What is Source: Definition and 1000 Discussions

Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use the source code, design documents, or content of the product. It most commonly refers to the open-source model, in which open-source software or other products are released under an open-source license as part of the open-source-software movement. Use of the term originated with software, but has expanded beyond the software sector to cover other open content and forms of open collaboration.

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  1. H

    The Doppler Effect - Finding Velocity of Source

    Homework Statement A fire truck emitting a 450 Hz signal passes by a stationary detector. The difference in frequency measured by the detector is 58 Hz. If the speed of sound is 345 m/s, how fast is the fire truck moving? Homework Equations frequency of observer = (velocity of sound...
  2. K

    Internal resistance seen by the voltage source, Vx?

    Hi everyone, I have attached an image of the op-amp configuration (all op-amps are ideal). Basically, the question asks to calculate the resistance seen through the voltage source. The answer is 3 kΩ but I just don't understand how this is found. If someone could assist me, I would really...
  3. D

    Calculate Gate Source, Drain Current, and Source Voltage of a JFET

    Homework Statement Uploaded Homework Equations Uploaded The Attempt at a Solution So what I started with is Vg=(R2/(R1+R2))Vdd - 10 = -7 Volts this is incorrect though I was told it is -4 V what did I do
  4. |Glitch|

    What Makes ULX-1 in the Pinwheel Galaxy an Exceptional Black Hole?

    In the Pinwheel Galaxy (a.k.a. M101, NGC 5457), 20,870,000 light years away, there is an Ultra Luminous X-Ray source called ULX-1 (a.k.a. X-10) which has astronomers somewhat baffled. When they first observed M101 ULX-1 they observed that it was emitting 3.0 x 1039 ergs-1 in the soft x-ray...
  5. H

    Copenhagen Suborbitals open source space travel

    Very interesting bunch of guys trying to get a man into suborbit as cheap as possible. Found their website and youtube videos links at the bottom. Thought I would share. They have interesting video's of engine tests as they try to design the first rocket to send a man into space...
  6. C

    How to stabilize voltage on a mV scale using a DC power source?

    Hello, I'm in the process of calibrating a thermometer/datalogger (Omega DP470) that uses a thermocouple type T (-200-350 deg. C range), and I need a DC voltage source that can feed a steady voltage of 39.000 mV. I believe at this point I can either purchase a precision voltage source that...
  7. D

    MCNP planar source (rectangular)

    Hello to everybody, I need some explanation on how to use SDEF variables to define correctly a planar rectangular source. Let say this source is emitting in all direction but I am interested in a side of the source surface where a point detector is located. I used in my example VEC (VEC =001)...
  8. P

    Virtual source at the back of the mirror

    Homework Statement What is meant by this: "When mirroring a source in a plane mirror, it looks like the rebounding light rays come from a virtual source at the back of the mirror." I will illustrate this with a question: The figure shows a light source A, from an ordinary light bulb, that...
  9. michael879

    Unconsidered source of CP asymmetry?

    I constantly see references to the "strong CP problem" which is basically just the fact that the CP asymmetries in the SM are not large enough to account for the observed CP asymmetry in the universe. What I find odd is that nobody ever mentions the HUGE CP asymmetry caused by our current...
  10. V

    What's the Best Open Source OS for GUI Lovers?

    Any favorites guys? And have you developed any source code personally?
  11. P

    Energy source for hot place on cloudy / rainy days without wind?

    Say you're in a place either 15 degrees north or south of the equator where average temperatures are over 25C (77F), a large majority of days are either cloudy or rainy and there isn't any wind. You need 50Wh a day for your needs and the battery you have happens to have a capacity of 50Wh as...
  12. G

    Electrical Engineering - FET Common Source Configuration with Load

    Homework Statement I'm given this configuration with a AC source at v_{i} with a R_{sig} connect to the source before the capacitor. R_{sig} = 0.6 KΩ R_{G} = 1 MΩ R_{D} = 2.7 KΩ R_{L} = 4.7 KΩ I_{DSS} = 10 mA v_{p} = -6 V Homework Equations The Attempt at a Solution...
  13. E

    Finding The Distance Between An Observer and Light Source

    Homework Statement We are given that a light-bulb radiates 0.1 W from it, and the wavelength of light emitted from it is 530 nm. Seeing as the human eye requires around 6 photons per second for the brain to register a light signal. I am then asked, what is the largest possible distance...
  14. S

    0-1A Bidirectional Current Source

    I'm trying to design a bidirectional current source for the purpose of measuring very small (0.0001 Ohm) resistances. I've come across this circuit: I can see that the transistors are there to 'boost' the current but I don't understand the purpose of the 1K resistors and the capacitor. I...
  15. S

    Finding Vx, Is, and Power in a Dependent Source

    Homework Statement Find Vx, Is and power on the dependent source. The Attempt at a Solution http://s17.postimg.org/3x4hszzkf/002.jpg
  16. Z

    What is meant by the input impedance of a voltage source?

    I am familiar with the concept of the internal resistance of a voltage source, but what is meant by the input impedance?
  17. Jarvis323

    Engineering Solving a simle circuit with a voltage and current source

    Attached is the model. Find Vx and Vy. The Attempt at a Solution The total resistance is 10 ohms, and the circuit elements are all in series. So 2 Amps of current is flowing in the direction of the arrow in the diagram across all elements, Vtotalsrc = (to the voltage from the current...
  18. G

    Sketching the Source Voltage

    Homework Statement Sketch the source voltage from 0 < t < 7T with a source resistance of 0.5*Z_C and a load resistance of 2*Z_C and a signal generator that delivers a 1-V triangular pulse train down a lossless coaxial line. See image attached Homework Equations Equations to find...
  19. K

    Exploring Dark Flow: Evidence of Other Universes?

    Is dark flow evidence of other universes?
  20. P

    AC Voltage Sources Riding A DC Voltage Source

    Hello again, I am having a bit of trouble understanding superimposed voltage. Here is the problem: A sinusoidal AC voltage source is in series with a DC source. Effectively, the two voltages are superimposed. Draw the total voltage across RL. Determine the maximum current through RL and the...
  21. T

    Can Lasers Be Used as a Viable Energy Source Despite Their High Power Output?

    if lasers produce so much power why can't we use it as an energy source
  22. M

    What'd happen if two light source collide w/ each other?

    Imagine this, there are 2 light source (laser perhaps) pointing each other with a distance between them. They have the same frequency, wavelength and amplitude. But, laser 1 start with positive amplitude while the laser 2 start with negative amplitude (start off from negative), what would happen...
  23. E

    Source transformations: confusing problem wording

    Homework Statement A certain practical dc voltage source can provide a current of 10.5 A when it is (momentarily) short- circuited, and can provide of 30 W to a 20 Ω load. Find the open-circuit voltage Homework Equations V=IR The Attempt at a Solution Well I'm pretty sure that...
  24. A

    Pressure as a renewable source of energy

    I am designing a machine to produce electricity , using pressure as a source of energy. So my question is simple, is there any machine or device that are used to produce electricity from pressure?
  25. J

    Source of Dirac Field: Classical & Quantum Explanation

    Classically as well as quantum-mechanically, the source of the Maxwell field is the electron/four-current (Dirac field), so the use of the Green Function propagator for the Maxwell field makes perfect sense: the Maxwell field is inhomogenous in the presence of matter. But what about the source...
  26. fluidistic

    Open source program Sunsetter (chess related) doesn't compile

    Hi guys, I'm trying to compile an open source program (chess and chess variant engine) under linux but for some reason it doesn't work. I know almost nothing regarding programming so I don't know how to fix the problem. In a chess server I asked some programmers if they knew how to fix the...
  27. S

    Source terms in Maxwell's Equations and retarded positions

    Hi All, Thanks again to all the great mentors and contributors to this forum. I wanted to ask a question about the Gauss's law/Ampere's law equations in Maxwell's Equations: \nabla \bullet \textbf{E} = \frac{\rho}{\epsilon_0} \\ \\ \nabla \times \textbf{B} = \mu \left( \textbf{J} + \epsilon...
  28. N

    FET common source analysis with source resistor

    Hi everyone, I have attached an image of fet amplifier in common source configuration. I want to have the ac analysis of this circuit. I am able to figure out the input impedance and the voltage gain. But I can't formulate for output impedance. According to me, while calculating output...
  29. B

    Doppler Effect: Speed Relative to Ground, Source, or Listener?

    hi i just want to ask about the formula of Doppler Effect . The speeds of the listener VL and the source Vs are relative to the ground, source, or listener ?
  30. G

    What is the relationship between intensity and amplitude in a wave source?

    This is something I don't relly get. I keep reading that the intensity of a wave is proportional to the square of its amplitude. So let's suppose we have a random wave source, with amplitude A0. If we replace that source with five identical copies of it, their collective amplitude is 5A, yes...
  31. B

    Source of the first Photon in the LASER

    what is the source of the first photon in the laser ? i understand there is a burst of light or electricity that excites up the medium , but what is the source of the first photon ? is it the light source or is it one atom of the medium itself releasing photon as it gets de-excited * if...
  32. G

    Mcnp error the new source has overrun the old source

    mcnp error "the new source has overrun the old source" I am a beginner with MCNP. This error really confused me. Who knows what this error means? Thank you.
  33. A

    3d heat equation with constant point source

    Hi all, I'd like to solve the following problem in 3 dimensions: \partial_t u(r,t) = D\Delta u(r,t) u(r,0) = 0 u(0,t) = C_o In words, I am looking at a point 'source' that is turned on at t=0 and held at constant temperature. The ultimate goal is to then convolve this solution with...
  34. ShayanJ

    Positive source for electromagnetic energy

    We know that the conservation of electromagnetic energy is expressed via the continuity equation below: \large{\frac{\partial u}{\partial t}}+\vec{\nabla}\cdot\vec{S}=-\vec{J}\cdot\vec{E} with u=\frac{1}{2}(\vec{E}\cdot\vec{D}+\vec{B}\cdot\vec{H}) and \vec{S}=\vec{E}\times\vec{H} . It...
  35. F

    Equation to find relative sound intensity with angle from source

    What is the equation to find relative sound intensity from a source when given the angle?
  36. T

    What Direction is Light Observed From a Moving Source.

    An object is an isotropic light emitting source and the object moves very near the speed of light c. I am an observer on a planet without an atmosphere and I see the path of the object as a line that is perpendicular to the normal from the planet's surface where I am standing. Now take a line...
  37. A

    Electromagnet heat source and efficiency

    So.. I'm a biomedical engineer, and a new technology that is arising is being able to control magnets that "swim" around the body using electromagnets oriented around the outside of the patients body. It has been said that electromagnets can't be used on the inside of the patient because they...
  38. Z

    What are the accepted theories for the source of gravity?

    I have very little knowledge of physics so the simpler you can keep your replies the better for me. Newton put forth a gravity theory that essentially said that there is a force that pulls on us to keep people on the Earth and this is gravity. Einstein came along and included in his theory...
  39. M

    Radioactive Source Emitting Only Alpha and Gamma Radiation

    Homework Statement "How could you show that a radioactive source was only emitting alpha and gamma radiation?"The attempt at a solution This really stumped me...obviously they have different penetration distances, and different strengths of ionisation, but I don't know how to show that only...
  40. M

    AC circuit: is the voltage source absorbing or delivering?

    I'm looking at an AC circuit. There is a voltage source, a resistor, an inductor, then another voltage source. One loop. I am supposed to find the power in each element and tell weather it is absorbing or delivering. I think I remember that when a current goes into the negative terminal of a...
  41. D

    Lithium Hydride as energy source for Combustion Engines

    Lithium Hydride contains more hydrogen per unit volume than liquid hydrogen does, so what is stopping us from developing a Lithium Hydride storage solution to supply hydrogen to a vehicle's engine? The reactivity of the substance would throw up some substantial challenges, but compared to...
  42. R

    Making a quater wave connection and 2 GHz source

    Apologies for what may be a basic question, I am unfamiliar with RF systems but much more familiar with optics. I need to connect some standard coax to some microcoax; they do not have exactly matching impedances so there are reflections. It seems to me I should be able to make an...
  43. mishima

    Good text or online source on Radiometry?

    I'm looking for a good text or online source that can take me through radiometry at an undergraduate level. I'm interested in drill type problems that can help me sort out the different quantities intensity, irradiance, exitance, radiance and their spectral counterparts. Also, solid angle vs...
  44. H

    Audio Source Moving @ Supersonic Speed

    Let's say I have an indestructible speaker and I launch it out of a cannon at Mach 1.5 while it's playing music. (To make things simple, it also has an iPod and battery attached to it.) If the speaker passes a stationary observer, will they hear each cycle of the sound wave from the speaker in...
  45. M

    Is Cs-137 Effective for Calibrating Vintage Geiger Counters?

    So I have a bit of a story here. First of all, I work in my university's radiation safety department, where, among other things, I calibrate Geiger Counters. I also passed Modern Physics (Physics III), so I got some education on radioactive decay. I have an old Counter from 1962, a...
  46. R

    Engineering Circuit Theory Question (KCL/KVL/Dependent Source)

    Homework Statement Here's the problem: Find the equivalent conductance Geq and then the equivalent resistance Req "seen" by the current source Is in the circuit in terms of the literals R1, R2, and gm. Figure: Homework Equations Ohm's Law: V = IR KVL: V1 + V2 + ... Vn = 0...
  47. O

    Calculate the power consumed by dependent source

    Homework Statement calculate the power consumed by dependent source Homework EquationsThe Attempt at a Solution The 10A source does not build a supermesh. Loop 3: (i3-i2).(1/10)=0 => i3=i2 Loop 2 : i2=10(A) i3=10(A) vx.(10)=10=> vx=1(V) (node voltage) also for loop 2 ...
  48. S

    Photon flux from a light source

    Homework Statement What is the photon flux (photons/ m2 s) at a distance of 1 km from a light source emitting 50W of radiation in the visible domain, with wavelength 6000 Angstroms. Homework Equations The Attempt at a Solution Energy of one photon = hc/λ = 3.32 x 10-19J. So, number...
  49. J

    Does a capacitor delay the voltage from a voltage source in a circuit?

    If we have a circuit (see attached) will our voltage source's supplied voltage be delayed by the capacitor in anyway? (as the voltage across a capacitor lags the current through a capacitor by 90 degrees) then, as the resistor,voltage source, and capacitor are all in parallel does this cause the...
  50. B

    Finding voltage across current source

    Homework Statement Homework Equations The Attempt at a Solution
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