What is Sources: Definition and 537 Discussions

A tertiary source is an index or textual consolidation of primary and secondary sources. Some tertiary sources can be used as an aid to find other sources. The exact definition of tertiary varies by academic field.
Academic research standards generally do not accept tertiary sources as citations.

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  1. B

    Engineering AC Circuit with Dependent Voltage and Current Sources

    I have trouble solving the following problem. Am I supposed to start by doing nodal analysis on the loop on the right. Can someone give me a start. Thanks...
  2. R

    Confusion with Nodal Analysis w/ Sources

    Hi , I'm currently stuck on a problem that requires to be solved with nodal analysis. I'm confused to what signs should I use when there's a voltage source in the loop. The problem: I already know the answer from the solutions but what I found is at V_0 : (V0 - 60V)/12 + V0/12 + (V0...
  3. avito009

    How Does the Big Bang Contribute to Matter Creation?

    One of the sources of matter creation is pair production when 2 gamma ray photons collide and produce electron positron pair. The other would be Quantum Fluctuations which create again electron-positron pairs. What are the other methods of matter creation other than the above two?
  4. A

    Triple-slit experiment with 2 identical sources

    See the setup in the picture. There are 2 sources who each emit a particle at the same time. And there are 3 slits, such that the particle from source1 can go through slits1&2 and the particle from source2 can go through slits2&3. There is a detector at the common slit, so slit2. The particles...
  5. Rectifier

    Circuits - Node analysis of connected and dependent sources

    Hey! I have a problem with the theory side of this circuit here: 1. The problem I know that you are supposed to pick the buttom node of the circuit to represent your significant node at which you shouldn't construct a series of equations. But what if I picked another node as my significant node...
  6. A

    Network -- RC network with sources

    Homework Statement The current Ix and Vx in the below circuit are The Attempt at a Solution Volt at node A= V. Applying KCL at node A, V/5+ ((V-20) /10) -7=0, 3V =90, V=30.
  7. D

    Engineering Elementary Linear Circuits - Dependent Sources

    Homework Statement the problem is a circuit analysis. I can try to make the circuit but the image i created shows all the resistors and voltage sources. imgurl Find i,v,is,vs Homework Equations \sumloop vi=0 \sumnode ij=0 The Attempt at a Solution I can not make a...
  8. neilparker62

    Exploring 16.4 GHz Radio Sources and Its Implications in Radio Astronomy

    Hi Just wondering if 16.4 GHz (or so) is a commonly encountered frequency in radio astronomy ? Because I'm theorising a possible secondary photon emission following photon emission and electron recoil in the Hydrogen 1s - 2s transition.
  9. marcus

    Deformation quantization (survey, introduction, sources)

    In case anyone is interested in DQ I came across this, which is moderately accessible in parts. http://math.berkeley.edu/~alanw/242papers99/karaali.pdf Evidently Alan Weinstein (Berkeley faculty) was teaching a graduate course Math 242 back in 1999 and put this online for his students. If...
  10. S

    Calorimetry quantifying sources of error

    Homework Statement I am conducting an experiment to determine the specific heat of a certain metal using a typical calorimetry experiment (using a polystyrene cup). I have been asked to list sources of error and quantify them in relation to the total error in the experiment - I have thought...
  11. C

    The Einstein Maxwell Action with sources

    The free field Einstein-Maxwell action is often states as $$S[A, g] = - \frac{1}{4}\int_M F^{\mu \nu} F_{\mu \nu}d^4 x + \int_M R(M) d^4x$$ where ##M## is the spacetime manifold ##F## is the field strength and ##R(M)## is the curvature of the spacetime manifold as dictated by the metric tensor...
  12. B

    Wind and rain sounds -- how to make from basic sources?

    ok I have a FFT filter ( lowpass and highpass), white, brown, and pink noise generators. How do I use all these things to make wind ,rain, and ocean noise ? I am told there is a way.
  13. R

    Linear regression, sources for this wikipedia link

    I really like the derivations here http://en.wikipedia.org/wiki/Proofs_involving_ordinary_least_squares Could some one recommend a good book for them. I'm tired of googling these equations every time I want to use them. Thanks!
  14. S

    Double pipe heat exchanger sources

    hi I am looking for a complete double pipe heat exchanger thermal and mechanical design. I've found some online sources like this http://scopewe.com/double-pipe-heat-exchanger-design-part-1/ tutorial. and book like process heat transfer by Kern. but I need newer books or online sources. thanks...
  15. C

    Diamond Circuit, Three EMF Sources -- Parallel?

    Hi, Is the circuit in the attached image essentially one with three parallel branches, each with a different source of emf and two resistors? ie, ε1, R1, R2 on one branch, ε2, R3, R4 on another, and similarly for the last one? Thanks!
  16. G

    Can you explain voltage sources in series and parallel completely?

    i would like to know the underlying reasoning why it works the way it does and how it works based on the explanation given by the book Electricity Demystified, but i would like a far better explanation. Give me something like an analogy to better explain it physically. In there it says: for...
  17. Dotini

    Most Recent Changes in Earth's Magnetic Field; Sources Analyzed

    http://www.sciencedaily.com/releases/2014/06/140620115751.htm http://www.esa.int/Our_Activities/Observing_the_Earth/Swarm/Swarm_reveals_Earth_s_changing_magnetism The first set of high-resolution results from ESA's three-satellite Swarm constellation reveals the most recent changes in the...
  18. H

    Electric Field Sources & Sinks: Definition

    Positive charges are sometimes called "sources" and negative charges are called "sinks" of electric field . How can one define this terminology..??
  19. J

    Can an ODE accurately model an RLC circuit with additional sources?

    The equation for this physical model is: http://upload.wikimedia.org/wikipedia/commons/f/fb/RLC_series_circuit_v1.svg And for this is: http://upload.wikimedia.org/wikipedia/commons/d/d0/RLC_parallel_circuit_v1.svg But and if now I add a source of current in those schemes, the...
  20. J

    Equating Voltage/Current of Associated Sources: A Comprehensive Guide

    How equate the voltage/current of the associated sources with the voltage/current equivalent?
  21. Rugile

    Electrodynamics problem (circuit with two sources)

    Homework Statement In the circuit (see attachment) we have 2 sources. If we decrease the EMF of the first source (ε1) by 1.5V, the current changes in every branch of the circuit. How does the EMF of the source ε2 has to be changed, so that the current through the ε1 source would be the same...
  22. J

    Dependent vs. Indepenent sources?

    Dependent vs. Indepenent sources!??... Can anyone give any insight into why you can't treat dependent sources as open circuits (dependent current sources), and why you can't treat dependent voltage sources as short circuits (dependent voltage sources)? I understand why it is the case for...
  23. Avatrin

    Kirchoff's loop rule with multiple voltage sources

    Hi Let's look at this: The issue I am having is that while I know that this is accurate: I just cannot wrap my head around why. I1 is a result of both voltage sources. So, while the equations clearly tell me that the voltage drop across the resistor R1 is I1R1, I cannot wrap my...
  24. B

    Good sources of information regarding S-parameters

    Hello all, I am wondering if anyone can point me in the direction of any good material that explains s-parameters. So far, I have encountered explanations that just confuse with no effort put into simplifying the concept. Even my lecturer assumes that the entire class are geniuses. I don't mind...
  25. D

    Data analysis - Comparing temperature data from multiple sources

    Data analysis -- Comparing temperature data from multiple sources Dear Peter, I am Engineering student from Japan.I have installed 8 sensors,4 at rural and 4 at urban area.Those sensors measures the temperature and other property in time series format.Now, I am using one month data and...
  26. S

    Engineering Electric circuits-2 sources (batteries)

    Homework Statement http://prntscr.com/3cmnbx Va=20V R1=3kilo ohm R2=9kilo ohm R3=6kilo ohm R4=7kilo ohm Vb=5V It asks for the electric current for every resistance(R1-R4) Homework Equations The Attempt at a Solution To be honest the thing i want most is to ask some questions rather that...
  27. M

    Circuit problems with capacitors and parallel emf sources

    I have quite a few questions so I've attached the associated images instead of making multiple threads. I'll share my attempts/reasoning for the problems and please tell me if my logic is flawed or if I am doing something completely wrong. Question 41: Bulb brightness is related to power...
  28. J

    Different way of calculating power factor from multiple sources

    Hi, I did a lot of googling and tried to search every forum I could, but I didn't quite found what I was looking for. Sorry if this has been asked before, english isn't my first language so there's a chance that I used wrong words to search for this question. Also I'm not sure if you use...
  29. S

    Measuring Etendue of LED sources

    How does one measure the etendue experimentally (when the area of the emitter and the angular distribution is not provided) in order to compare the focusing strength of two LED sources in an optical setup? Thanks!
  30. L

    Current in a Circuit with Multiple Voltage Sources

    What exactly are the rules for conserving the currents in a circuit? If we have multiple emfs in parallel with each other, how can we figure out the direction and magnitude of currents in each segment of a circuit? It makes perfect sense to me for one emf, and for the most part with two I...
  31. mesa

    Need sources to search for gamma function infinite series identities.

    I have a hard time believing we only have the limited number of series I have seen so far especially considering how much broader mathematics is than I had thought just a short while ago. Where should I search to find more infinite series summations for the gamma function? For example which...
  32. PinguZaide

    Engineering Mesh law in a resistor circuit with current and voltage sources

    Hello everyone. Hope somebody can help. Homework Statement We are given the following circuit. http://puu.sh/70uaQ.png We need to find the currents i1, i2 and i3 by explicitly using the mesh law. Homework Equations There are no relevant equations.The Attempt at a Solution So, I draw these 4...
  33. R

    Supermesh analysis w/ dependent sources

    Homework Statement Use mesh analysis to find the power delivered by the current-controlled voltage source in the circuit in the Figure: http://i.imgur.com/LUXYFO5.jpg Homework Equations 1 super mesh equation, 1 source equation, 1 mesh equation, KVL The Attempt at a Solution To start off, I...
  34. D

    Engineering Finding a voltage in a circuit with only resistors and current sources

    Homework Statement Find V0 in the circuit. Homework Equations Kirchhoff's Current Law: All currents entering a node must sum to zero. Kirchhoff's Voltage Law: All voltages around a loop must sum to zero. The Attempt at a Solution So far, I have taken the top of the center branch...
  35. B

    Modifying the heat equation for multiple sources

    If I have a hot wire, the distribution of its temperature with respect to radius (from the center of the wire) and time follows the heat/diffusion equation. However, now consider two wires, or even an array of many such wires. Say we can ignore the z coordinate and treat them as a point...
  36. kandrew

    Determining Voltage in Parallel Current Source Circuit | Homework Solution

    Homework Statement Determine the voltage v in the circuit after first replacing the three sources with a single equivalent source. Homework Equations v=iR The Attempt at a Solution I've arrived at the correct answer. I just want to make sure I did it correctly and didn't just get...
  37. L

    Impact of Helium 3 from Extraterrestrial Sources

    Can bringing a surplus of Helium 3 from a Extraterrestrial source effect our Earth's ecological balance? Has there been any studies on this?
  38. A

    Do current sources stack with current?

    Consider the following circuit: Now imagine that I add a 3A current source: Is the following equation correct? $$I_1=I_0+3$$
  39. M

    Engineering Finding Vy in a Circuit with Dependent Sources

    Homework Statement Determine Vy in the circuit of the below figure: (In attachment) Homework Equations ohms law resistance adding equations for parallel and series The Attempt at a Solution So I found Vx=(1.2A)(5ohms) = 6v Afterwards I computed the current supplier: (6)(0.1)=0.6...
  40. A

    Zin of a circuit with independent sources

    Hi, This is not a homework question. I need to calculate input impedance for a LNA and this is part of it. How do you calculate input impedance, Zin, for the circuit below? I tried by applying an input voltage, V1, and calculate Iin. Input impedance will be V1/Iin. However, the expression...
  41. N

    Two current sources in series with a resistor.

    hello, forum members. I'm new so pardon if any error. IS the question in this pic solved correctly.
  42. C

    Fossil energy sources on a young Earth-like planet

    I'm curious which kind of fossil energy sources could one find on a young Earth-like planet which is in its equivalent of Cambrian era. Yes, I understand it's clearly too early for mining carbon. So presumably peat instead, right? What about oil or natural gas? (EDIT: including more exotic...
  43. K

    Wave sources vibrating out of phase (destructive/constructive)

    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...
  44. A

    Rectifier and parallel ac sources

    I am new to engineering so i might not understand the concept well , but i want an ac source to provide current only in one way , so i can connect them in parallel. I have 2 AC sources one with a 100 V output and one with a 120 V output , i need to connect them in parallel so i can get a 220 V...
  45. C

    ScienceDaily News & Other Similar Physics Sources

    "ScienceDaily News" & Other Similar Physics Sources I'm retired and a little out of touch - no technical library. I subscribe to the free emails from ScienceDaily News on Quantum Physics News. It's an excellent source with links to advanced research especially in areas of photon...
  46. S

    Direction of secondary wavefronts from the point sources

    Homework Statement My question is simple. Homework Equations Why do we not take the direction of secondary wavefronts from the point sources to be going backwards to the original direction of the wave as a whole? The Attempt at a Solution Thanks to you! :D
  47. B

    About lighting strikes and sources

    Hello everyone. I would like to know why we simulate in programs like atp lighting strikes with current sources and not with voltage sources. Could anyone help? Thank you :)
  48. T

    Question about radioactive sources

    Hi there, I have a few closed radioactive sources (Cs137, Pb210, Na22) that I am trying to use for a project but I am not that knowledgeable about them. Their activity is shown on the source but I'm unsure if this is related to the amount ie grams of substance inside the sealed container...
  49. C

    Distance from sources of different intensity to get same loudness

    Homework Statement A point source of sound emits energy equally in all directions at a constant rate and a person 8m from the source listens. After a while, the intensity of the source is halved. If the person wishes the sound to seem as loud as before, how far should he be now from the...
  50. B

    Calculating physical separation of 2 sources at unknown angle.

    I am doing a small project on Gamma Ray Bursts. I am looking at a data set of around a dozen bursts which are observed at an angular offset from their host galaxies (My theory is that they are in dwarf galaxies orbiting the host galaxy). Say the average separation of these GRBs is 4...
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