with +/-1% tolerance, with Vcc 3.3v Any ideas? I found this - http://www.ecircuitcenter.com/Circuits_Audio_Amp/BJT%20Current_Source/BJT_Current_Source.htm But no info on tolerance. What happens to Io...

Not sure which section to post this in, but here goes. It's entirely my own words - might look like homework but it's for electronics. Multiple microphones are connected to a computer. A sudden sound, like a gunshot, goes off in the distance. These microphones are separated from each other by a...

Methane from natural gas could be a great source of energy (eg. in thermoelectric plants), but the need to curb CO2 emissions stands in the way. I wonder whether one could get useful energy from some partial combustion reaction of CH4, that yields H2O plus some carbon-containing solid that...

When I first encountered the term genetic mutation, I envisioned a gene that had somehow spoiled – like an orange with mole on it. A little research indicated that a gene is a linear string of amino acids that codes for a protein. The term mutant gene was being used to indicate a gene in...

I am stuck with this problem,the dependent current source is creating a big problem for me, please help. I have attached the problem.

What is the root source of "Light"? I'm not talking about converted/transformed energy via external sources, i.e. Electricity or heat transformed to Light. Whats the root source? Energy itself?

Homework Statement P15. The police car with its 300 Hz siren is moving toward a warehouse at 30 m/s, intending to crash through the door. What frequency does the driver of the police car hear reflected from the warehouse? (5 marks) Homework Equations doppler shift for an approaching...

Hi, This is a question regarding my employment. A centrifugal pump at the source tank sends fluid 200m using 3" hoses to a recieval tank. When the automatic valve shuts on the recieval tank the pump stops due to it having a pressure sensor.When the pump stops there is 8 Bar pressure on...

What would be the best way to produce 2,000 volts at a low amperage using 12V as the power source? I guess I just want to produce 2000 volts at a low amperage in a mobile environment?

hi all, I'm looking for a cheap (and by extension simple) circuit. i have a special pot (Piher's 10mm hex PT-10) that can't be changed. the pots can be physically changed but i have to use this type. the series has a 150mw power rating, with resistances of ...

Homework Statement I wasn't sure what section to post this in, but for my honors lab, i need to cite sources on values or theories that i include in my lab report like normal. Yet I'm having trouble finding a decent source for the speed of light and the index of refraction of air. I...

How much experimental evidence is there that the speed of light stays c between a source and target moving wrt to each other?