Source Definition and 1000 Threads

Hi everyone. I'm working on getting together some notes on school maths and of course I'd like to include some diagrams. The usual stuff, graphs of things like parabolas, circle geometry, etc. But I'm also skint. So I'm looking for some open source programs that can do that, and they need to be...

Guys, this seems very trivial yet I can not come to the correct answer and I've searched everywhere. I am asked to find the node voltages using nodal analysis. The trouble is I don't know how to express a current in a brach between 2 unknown voltages where there is an independent current...

How can current source be implemented? I think the source of current is the battery itself (due to potential difference). Plus current source has its own symbol. If battery is the source of current then does current source refer to the battery?

Homework Statement A circuit problem and I think a picture could do a much better job than anything I could type. Picture should be attached below if I didn't screw it up. Homework Equations I'm allowed to use Ohm's Law, resistor series/parallel combinations, superposition, Thevenin's...

Homework Statement the voltage Vc in the figure is always equal to 2 Relevant equations The Attempt at a Solution From kirchhoffs law, -Vc+4+5=0 Vc=9 V will Vc always equal to 9 V or it will vary?

I wonder to know what would happen when we use two flashlight in a same direction. by doing so, do we extend the range of light? if so, does it mean if the lights cross each other in a point perpendicularly the range that the light can traverse is going to reduce ? I have been said that if we...

Homework Statement Find is of the circuit below Homework Equations i=V/R v1+v2+..=0 is=vs/Req The Attempt at a Solution Resistance of circuit as seen by source = 7kΩ 6V(source)/7kΩ(Req)=.857i My question is, how come i3 is also 0.857i? Shouldn't it be different since it just...

Homework Statement I'm doing a practice problem and I'm asked to find source voltage and source current of the circuit below. Homework Equations i=v/R i1+i2+i3..=0 (KCL) v1+v2+v3..=0(KVL) The Attempt at a Solution So I started by calculating the current for the 2kΩ resistor, which I...

Suppose I have a 10kW input. I want to divide the 10kW into two separate sources, like 1kW and 9kW. What can I do to separate the input into these different ratings?

http://en.wikipedia.org/wiki/Schr%C3%B6dinger's_cat I don't understand, if the radioactive source is put in there then of course the Geiger counter will detect radioactivity so we know the cat must be dead?

Hi I've tried to solve the following circuit using Kirchoff's laws but i get wrong results.I know that because I've got a different solution of the same excercise.I've attached the image.My question is what are the equations of Kirchoff's laws because I try this over 2 hours and I can't figure...

Hello I need a source to power ADSL router when the electric power would be cut for any reason because i need to keep my laptop that i use for work connected to the internet. I found this "Anker® 2nd Gen Astro Pro2 20000mAh 4-Port Aluminum Portable External Battery Charger with 9V/12V...

Hi all, first post on PF! I was just wondering if a motor that is specifically designed to generate the most friction possible would be useful for heating purposes. If it's just wishful thinking, feel free to say so and explain why. Thanks!

I am a freshman (ore med). My curriculum does not have physics until junior year of college. I want to take the MCAT at the beginning of junior year. I am reading the AP Physics textbook of my high school (I didn't actually take AP Physics, I just bought the textbook) and while I am learning a...

Some of my advanced chemistry students would like to try this pharmacokinetic model circuit outlined in an AAPT publication (Cock & Janssen, The Physics Teacher, Volume 51, Issue 8, pp. 482-484 (2013)). It is a simple RC circuit, but I've never built a constant current source and am unsure of...

ZapperZ submitted a new PF Insights post Why You Should Not Use Wikipedia As Your Primary Source Continue reading the Original PF Insights Post.

Homework Statement the observer is stationary , but the sound source is moving towards the observer , i was told that the speed of sound relative to the observer doesn't change. why is it so ? in my opinion, the speed of sound relative to observer changed . because of v= f x (lambda) , as...

I am studying thyrisors right now. I am really struck at trigger circuit . The book shows gate source voltage and gate chathode voltage as two different things. I fail to understand the difference and significance of them. Please help me out .

Hello! I am a bassist in a rock band and I hace slight issue with trying to rig up this "this" http://www.newegg.com/Product/Product.aspx?Item=N82E16811992011 LED Controller to do its color changing awesomeness while pulsating with what is coming out of an output on my amp (which is a...

How are constant current sources different than any other source? Also, would they really have a constant current in any situation? Even when back-emf is induced? Can anyone explain the use of a constant current source, and how different they are from other sources?

please delete this post Hello, Accidentally I have noticed a strange behaviour using two different magnets, which I would like to discuss. The picture shows a disc magnet (shown also in the right to see the magnetization) with it's N facing upwards. Onto the disc magnet N side, a cylinder...

Homework Statement In essence, I'm trying to make a model of how the heat from a point source diffuses through air. It should be a function of both distance and time (I'm assuming either a 1/r^2 or an exponential dependence on distance). Homework Equations I found this equation...

I found some open source code in wx that I'm considering re-writing in qt and adding some new functionality to. It's for science research. Before I do, I wanted some feedback from the community if this is a worth while endeavor and an estimate of how long it would take. It's about 700 lines...

Hi, I'm having a strangely hard time imagining how the distribution of particles would look around a constant point source in some scenarios. I came up wiith something that sounds reasonable to me, but would like a logic check. The easy one for me to grasp is distribution when the source...

Homework Statement A point source in water provides 10 W of heat for 10 seconds, and is then shut off. The surrounding water has a temperature of 20 °C. Provide the temperature profile as a function of distance r and time t. Homework Equations The Attempt at a Solution If it...

Ok so I recently read this article (http://www.extremetech.com/extreme/184280-focus-fusion-has-cheap-clean-earth-saving-fusion-power-been-right-under-our-noses-all-along). This gave me a few ideas and a few questions. I would like to create a smaller version of this setup to fuse deuterium into...

When a circuit is being alimented by AC this means that exist in the circuit a voltage source that is generating the AC or exist a current source that is generating the AC?

Hi everyone, I'm building a white light interferometer and need help choosing and finding a white light source. I'm using this mirau objective: http://www.edmundoptics.com/microscopy/infinity-corrected-objectives/nikon-interferometry-objectives/59312 Here is the setup: I know...

Which is the real interpretation for current source? Exist some device or electrical object that acts like a current source?

Hey all, I'm working on the JUICE mission (Jupiter Icy Moons Explorer) and I've been tasked with finding software (preferably open source, but paid is fine) that can optimize circuit network designs that I upload. Originally I was trying to find programs that would run optimization using the...

Hey guys, I have been trying to design a constant current source that has a digitally controllable (μcontroller) range of maximum current outputs. Ideally the source would be able to be adjusted from .25mA to 2mA. The input voltage for the source would be in the range of 9 to 14 volts. Also I...

I'm looking for the source for the QM interpretation of "shut up and calculate". I thought it was synonymous with the Bohm theory and that I had seen it in Shankar or Sakurai. Yes, I Googled it and found David Mermin, and some other dude named Tegmark that I'm won't to bring up lest I...

Homework Statement The problem - confirm that the amount of radiation measured from a source is related by inverse-square to the distance. Here is a graph of my data fitted to y = a1 * x^a2. Every point is an average of 3-8 measurements (as many as needed to have a statistical error of...

For this problem, I added in an external source, and found an expression for the external current in terms of ix. Then I divided Vex/iex to get the Rth. Then I did superposition to find the Vth. I had some troubles getting rid of the extra currents, particularly i3 and i2. I was wondering if...

Homework Statement Image Homework Equations Current divider The Attempt at a Solution The only thing I see is that I solve for R1 and R2 for t < 0. Other than that I'm confused and not even sure I'm right about solving t<0.

Hi Guys Could someone please point out where I'm going wrong with the following problem. If I place a magnet on a vertical surface such that the magnet must resit the force of gravity in order to hold itself in place, will this magnet stay in place forever? If it does why does this not...

Homework Statement Attached image Using node analysis: ix(0-) = (v-4)/10 + v/3 + v/5 = 0 v = 0.632 ix(0-) = -v/3 = -0.211 A I don't understand why they didn't use a current divider since there is a 5 ohm resistor in parallel with the 3 ohm. Current changes for resistors that...

I've attached the question that I am referring to. I believe I'm heading in the right direction with this one by stating that: 1/Rt = 1/(6+j8)Ω + 1/(9-j12)Ω But I am confusing myself with my algebra. Any help is appreciated

Homework Statement See images In the first image, I made a circuit with the switch closed and then two when the switch is opened. The bottom circuit is the Thev transform. Homework Equations The Attempt at a Solution Let me first explain my understanding of the circuit. Prior to t = 0, the...

Homework Statement Attached an image with the exact question. Homework Equations α = 1/2RC ω = 1/√(LC) α > ω i(t) = Aest + Bect The Attempt at a Solution (a) First I found ω and α ---- ω = 1.4*10^5 1.4*10^5 < 1/2RC → R > 357.1429 Is it safe to assume...

Good afternoon PhysicsForums! I have a design for a voltage controlled current source. I've included the circuit diagram. The basics of the design is that I have an AC voltage and a DC Voltage summed then passed through a 1MOhm resistor to give me a current on the order of 1 microAmp. This of...

Homework Statement An LRC series circuit with R = 200Ω , L = 31mH , and C = 1.8μF is powered by an ac voltage source of peak voltage V0 = 540V and frequency f = 550Hz. What are the peak voltages across the inductor, capacitor, and resistor and their phase angles relative to the source...

http://imageshack.com/a/img834/5921/7iap.jpg Homework Statement Consider the double slit pattern shown above where the distance between slits is d. Each lettered point is labeled according to ΔD, the difference in distances from the slits to that point. ΔD is expressed in terms of wavelength...

That 2 terminals shows PD of 1 volt on Meter, but when shorted, there is no current shown on Meter? I checked and rechecked [using different meters, wires, AC, DC options and what not], so I see only V measurement, but no I. Is it possible? If so, then what is the use of that PD, when we can't...

This is not schoolwork. Imagine that light did not have a constant speed, but behaved in the manner expected from experience. Namely, if the source of the light is rushing toward you, the light will approach you faster; if the source is rushing away from you, the light will approach you slower...

Does it matter if the resistor is on top or below a voltage source after doing a source transformation? According to this picture from wikipiedia, the resistor is on top of the voltage source: But even if the resistor (Z) was on the other side of the voltage source, it would still be...

This is not a homework. My physics training feels like having taken place in another life, so please show mercy :) I would like to know what´s the formula to calculate the temperature at a given distance from a candle. I found this: Thermal Conductivity = heat × distance / (area ×...

Homework Statement The WSFM radio station (which broadcasts at 101.7MHz) emits 1.78x10^29 photons per second and has an effective radiated power of 12kW. If the same number of photons were emitted as visible light, what would be the power of the light source? Homework Equations...

Homework Statement See Image Homework Equations Source Transforms The Attempt at a Solution After having simplified the positive terminal of the op amp, how is this calculated into the overall equation to find v(out)? Also, at the v(out) node, in what respect is the 370Ω resistor...

I found this constant current source circuit over at instructables.com. This circuit calls for 2N5088BU for Q1 and FQP50N06L for M1, but I replaced those parts with 2N2222 for Q1 and PHT6NQ10T for M1 because that's what I have on hand for simulation. I calculated R2 = 0.5/0.125 = 4 ohms, but in...