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. E

    Is transformer always 'source' to which current returns?

    I am not sure if I should use the word 'current' or 'charge' but my question is whether, in a typical U.S. residential 120/240 split phase system, is the local transformer always the source to which current (charge?) must return? Or can it bypass and go direct to other PoCo elements/generators...
  2. Astronuc

    I Ultraluminous X-ray source in the galaxy NGC 55

    https://phys.org/news/2021-11-ultraluminous-x-ray-source-galaxy-ngc.html Spectral and Temporal Properties of Ultra-luminous X-ray Source NGC 55 ULX1 https://arxiv.org/abs/2111.06637 Same paper - https://academic.oup.com/mnras/advance-article-abstract/doi/10.1093/mnras/stab3307/6428406 From...
  3. PhysicsTest

    Voltage source and current source

    As per ohms law the current is generated based on voltage and resistance V=IR. So if 5v and 1k resistor the current 5mA flows in resistor. But if I take a current source, can I pump any amount of current to resistor? So, current drawn is not characteristic of resistor?
  4. S

    Engineering Using Kirchhoff's Laws to Solve a Circuit with Two Batteries

    Okay so This is what I've tried; a) A formula I've found in the lecture notes; $$ U_a = U_q - R_i*I $$ To get I used the ## I = \frac{P}{U} ## formula I get I to be 0,46 A.Now put back in formula for and rearange to get Ri should be $$ \frac{Ua-Uq}{I} = Ri $$ and the solution should be 0,43...
  5. A

    How to create a conical source (mamography) in Vgate

    I am new in Vgate software. I've tried a lot of things, but nothing works. I need to create a conical source that is 4 cm in radius and 16 cm in length. Example in photo attached
  6. A

    B Source radioactivity estimate from a radiation detector

    If I have a source of radioactivity that is concentrated instead of evenly spread out, like a "tablet" source instead of a evenly distributed aerosol/dust on ground for example then is it possible to even estimate the total number of disintegrations (Becquerels per second) by measuring the...
  7. fluidistic

    Steady state heat equation in a rectangle with a punkt heat source

    I have checked several textbooks about the heat equation in a rectangle and I have found none that deals with my exact problem. I have though to use separation of variables first (to no avail), then Green's function (to no avail), then simplifying the problem for example by defining a new...
  8. R

    B Free fall floating in a closed spaceship near a gravity source

    Floating inside a closed spaceship, no windows, not knowing if I'm free falling near a gravity source or far away from any gravity source, are there any experiments that can be made, to determine if there is a gravity source near and if there is such an experiment, to determine the gravity...
  9. Christoffer B

    I Channel electron multiplier as an electron source

    Hi! I'm playing around with a type of electron (and by electron/molecule interactions: ion) source that was briefly touched upon in the 1960's. The basic idea is to use a channel electron multiplier "channeltron" with the anode removed; similar to a single MCP channel. The burst of electrons...
  10. mesa

    Looking for a good source to find FPGA developers for ADC PCB spinouts

    Summary:: I am trying to find some good folks with knowledge in FOGA coding for some ADC boards our EEs are spinning out, but am having terrible luck so far... I am trying to find some good folks with knowledge in FPGA coding for some ADC boards our EEs are spinning out for pulse heigh...
  11. K

    What's the source of increase in rotational energy of carousel?

    A carousel has the shape of a circular disc with radius 1.80 m and a mass of 300 kg. There are two people with masses of 30 and 45 kg out on the edge while carousel rotates with the angular speed 0.6 rad / s. The people move towards the center of the carousel Calculations show that the...
  12. N

    B Confused About the Source of CMB Photons: Two Possibilities

    I am still so totally confused about the ultimate source of the photons of the CMB. I am getting really confused by online sources, who are either not very clear, or seem to contradict each other. I feel like I have narrowed it down to two sources; 1. The early universe was full of high...
  13. M

    Treatment of source term on the boundary: FEA and Comsol

    I would like to solve a coupled system of two PDEs using Comsol for the following geometry: Equation 1 (valid for 0⩽Z⩽bm): The initial and boundary conditions are: Tm(r,t→0)=20 Tm(r→rw,t)=70 Tm(r→∞,t)=20 However, for bm⩽Z⩽bm+b2, the equation to solve is: With the following initial and...
  14. R

    B Can EM Radiations Exist without a Source?

    Can electromagnetic radiations exist on their own without any source (i.e light existing on its own without flashlight). If light can't exist on its own so sources are necessary for light or any EM radiations in order to exist, how about the EM fields?
  15. fsonnichsen

    Seek Open Source Web Design Software for Serial Controlled Systems

    I am hoping this forum may be a good page for this question. Not sure where else to post. I have been asked if I can write a user GUI to control a system that we build--the system is made with the fairly common electronics board designs and PIC MPs and presently is controlled from a...
  16. meher4real

    Finding Color of Two Lights Given Slit Source & Screen Distance

    Given values : - Distance between the slit source and the screen L - d1,d2 The problem is to detemine the color of the two lights
  17. Secre

    Engineering How to deal with dc source on ac circuits?

    We are tasked to solve for the steady state voltage v using superposition theorem. I start with solving with voltage source using mesh analysis and got the current flowing through the 3 ohms resistor and get the first value of the voltage which is 3.2cos(6t+126.87). Now my problem is I am...
  18. A

    I Is mass the source of spacetime?

    Mass curves the spacetime. In electrodynamics, an electron curves an electric field (if there is one) - because it has an electric field of its own. The electron is the source of an electric field(maxwell equations) Is there an analogy to space-time, is mass the source of the space-time field as...
  19. N

    Source Level calculations of an Underwater Cylindrical Acoustic Array

    Hi all I am trying to calculate Source Level 'SL' of a underwater acoustic Cylindrical Array with multiple Transducers. The array has 03 Rings with 32 transducers in each Ring. The spacing between each ring is around 0.18m whereas Dia of each Ring is about 1m. Each transducer is being driven...
  20. S

    Calculating distance between lux meter and light source

    I am currently performing some experiments to calculate the distance between a light source and a lux meter where the light source points directly towards the lux meter. Is it possible to calculate the exact distance between the light source and the lux meter given that we have a lux value...
  21. hquang001

    Resistor is connected parallel to Voltage Source

    .
  22. G

    Mirror box with 1 candela of luminous intensity light source

    considering that a simple mirror may reflect 99.9% of the visible light
  23. Xiao Xiao

    Engineering Help in Electric Circuit Analysis -- One current source and a resistor network

    o9
  24. Mayan Fung

    Electric field acting on the source charge

    I am reading Griffith's textbook on EM. There is a problem asking to find the force acting on the northern hemisphere by the southern hemisphere of a uniformly charged sphere. The solution idea is to find the expression of the E field by Gauss's law and integrate the force over the northern...
  25. user366312

    Python Kindly explain this source code for me

    Check this link: How to override the copy/deep-copy operations for a Python object? Can anyone explain, in layman's terms, what is going on in this source code? from copy import copy, deepcopy class MyClass(object): def __init__(self): print('init') self.v = 10...
  26. F

    How to Judge the Linearity of a Dependent Current/Voltage Source

    How can we evaluate the linearity of a dependent voltage/current source? Components like resistors are easy to deal with because they always obey a linear equation. Dependent sources are more complicated because their voltage/current relationships depends on other parameters within the circuit.
  27. LCSphysicist

    Derive the Maxwell "with source" equation

    We need to derive the Maxwell "with source" equation, of course, using the tensor equation $$\partial F^{\mu v}/ \partial x^{v} = j^{\mu}/c$$ D is the spacetime dimension To do this, it was said to us vary the action wrt the ##A^{\mu}## The first term just vanish, and I want to evaluate the...
  28. wcjy

    Source free RLC series circuit

    Hello, this is my working. My professor did not give any answer key, and thus can I check if I approach the question correctly, and also check if my answer is correct at the same time. for t < 0, V(0-) = V(0+) = 60V I(0) = 60 / 50 = 1.2A When t > 0, $$α = \frac{R}{2L}$$ $$α =...
  29. F

    What is the source of inertia?

    Is there a specific particle or force that gives an object inertia? Going back to the 1940's science fiction ideas of "inertialessness", is there a way to nullify or remove an objects inertia? And if so, could an inertialess object go faster than light?
  30. X

    Engineering Find di/dt and dr/dt for a DC circuit with indepedent current source

    Dear PF, I am trying to solve practice problem 8.2. I am stuggling with part B of the question which asks us to find diL(0+)/dt, dvC(0+)/dt and dvR(0+)/dt. My attempt can be seen below. Before t=0 the 4A current source is not present and thus it is an open circuit. A capacitor acts as an open...
  31. E

    I Source of Gravity of heavy mass as per GTR

    Regarding the equivalence principle of GTR, inertial mass and heavy mass are comparable, and are causing identically effects on mass objects. The pseudo force of inertial mass could be experienced in an accelerated frame of reference. In that point the "Force" appers, while energy is...
  32. The Bill

    Geometry General Ellipsoid Area Formula: Detailed Explanation

    I'm looking for a source that fully derives the complete formula for the surface area of a general (triaxial) ellipsoid. I'd prefer a source that has more than just a full derivation, but also has a fair amount of prose discussion on this topic. Some historical context would be nice, as well...
  33. R

    I LRC Series Circuit with an AC Source

    Attached is the section from the book. I am doing section 31.3 We know that an AC source gives a sinusoidal varying current, and as far as I know its always given by ##i(t) = Icos(wt)##. Its like we take the current to be the base of all other quantities, so we use it to derive everything else...
  34. WhiteWolf98

    Calculating Discharge Rate of Fluid in Circular Area

    This is actually right at the start of another derivation, but I can't understand how the author gets the formula for ##q##. So the discharge per unit thickness is the circumference of the circle, multiplied by the velocity at that point (at ##r##)? I thought the formula for flow rate was...
  35. B

    Looking for a source of the material properties of various alloys

    I'm looking for a book series tabulating various mechanical and material properties for metals and alloys. There is a book series called "Thermophysical Properties of Matter" and it details the thermophysical properties of hundreds of elements and compounds (even including some obscure uranium...
  36. C

    I Material source of the quasar redshift

    When I see discussions about quasar redshift, exactly what are they talking about? I assume a quasar is similar to a black hole, so emits little radiation from the main mass. The light from a quasar comes principally from its jets of accelerated material, no? Which means the jet pointed...
  37. Buzz Bloom

    I The source of the dust in Martian dust storms

    The article I first read which discusses this topic is: "IDing Mars' Dust" by Dale Keiger Johns Hopkins Magazine Volume 70, Number 4, Winter 2018 Page 20 The principle researchers are Assistant Professor Kevin Lewis of Earth and planetary sciences in the Krieger School, and postdoctoral fellow...
  38. S

    Code / Software for Dynamic Balancing (Free / Open Source)

    I am thinking of doing a DIY project in which one sub-task would be to dynamically balance a small assembly that will be spun up by, for example, a small motor taken from a DVD drive. As a test case, here is a setup where we would like to adjust screws S1 to S6 such that the cylinder is...
  39. M

    Gravitational wave source triangulation

    In my new novel, Handwavium, renowned genius physics Professor Samuel Clements Silver has created a prototype gravitational wave radio. For plot purposes, the protagonist needs to use the signal to triangulate his location. I know LIGO has three detectors and have seen reports of sources like...
  40. A

    How far from the mirror should the light source be positioned?

    C= mirror center O = vertex I don't know if the design is right, if someone can show me the correct one. I also don't know how to proceed in geometry Solution: Lf / ( L - f( 1 + d/D))
  41. dRic2

    How to measure the activity of a radioactive source

    Hi, I've been reading about radiation detectors (manly form Knoll's book), but there is something I don't understand. Radiation detectors are of very different nature, but they all share a common process to detect a type of radiation: - I have a control volume - The incoming radiation interacts...
  42. G

    Method of characteristics: Discontinuous source

    Hello all, this question really has me and some friends stomped so advice would be appreciated. Ok so, the relevant (dimensionless) continuity equation I have found to be $$\frac{\partial\rho}{\partial t} + (1-2\rho)\frac{\partial \rho}{\partial x} = \begin{cases} \beta, \hspace{3mm} x < 0 \\...
  43. jasmin_89

    Calculating Minimum Power for Perception of Radiation from a Point Source

    Hallo, can anybody help me and check if i have the right result: What is the minimum power P that a point source of radiation (I=8*10^(-7) W/m^2) at a distance of l=10 m from the listener must have in order to still be perceived? (Note: The emitted energy per area can be related to a spherical...
  44. PeterDonis

    Insights Is Pressure A Source Of Gravity?

    Continue reading...
  45. F

    Image charge of source charge in spherical cavity

    All are used to finding the image charge induced by a source charge outside a conducting sphere. The solution is supposed to also work for the case where the source charge is inside the conducting sphere, in which case the sphere is now a conducting cavity. But the solution suggests the image...
  46. nineteen

    What is the standard definition for what an "electric source" is?

    The syllabus states : "Explain that the potential difference which is needed to apply across any electric circuit to flow current is supplied by an electric source". To explain this and make notes, I want to first understand what an electric source particularly is. And how all those electric...
  47. jisbon

    Circuit Analysis - Source Transformation

    My work seems to be wrong somehow since my answer is wrong, and I need your help to find out which part is going wrong for me :/ My work: 1. 2. 3. 4. 5. 6. (10/7)/(10/7+7) = 0.7627A, which is not the answer. May I consult where is the problem in solution? THanks
  48. F

    How to operate a Variable DC source

    Hello, I am experimenting with DC variable power supply and want to make sure I am using it correctly. My understanding is that it can output a variable DC voltage by turning the voltage know CW. The current-limit knob, as far as I know, is only there to set the maximum current that we would...
  49. R

    Source for Reviews/New Listings for STEM Titles

    The WSJ and the NY Times, among other media sources, have their best sellers/new titles lists of published books. I seek the same but for STEM titles. (STEM is the acronym for Science, Technology, Engineering and Mathematics.) I can find such lists recommending history or biography or other...
  50. E

    Putting internal resistance in series with a voltage source

    Suppose I have a galvanic cell, where I've arbitrarily set the (-) anode to have a potential of zero volts and the (+) cathode to ##\epsilon## V. The electrodes are connected via the load, but also via the solutions and salt bridge in the centre. Edit: The two trailing wires are connected to a...
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