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WolframAlpha guide on electrical engineering

  1. May 21, 2009 #1
    Introduction:

    WolframAlpha is a freely available computational engine that can supplement already existing software such as mathematica, maple, mathlab, or excel. The purpose of this mini-guide is to go over some of its functionality with emphasis on electrical engineering.

    www.wolframalpha.com


    Dimensional analysis:


    WolframAlpha recognizes many common units. It will simplify dimensions and scale units. For example,

    Code (Text):
    farad * henry
    will generate [time]^2

    Code (Text):
    0.01 uF to pF
    will generate 10,000 pF or 10 nF


    WolframAlpha also can tap its database to pull up a conversion formula from the context

    Code (Text):
    convert 25 MHz to meters
    will convert the frequency to wavelength 12 meters

    Code (Text):
    find energy in 100 uF at 10 KV
    will give energy in a capacitor,

    or to find inductance to resonate with 10 nF capacitor at 100 Khz; just say that

    Code (Text):
    find inductance for 10 nF at 100 KHz
    output 253 nH

    Also if you haven't memorized resistor color bands already, you can still look them up

    Code (Text):
    resistor yellow purple red
    output: 4.7K


    Complex numbers and phasors:

    Working in polar form is supported in W|A. By typing an impedance in rectangular form

    Code (Text):
    30 + 45i
    we are quickly given its magnitude and phase of 54, and 56 degrees

    and likewise, we can indicate a phasor in polar form with an exponential e

    Code (Text):
    e^(i pi)
    generates -1

    we can also manipulate phasors algebraically

    Code (Text):
    100 e^(i 45 deg) + 25 e^(i 30 deg)
    output: magnitude = 124, phase = 42 deg

    indicate degrees with “deg” otherwise W|A will interpret it in radians.


    Solving equations:

    To solve [itex] x^2 - 2x + 1= 0[/itex], enter the equation as it is


    Code (Text):
    x^2 - 2x + 1 = 0
    output x = 1

    and W|A solves it. Don't even have to specify the variable to be solved.

    Solving systems of equations is just as easy,

    [tex] v_1 + v_2 + v_3 = 4 [/tex]

    [tex] v_1 - v_2 = 10 [/tex]

    [tex] v_1 - 3v_2 + 5v_3 = 8 [/tex]

    simply type

    Code (Text):
    v1 + v2 + v3 = 4, v1-v2 = 10, v1 - 3v2 + 5v3 = 8
    output v1 = 23/3, v2 = -7/3, v3 = -4/3

    just make sure that the equations are separated by a comma.

    Differential equations are supported as well. An nth number of apostrophes indicates an nth derivative, and proceed as before. For example to solve

    [tex] \frac{d^2y}{dx^2} - \frac{dy}{dx} - 2y = 0 \indent y(0) = 1, y'(0) = 2 [/tex]

    enter the code as follows,

    Code (Text):
    y'' – y' - 2 y = 0, y(0) = 1, y'(0) = 2
    and we get a solution y = e^2x as well as a plot that can be saved in pdf format, and printed out.


    We can also maximize and minimize

    Code (Text):
    max 1 - x^2
    finds maximum of 1


    Logic gates and boolean algebra:

    Converts number bases,

    Code (Text):
    binary 1111101 to hex
    = 7d


    We can also work with boolean expression in WolramAlpha, for example

    Code (Text):
    (x or y) and (x or !y)
    generates a truth table:


    http://img200.imageshack.us/img200/9384/truthtable.gif [Broken]

    a schematic with logic gates, and even simplifies the expression to a minimal form

    http://img268.imageshack.us/img268/3233/scehmatic.gif [Broken]

    Here is the supported syntax:
    Code (Text):

    NOT = !
    OR = ||
    AND = &&

    NAND
    NOR
    XOR

    More on calculus:

    W|A can perform basic calculus

    take derivatives:

    [tex] \frac{d}{dt} cos(t) [/tex]


    Code (Text):
    derivative cos(t)
    do integration:


    [tex] \int \frac{1}{x+1} dx [/tex]


    Code (Text):
    integrate 1/(x+1) dx
    and take Laplace and Fourier transforms:

    [tex] \mathcal{L}(x^2), \mathcal{F}(e^x) [/tex]



    Code (Text):
    laplace x^2
    Code (Text):
    fourier  e^x

    Plotting:

    If you want to graph a transfer function for instance,

    [tex] H(s) = \frac{s+10}{s^2 + 4s + 8} [/tex]

    enter:

    Code (Text):
     graph (s + 10)/(s^2 + 4s + 8)
    and here we have

    http://img32.imageshack.us/img32/9715/graph.gif [Broken]


    Conclusion:

    WolframAlpha uniquely combines different tools into a one freely available package and that expands our tool box. This mini-guide doesn't cover all of W|A, it merely touches upon features that can be used in electrical engineering, for more information visit their examples page

    http://www28.wolframalpha.com/examples/

    also, W|A is said to expand in the future, enabling more functionality, and tools.
     
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. May 21, 2009 #2

    berkeman

    User Avatar

    Staff: Mentor

    Thanks for putting that together, waht. I've stickied this thread to help us learn how to utilize W|A.

    Any further posts in this thread should be about tips on how to use W|A and its features. Discussions about W|A and its implications for eductaion, etc., belong in a different thread, like this one: https://www.physicsforums.com/showthread.php?t=307686

    .
     
    Last edited: May 22, 2009
  4. May 21, 2009 #3

    Redbelly98

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    Resistor color codes


    The inverse operation works also. Type this for input:
    Code (Text):
    resistor color 4.7k ohms
    ... and the output is an image of the resistor with the correct color bands:
    attachment.php?attachmentid=19037&d=1242997211.gif


    View the full W|A output here:
    http://www5f.wolframalpha.com/input/?i=resistor+color+4.7k+ohms&asynchronous=false&equal=Submit [Broken]
    .
    .
     

    Attached Files:

    Last edited by a moderator: May 4, 2017
  5. Oct 14, 2009 #4

    Redbelly98

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

  6. Apr 4, 2010 #5
  7. Apr 10, 2010 #6

    ranger

    User Avatar
    Gold Member

    Check out the WolframAlpha app for the iPhone and iPod Touch. Its pretty awesome!
     
  8. Jul 13, 2010 #7
    Remember when the WA app cost $50? They thought because it's better than any scientific calculator could be, they could charge that much, but you know, no one would pay that much so they made it $2.
     
  9. Dec 20, 2010 #8
    is there any advantage over the ipod app vs the standard web version?
     
  10. Jun 17, 2011 #9
    Would you guys recommend wolfram alpha to a student who is interested in learning more about physics and modeling physics within computing systems? I have a small bit of experience with mathlab, and am hoping to be on the go as I do this (iPad, Android, etc.)
     
  11. Sep 14, 2011 #10
    I have "Algeo.apk" in my galaxy tab, it is a wonderful application in small scale.
     
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