Electronics > Beginners
Started a MOOC, is trig and calc really necessary a beginner DC circuits class?
dmills:
--- Quote from: westfw on April 11, 2019, 10:17:37 pm ---"sin(60*pi*t)" is home AC, more or less,"
--- End quote ---
Only if your domestic power is 30Hz!
Regards, Dan.
rstofer:
--- Quote from: westfw on April 11, 2019, 10:17:37 pm ---And realizing that requires knowing some trig AND some calc.
ie, they're "easy trick questions", but only if you know the tricks."sin(60*pi*t)" is home AC, more or less, so perhaps the questions are relevant outside of "signal processing."
--- End quote ---
I actually went to https://www.symbolab.com and stuffed in '7*cos(60 * pi * 4)'. The '4' because the problem specifies t=4. It came back 7. The first part really is 'plug and crunch'.
The second part does take a smattering of calculus. When you try to take the derivative of 7 * cos(240 * pi) to get di/dt, Symbolab gives 0 because 7 * cos(240 * pi) is a constant (because t was a constant = 4) and the derivative of a constant is 0. Or you could do it with slope...
Yes, I actually used Symbolab to get the answers. Yes, it takes a wee bit of trig and calculus. I'm not sure why the problems show up in a DC Circuit Analysis course but I don't see how you could spend an entire semester with batteries and resistors.
The thing is, I don't need to be some kind of wizard to work these problems. There are tools in the realm that make it easy. You do have to a) know about the tools and b) know which question to ask and how.
Note that when plotting this 7*cos(60*pi*x) function with Desmos, the X-axis probably wants to just go from -1 to, say, 3 and then click 'Degrees'. The 60 * pi is ok but it fills the screen with ink unless the scale is expanded. Use the wrench in the upper right corner and set the x-axis as described. https://www.desmos.com/
These are the tools that got my grandson through Calc I and Calc II. I don't know what he is using for Calc III but they will be using MATLAB for Differential Equations in the Fall. I would have loved to have had a tool like that when I took the subject.
Khan Academy is a great help with all kinds of math. They even have a dedicated EE track. This site is just great!
Now, if you want to learn math and you don't mind spending a bit of money for 'tuition', CalcWorkshop.com is excellent! You can learn at your own pace, of course, but the curriculum is expansive. I have had a subscription (for my grandson) for a couple of years and will maintain it as long as necessary. It's cheap in the bigger scheme of things!
https://calcworkshop.com/courses/
It may, or may not, be necessary to start with Algebra but I guarantee that it is PreCalc that sinks students who attempt Calc I without doing it first. Here is where you'll learn trig and all the other tools it takes to succeed in Calculus and beyond.
None of us learned this stuff without a lot of sweat and tears. It takes time, a lot of time!
Ronan:
Thanks rstofer!
I think people got the wrong impression about me and math. I enjoy math, I made it through calc & trig before; I just don't like taking quizzes that involve it when there was zero mention of it in the course material, exercises and videos. I just like to be prepared when I get in the trenches and the course did not give me a heads up. I just have an issue with the pedagogy of a school that has both gaps in the tutorials and doesn't inform the student of what they need to be prepared for, along with quizzing on elements not covered in class; it feels a bit like a bushwacking.
I'll look over everything you said and see if I can figure out how the trig works with respect to electronics. I understand SOH CAH TOA, but with respect to a triangle. I'd have to review some more in applying it to electronics. It might help me to just go ahead and take a full blown trig class so I can nail the fundamentals and start the MIT online series with a solid understanding; and your links will definitely help out. So thank you.
westfw:
--- Quote ---I don't need to be some kind of wizard to work these problems.
--- End quote ---
That's a lot easier to say if you've had trig and calculus, and have merely forgotten the details.
If you're still at the "why isn't di/dt just i/t" stage, it all looks like witchcraft.
Heh. A former coworker of mine is doing ... something, and will make facebook posts like:
--- Quote ---Fun fact of the morning: If a is a unit in a commutative ring then a divides everything in the ring.
(Note that R is a ring rather than a rng!)
--- End quote ---
Yeah. Right... Sorry; they didn't do a lot of theoretical math in the EE curriculum. But I have few doubts that I feel about the same reading that, as our OP does with the unexpected trig and calc in their homework...
westfw:
--- Quote ---figure out how the trig works with respect to electronics.
--- End quote ---
It has more to do with circles than triangles. Polar coordinates and such.
I don't actually recall exactly when that comes up in math classes; I seem to recall that most beginning trig classes mostly do the triangles...
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