Should I stick it out in EE with weak-ish math?

[BuddhaBelly34]

Basically I am worried that my inaccuracies in math will doom me in an EE career. I get the concepts with a 90-100% understanding, but it never ceases to fail that I make B's on my tests (since trigonometry). I usually make C's if I have done 0 studying for the test and never make failing grades regardless of time spent studying. I make better grades than most in my class, community college ftw, but I want some advice from those who are Seniors in the major or who have been in the field for some time.

Should I stick with it? Or will dumb errors like forgetting a negative sign in my calculations end up ruining my career as an EE? Are these grades even ancillary to being successful in the field?

I'm a second semester freshman for what it's worth, in calculus 2 of a 3 semester sequence (still single variable).

Thanks in advance!

PS, Be brutally honest because this is the difference between wasting 3 years or just moving on and accepting that I need to do something else. No feelings will be hurt.

 

[skeptic2]

The deciding factor is whether you like EE or not. I made dumb errors in school too but a few years out of school I found myself the only EE in an engineering dept. so there was no one to catch any errors I made. Very quickly I learned to check and double check my work.

 

[DragonPetter]

There's no reason to let this hold you back.

Accurate answers and solid mathematical analysis are the backbone of most EE fields, but few people actually think about this in their designs and day to day work. Usually something is working off of one or a few mathematical/physics principles and you go from there.

If you design something and forget to put a - sign in one of your calculations, you're either going to see something wrong in the simulation, prototype, or other calculations.

There's lots of common sense methods people use to catch their mistakes in engineering work, and unlike a calculus exam, you can go back and change your answer when you find out its wrong. As long as you are competent in doing the math and understanding it, you should be fine.

 

[BuddhaBelly34]

@skeptic2 -
I am getting better about checking my work. I've increased my grades from low B's to high B's because of it.

I enjoy EE, at least what little bit I have experienced, but it's hard to say for certain when you don't get to experience a lot of it during your first two years in.

I'm highly interested in power systems engineering but, unfortunately, the only EE I've experienced in school is electronics. Don't get me wrong I like it, but I don't see myself making a career out of that sub-field.
Is it common in engineering for that to happen? People bail after a few years in the field?@DragonPetter -
Thanks for the reply. I always get into it with professors about this, "unlike a calculus exam, you can go back and change your answer when you find out its wrong.". I understand that they need to test our understanding of a concept without a book, but it seems ridiculous to simulate an environment that isn't remotely applicable to working for a company (ie, in a room with no materials trying to solve a problem).

 

[DragonPetter]

I am getting better about checking my work. I've increased my grades from low B's to high B's because of it.

I enjoy EE, at least what little bit I have experienced, but it's hard to say for certain when you don't get to experience a lot of it during your first two years in.

I'm highly interested in power systems engineering but, unfortunately, the only EE I've experienced in school is electronics. Don't get me wrong I like it, but I don't see myself making a career out of that sub-field.



Is it common in engineering for that to happen? People bail after a few years in the field?

My advice is do what you've done; focus on improving your grades. The better you do in these core courses like calculus and differential equations, the more you will be grateful at the end. It is very worth it.

And, this also covers you if you decide to switch majors. You will still have all the math required to go into pretty much any other undergrad level major.

Electronics is important, even in power engineering. Just learn as much as you can, and if power engineering is your interest, it will come easy to you when you get the chance to study it.

I think the most common EE drop out is while still in school, usually at the sophomore/junior year, a large chunk of the class drops out.

I know that many EEs go into non EE jobs though. If you don't like EE, you're better off switching as soon as possible, but if you can make it through EE you will be glad you did, even if you end up baking cupcakes for your local citizens with a self owned business.

 

[DragonPetter]

@skeptic2 -
@DragonPetter -
Thanks for the reply. I always get into it with professors about this, "unlike a calculus exam, you can go back and change your answer when you find out its wrong.". I understand that they need to test our understanding of a concept without a book, but it seems ridiculous to simulate an environment that isn't remotely applicable to working for a company (ie, in a room with no materials trying to solve a problem).

Well, I think exams are a good exercise and important. You don't need to be perfect to be successful, but your level of understanding shows quite well with how you perform on an exam. It also tests your problem solving abilities.

I can read through a hundred examples of how to do problems, and I'll get the right answer every time. But when a fresh one is put before my eyes without example help, I am finding out if I really know how to do it myself.

Having this power at your brain's "fingertips" leads to synthesis of a lot of ideas and original thinking and makes you a sharp engineer who can dive into colleagues work and research. Exams measure how well you understand something, even if its under stressful circumstances. My EE professors put it in a bit of a condescending way, but they would say problem solving is for engineers, and cookbook (looking in your book for how to do a problem) is for technicians who work for engineers. I don't entirely agree with it, but that mentality of focusing on problem solving and concepts rather than formulas will make you a much better engineer.

 

[skeptic2]

I enjoy EE, at least what little bit I have experienced, but it's hard to say for certain when you don't get to experience a lot of it during your first two years in.

I'm highly interested in power systems engineering but, unfortunately, the only EE I've experienced in school is electronics. Don't get me wrong I like it, but I don't see myself making a career out of that sub-field.

Is it common in engineering for that to happen? People bail after a few years in the field?

Here I have to agree with DragonPetter. Most of the bailing is done while still in school. Once you've gotten an engineering degree, you'll have what it takes to become an engineer. After graduating, each one finds his own niche. Of the two engineers in my class that I've kept track of, one became a sales engineer and the other a computer systems analyst. There are a lot of different directions you can go in with an EE degree.

The interest in electrical engineering seems to have declined substantially since I was in school but I doubt if the demand has. In many industries there is a high percentage of engineers nearing retirement with not nearly enough graduates to replace them. Go with whatever interests you the most.

 

[yungman]

Basically I am worried that my inaccuracies in math will doom me in an EE career. I get the concepts with a 90-100% understanding, but it never ceases to fail that I make B's on my tests (since trigonometry). I usually make C's if I have done 0 studying for the test and never make failing grades regardless of time spent studying. I make better grades than most in my class, community college ftw, but I want some advice from those who are Seniors in the major or who have been in the field for some time.

Should I stick with it? Or will dumb errors like forgetting a negative sign in my calculations end up ruining my career as an EE? Are these grades even ancillary to being successful in the field?

I'm a second semester freshman for what it's worth, in calculus 2 of a 3 semester sequence (still single variable).

Thanks in advance!

PS, Be brutally honest because this is the difference between wasting 3 years or just moving on and accepting that I need to do something else. No feelings will be hurt.

Let me first make you feel good before the brutal honesty. Math is not the most important thing in the job, but it is very important in school. The important thing is you seems to like this field enough to even come here to seek opinion. It is very important to work in a career that you enjoy. If you enjoy the subject, you can get good at it sooner or later. I was an engineer for close to 30 years, never have a degree in EE and mainly learn from self study. I got C's in Calculus 1 and I studied only part of Calculus 2. I did very well in my career, promote to senior EE and manager for many years. So I did it with lousy math. Now come the brutal part:

When you get to the upper division, it becomes very critical. If you are weak in math, you better button up and work on it. I am not here to make you feel good. There came I point I hit the ceiling because the upper division books are written in math. If you don't believe me, go look at the electromagnetics book, signal processing, RF amplifiers, communication etc. You are not going farther than chapter one before you find yourself drown in math formulas. You don't do good in math, you don't understand it. I can't really understand the upper division books. I am not saying to discourage you. It was getting so apparent to me and I felt bad enough that even after I retired, I determined to overcome this. I actually went back and restudied starting from calculus 1, 2 and 3. I even studied ordinary differential equation and partial differential equation and then study electromagnetics. It is that important.

I can understand about getting a C even though you don't study. That's is exactly what is wrong with the education system in US. Those public school like community colleges concentrate on political correctness rather than to educate. They make it so you have to fail the class to look good. If you get a C in community college or even in a lot of the state U, don't count on you understand the subject. Getting a B just only mean you barely understand the subject. That's the reason why US wasted so much money for public education system and we are close to the bottom of the barrel compare to the rest of the civilized world. I came from Hong Kong in the 70s only finish grade 11. I enroll in USF which is already a private school. I was thinking at the time whether the school was a joke. I never realized that USF is by no means a lousy school until I enrolled in SF city college and later in another community college for a few classes, then I realize USF is not bad in US standard.

You want honesty, you got it! I lived with lousy math and I paid for it. And I felt strongly on what I said above. And that's the main reason I devote time here to try to help students that care enough to ask question, there is hope for them and we should encourage this.

 

[BuddhaBelly34]

Replying from a smart phone so I may miss a bit, but I'm gathering that math may only limit me in the height of my career?

I want to get better at math, but it seems like I don't get past the silly mistakes.

When does the ability to recognize novel problems kick in? I doubt many people possesses this ability at my level (Cal 123) but is there some point at which you have had enough math that you are able to approach a new "problem" without viewing examples?


Sorry if my post seems scatter brained, my phone is fighting me. Haha I can clarify anything later.

Thanks for the replies!

 

[psparky]

I agree with most that is said above...but here is the fact. The zero studying (which I did as well in high school) will cease.

Your math along with all your other subjects will be incredibly difficult in college compared to what you are used to...and even more so since you are not studying now. They REALLY want you to know the material in college...not just the memorizing of patterns and so forth you can do in high school. Now you REALLY have to think. Your current "C" grade will now yield you a 20% on an college exam.

In other words...you will be studying 6 hours a day or more 7 days a week in order to achieve a 3.0 in college. So...this is going to be a shocker considering you've never done anything like this before.

Here's the good news. Buckle down and study in college...and you will be fine. Might want to start practicing NOW!

More good news: Once you apply yourself and start learning...you will actually enjoy the ride!

So to summarize your question...you are not weakish in Math...you are just weakish in studying!

 

[BuddhaBelly34]

I agree with most that is said above...but here is the fact. The zero studying (which I did as well in high school) will cease.

Your math along with all your other subjects will be incredibly difficult in college compared to what you are used to...and even more so since you are not studying now. They REALLY want you to know the material in college...not just the memorizing of patterns and so forth you can do in high school. Now you REALLY have to think. Your current "C" grade will now yield you a 20% on an college exam.

In other words...you will be studying 6 hours a day or more 7 days a week in order to achieve a 3.0 in college. So...this is going to be a shocker considering you've never done anything like this before.

Here's the good news. Buckle down and study in college...and you will be fine. Might want to start practicing NOW!

3.4 currently in college. However I have a huge buffer from needing lower level math credits since I did not take the SATs.

I do every bit of homework I am assigned (multiple times if i did not "get it" the first try) and I do study for comprehensive finals, became its absurd to think I. Could remember 4 months worth of information without a review.

I've just never been taught to study. The secondary education system in the states is so incredibly.laughable that I was able to get through it doing g no homework. Don't get me started on the pathetic state standardized tests. How kids are held back by those is beyond me.

 

[psparky]

3.4 currently in college. However I have a huge buffer from needing lower level math credits since I did not take the SATs.

I do every bit of homework I am assigned (multiple times if i did not "get it" the first try) and I do study for comprehensive finals, became its absurd to think I. Could remember 4 months worth of information without a review.

I've just never been taught to study. The secondary education system in the states is so incredibly.laughable that I was able to get through it doing g no homework. Don't get me started on the pathetic state standardized tests. How kids are held back by those is beyond me.

Oh...you are on the right track. A state college is likely to be a different story.

You're first "F" at a real college should do the trick in teaching you to study! lol...but it's true!

But really...doing your homework backwards and forwards is really all the studying you need for the most part. I almost never read a text in engineering...just sample problem after sample problem...etc...etc...etc...

Here's one more thing...you will never be taught how to study...however...you will teach yourself...or you will fail...muhahahahaha!

You'll be fine...just ramp up accordingly...just like a control system...

 

[real10]

i got 650 in math sat. 680 on the 2c/physics nothing great...but kept working/studying...ended up with 3.55/4.00 (round to 3.6 yeah at Penn State College EE 4 years)
did well math classes undergrad...garbageload of selfstudying via books,internet..to keep up with smarter people around me...ups and downs but people prolly get smarter as time goes on who knows...
So yeah don't lose hope (self study via books and internet)
one of my ee professors remmembered the integral of acrtan out of the blue (inverse of a polynomial)
EE is full of crazy smart people (Prof and students) heads up...

 

[psparky]

Btw...you are supposed to kinda have a weak mind right now. You're a freshman in college. The whole point is to build your mind and turn you into a thinker!

Think about how awesome you are going to be after 20 or 30 years engineering experience. It's good that you are critical...but realistically, you are just learning...it's all good.

 

[psparky]

In my mind...here is what a real school is going to do differently.

Essentially, when they give you an exam...they assume you know all the material taught in class and in the books.

But now...they give you a bunch of questions you are not familiar with...things you've never seen before. In other words...you need to take the assumed learned information...and let's see what you can do with it. So not only do you need to learn really tough material...you now need to twist it and manipulate it in ways you didn't know existed.

You know how students complain..."Oh...we never studied that...or oh...we never saw that before!". If you are at a good school...these are the only problems you are going to see!

 

[BuddhaBelly34]

Good. I hear similar things from my professors, but its hard to see them as objective when (in a round about way) I pay their salary.

Yes, in my intro to engineering course I got to, for once, see the smarter folks in action. Granted there were tons of less math/sci inclined people there too.

I'm stoked for the future. I doubt I will come up with something incredible for the field but it is my life's dream. I want to be Tesla. I've come to terms with the fact that I am not, but I think that says something g about my desires.

Like some already said, I definitely have an interest in all of this, its just sometimes easy to lose sight of that when all you get early on is math/phys and mediocre grades. Its never clear how that transfers over and no professor is able to explain it since they are never EE or any Eng for that matter. The most I get is "you'll use some areas of math and maybe never see some other stuff again."

I've also heard "its important to know the concepts so you understand what the calculator is doing and that will indicate whether or not your answer is accurate." In regards to testing some.numbers in simulation.

 

[BuddhaBelly34]

@spark's last post

Is there a good way to approach this type of testing or is it "do example prob after example prob" until you have a very good understanding of the concept, to the point that I can use it on something more difficult than what was covered in the lecture?

 

[psparky]

Some guys will disagree with me on here...but in my opinion...for 90% of the EE's out there...the biggest calculation you are going to need is going to be solved by using plain old algebra. It's good to know the upper math...but you are almost never going to use it in a real world situation. There are some exceptions...but for most...no.

I didn't use any math my senior year...and very little math other than algebra my junior year. You'll use some basic deravatives and integrals...but that's about it.

However, differential equations is going to challenge you quite a bit...along with the DC transient circuits that go along with it sophomore year.

If you are willing to study...there is nothing you can't learn assuming you are of average or above intelligence.

 

[psparky]

@spark's last post

Is there a good way to approach this type of testing or is it "do example prob after example prob" until you have a very good understanding of the concept, to the point that I can use it on something more difficult than what was covered in the lecture?

It's really just trial and error and developing your mind. It will take time.

I always found that teaching other students the subject mattter was a great way to learn. If you can teach something...you truly know it. Also, with you teaching them...they are constantly going to question what you are saying...which is going to make you think even deeper to answer their question...therefore making you smarter and smarter as you go.

If you don't have a study group...Whever you learn something...picture yourself teaching it to a bunch of people. Can you explain everything about the subject in every way possible? If so...you got it! If not...keep studying.

 

[DragonPetter]

Some guys will disagree with me on here...but in my opinion...for 90% of the EE's out there...the biggest calculation you are going to need is going to be solved by using plain old algebra. It's good to know the upper math...but you are almost never going to use it in a real world situation. There are some exceptions...but for most...no.

I didn't use any math my senior year...and very little math other than algebra my junior year. You'll use some basic deravatives and integrals...but that's about it.

However, differential equations is going to challenge you quite a bit...along with the DC transient circuits that go along with it sophomore year.

If you are willing to study...there is nothing you can't learn assuming you are of average or above intelligence.

I agree, the majority of calculations are just simple algebra, multiplication, divide, and addition.

However, integrals and derivatives are pretty common, even if you aren't explicitly solving them. I think most EEs are in some field that requires calculus in some form or another.

I've used fourier/laplace transforms in a very real and useful application though, and I plan to in future applications as well.

And just because you don't use much calculus and diff eq in a job doesn't mean you shouldn't have learned it to understand how things work anyway.

 

[BuddhaBelly34]

I, in no way, have a problem learning and using the math. I just worry that my mistakes will stop me from staying in the field. Its the human condition to be wrong sometimes but being consistently wrong is what worries me.

If moat of what I encounter ends up being basic integrals and derivatives I'm sure ill be okay, but in terms of higher level stuff that I haven't learned I fear my stupid mistakes now will be exacerbated then.

PS, most useful bunch of people that I have ever encountered on forums. Granted this is the first forum I have joined that relates to a subject that doesn't have trolls lurking in every corner.

 

[yungman]

Don't let me or anything discourage you. Math is an acquired subject, you don't born with it. It is like a new language. In fact, math is the language of science. After you pass the first two years, you'll find everything is explained in math. Many of the theory derived from math equation, not by simple theory like op-amp and simple network theorem. When you get to EM, modulation, communication, signal processing, everything are derived by math, it in not intuitive if you don't understand math.

Good news is you can make it up. I did, I am telling you from my first hand experience from lacking of math to have more than enough math for any undergrad colleges. I spent over two years dropping everything and concentrated on math, studying 6 days a week, 3+ hours a day to make up the math. Yes, I did it after I retired! It is that important.

You don't use much math on the job, but you cannot get pass the third and forth year without it. But then of cause, if you want to get the feel good C's, you can get by! I have to say, after studying back all the math, I sure look at things differently, more insight and feel of the subjects.

If I were you, I'll spend one semester concentrate on re-study the math, particular trigonometry, review basic geometry also. I had to finally stop everything and start over. Now I feel good about what I did, it's all worth while for me.

Electronics is not that hard, it's the math. It is easy for a math major to go into electronics and the more difficult part of electronics are all math. EM is part of the very advanced vector calculus. A lot of the Fourier Transform in modulation and communication is in partial differential equation. Closed loop feedback theory that use Laplace Transform is in ODE and PDE. You get the drift? that you are not going to go far without math. You don't get to vector calculus, ODE and PDE without a good foundation of Cal 1 and 2.

I know I am not helping and that's likely not what you want to hear. But this is my experience and I live it.

Lastly, you ask when can you start to feel good. You keep working on it, again and again. All of a sudden, one day, you just feel it. I studied the subject 3 or 4 times, I could have got A's in the class after the first time, but I don't feel anything, then I use another books and studied over again. All of a sudden, you just feel you get it. It is not how fast you can study it, it is the final result whether you really understand it that counts. I am not slow based on my whole career, I am actually considered pretty fast, took me a long time to get the feel of math and EM. That has nothing to do with getting A's, how many people getting A's really understand the subject? It's two totally different thing. Go for the understanding and feel, take you time, start slow, work hard. When you excel, no body will ask you how long it takes you.

 

[yungman]

Let me put this in a new reply. If you have to slack off in school, slack off in the electronics class instead. If you excel in math, you have the rest of your life to read the books as needed in the future. If you don't do good in math like me before, you'll get stuck trying to read the books on the job. Consider math is the language of the scientific world, it is like English, it is a way of communication.

 

[psparky]

I, in no way, have a problem learning and using the math. I just worry that my mistakes will stop me from staying in the field. Its the human condition to be wrong sometimes but being consistently wrong is what worries me.

If moat of what I encounter ends up being basic integrals and derivatives I'm sure ill be okay, but in terms of higher level stuff that I haven't learned I fear my stupid mistakes now will be exacerbated then.

PS, most useful bunch of people that I have ever encountered on forums. Granted this is the first forum I have joined that relates to a subject that doesn't have trolls lurking in every corner.

Thanks man!

One more thing...everyone makes those silly little mistakes at your level...at any level really. Keep in mind your profs give partial credit.

In my mind...and yours too shortly...math is simple...setting up the problem is the hard part! Really...think about it.

More than 50% of your EE is also going to be V=IR. Getting to the V=IR part may take 6 steps...but sooner or later...yep...V=IR

Be patient and grow...you have no other choice!

 

[BuddhaBelly34]

Thanks man!

One more thing...everyone makes those silly little mistakes at your level...at any level really. Keep in mind your profs give partial credit.

In my mind...and yours too shortly...math is simple...setting up the problem is the hard part! Really...think about it.

More than 50% of your EE is also going to be V=IR. Getting to the V=IR part may take 6 steps...but sooner or later...yep...V=IR

Be patient and grow...you have no other choice!

Yeah partial credit somewhat worries me though. It makes me feel like that 80 something is really a 60 something.

LOL V=IR. I can do that. Getting to that point definitely sounds like the hard part. This is my problem with physic. Never having had to take a written scenario and make my own picture is something that I am not at all used to.

Study study study. I need to do this. I will do this.

yungman - I know I need the math, you're not bumming me out. I just wanted to verify mistakes now holding me back (or not) in the future.

It sounds like it won't be as big of an issue as I make it out in my mind. Which is to say, I make it out to be the Armageddon of my EE career before it has even begun.

 

[psparky]

If you want to get a head start on EE...click on the link I just wrote today.

It's the basics...the foundation of EE. You can get a head start if you like...

www.physicsforums.com/showthread.php?t=588404

 

[BuddhaBelly34]

Ah yeah, much of that I have no idea about. I will definitely read up on it though!

I'm in a lab this semester that uses a lot of this stuff (I assume) but apparently the class (after speaking with the professor) is geared more towards using the equipment and writing the lab reports. The theory comes later he says.

This pains me a lot because I like to understand what I am doing first, then do it. Not the other way around.

 

[psparky]

Ah yeah, much of that I have no idea about. I will definitely read up on it though!

I'm in a lab this semester that uses a lot of this stuff (I assume) but apparently the class (after speaking with the professor) is geared more towards using the equipment and writing the lab reports. The theory comes later he says.

This pains me a lot because I like to understand what I am doing first, then do it. Not the other way around.

Google the 7 or 8 things I talked about...read up on them...and ask questions.

 

[real10]

try to avoid doing something OVER and Over...focus more on understanding especially for EE & Math...understand and then do some examples for practice...
for example...understand what the Fourier transform really is (basically the series version converted to continuous...) though memorizing formulas speeds up things/calculations...

oh and BTW...u go to school to learn how to learn ... yeah use it sounds cool...FYI

 

[psparky]

Ok Budda...I'll start you out with the most basic electrical prinicipal with a sample circuit.

V=IR

Voltage = Current X Resistance.

Obviously, if you are given two of the three variables, you can find the third with simple algebra. Ok Good.

Let's take a simple 12 volt battery connected to a small light. As you know, you need two wires to the light...the positive and negative terminal of the battery to the light. Electricity will not work with one wire...or a return path.

Batterys are measured in volts.
Current is measured in amps
Resistance is measured in ohms.

So let's say I have a 12 volt battery connected to a light with a resistance of 100 ohms.

What is the current?

Well...V=IR.

So the current is .12 amps. Easy as that.

Ok, different circuit...lets say I have a random resistor of 10 ohms. It is also known that the current THROUGH the resistor is 2 amps. What is the voltage ACROSS the resistor.

Well...V=IR.

The voltage ACROSS the resistor is 20 volts.

Congratulations...you just successfully completed your first day of your first electrical class.

This V=IR is key. It will carry you through most of your college career. Make it concrete in your mind.

Absorb what I said...comment...and then I will teach you more if you like.

 

[BuddhaBelly34]

The only thing that concerns me is THROUGH/ACROSS. I am not sure I understand the difference.

Still Googling the topics you listed for your FE candidates. Trying not to overload my brain.

 

[psparky]

The only thing that concerns me is THROUGH/ACROSS. I am not sure I understand the difference.

Still Googling the topics you listed for your FE candidates. Trying not to overload my brain.

Good question...I'll try to explain.

When I take a volt meter and what to measure the voltage across a resistor...I take one terminal and place it on one side of the resistor and I take the other terminal of the volt meter and I place is ACROSS the resistor. So the positive terminal of the volt meter is on one side of the resistor...and the negative terminal is on the other side of the resistor. The votage reading is then taken ACROSS the resistor.

If I want to take an amp meter and find the current THROUGH the resistor. I need to disconnect a wire to the resistor...lets say the positive terminal of the battery. Now I need to hook this to the amp meter (which has two terminals or wires as well). Now I take the other wire of the amp meter and hook it back up to the original resistor. The current must now go THROUGH the amp meter.

Voltage is always measured across...current is always measured through...

Questions?

 

[psparky]

That's where the thru and across come from. Even when you are NOT using volt or amp meters and are just talking about the mathematics of a circuit...you still use the terms ACROSS and THROUGH correctly or you will sound silly!

If you don't quite understand yet...it's fine. As we cover more terms and concepts...it will become clear.

Also...as you can see...you math skills are more than adequate!

 

[psparky]

You are probably wondering the difference between voltage and current like most people do. I could explain in a complicated way...but instead I will explain in simple terms. Using a water example is good in my opinion.

Say I have a fire truck connected to a fire hydrant. Let's say this fire truck has an advanced control system for controlling water pressure and flow.

Ok...lets say they hook a garden hose up to it and simulate the flow you have at your house and they spray you in the chest. No biggy...your used to that.

Now let's say they increase the pressure of that same garden hose and spray you in the chest...it hurts much more. This is the same as increasing voltage! Increasing voltage is like increasing the "pressure" of a circuit.

Now let's say they go back to the original pressure of your garden hose...except this time they you going to use a garden hose that is 5" is diameter. Now when the hose gets sprayed at you...you get walloped by the massive water flow. This is the same as increasing current in a ciruit! More flow!

Now let's say I use the 5" garden hose with increased pressure and flow and hit you in the chest...you go flying backwards...This is the same as increased voltage and increased amperage! And incidentally...as you increase amperage...you need to increase wire size accordingly. Going to higher voltages will not increase wire size...it will only increase the insulation around the wire to keep the wire from arcing...or shorting.

This leads us into our next equation.

P=IV

Power = Current X Volts

Power is measured in Watts.

 

[BuddhaBelly34]

That makes perfect sense! I think I may have been measuring current incorrectly. With the above statement, if you measure current from one end of the resistor to the other you wouldn't get the same reading would you?

Damn my lab professor with his laissez-faire attitude toward teaching.

@ the second topic
Now it makes sense why amperage kills and not voltage. Increased flow of electricity allows the stopping of the heart, at even low voltages. So it's current = amount, voltage = intensity?

P=IV good lord I hope everything stays so easy.

 

[psparky]

That makes perfect sense! I think I may have been measuring current incorrectly. With the above statement, if you measure current from one end of the resistor to the other you wouldn't get the same reading would you?

Damn my lab professor with his laissez-faire attitude toward teaching.

@ the second topic
Now it makes sense why amperage kills and not voltage. Increased flow of electricity allows the stopping of the heart, at even low voltages. So it's current = amount, voltage = intensity?

P=IV good lord I hope everything stays so easy.

Correct...if you put the amp meter in parallel...you have effectively made a current divider...which doesn't tell you jack. The rest of your comments sound correct as well.

 

[psparky]

Here's another power equation...P=(I^2)*R. It's simply derived from plugging the V=IR into P=IV.

P=I*(I*R)

Also...(V^2)/R=P

Okay...KVL and KCL

Kirchoff's voltage law...Kirchoff's current law.

KVL...the sum of the voltages across the load or loads in a single loop equals the voltage source.

KCL...current in equals current out of a node.

 

[BuddhaBelly34]

This makes so much sense as to why I couldn't explain my results in my lab report. And I still got an A. I hate grades. They make no sense.

I speak with a lot of the Nepalese students in my classes and they tell me about their experience with school in Nepal. All I have to say is, holy crap. It's actually an accomplishment to pass high school there.

Okay, so with P=IV what does that tell us? Say a PSU for a PC. If I have a 650w PSU what does that mean? That it can send only a total of 650w (probably peak) across all of it's wires combined, or that it can send a total of 650w down each wire? Does what you say hold true for all PSUs?

Thanks so much for all of your help!

 

[psparky]

Lets talk about series and paralell. Let's use water for a teaching tool again.

When two resistors are in series...the water must flow thru one resistor...then thru the other resistor.

When two resistors are in parallel...the water must flow thru both resistors at the same time.

Capeche?

 

[BuddhaBelly34]

Got it.

 

[psparky]

This makes so much sense as to why I couldn't explain my results in my lab report. And I still got an A. I hate grades. They make no sense.

I speak with a lot of the Nepalese students in my classes and they tell me about their experience with school in Nepal. All I have to say is, holy crap. It's actually an accomplishment to pass high school there.

Okay, so with P=IV what does that tell us? Say a PSU for a PC. If I have a 650w PSU what does that mean? That it can send only a total of 650w (probably peak) across all of it's wires combined, or that it can send a total of 650w down each wire? Does what you say hold true for all PSUs?

Thanks so much for all of your help!

Not sure what a PSU is. But watts make more sense when calculated across a load...not thru wires or individual wires.

 

[psparky]

So let's finish up with the basics. First of all...when you have a voltage source with two resistors in series...the current thru the resistors is ALWAYS identical. If there is two amps thru the first resistor...there is two amps thru the second resistor even if their resistances are different. Once you find the current...You can then find the voltage across each resistor...and you will notice that KVL and KCL are satisfied...also that V=IR no matter how you slice it.

Series resistance...simply add the two resistors together to get there equivalent resistance.

Paralell resistance is slighter more complicated. (R1 X R2)/(R1 +R2)

 

[psparky]

Last two topics to complete your foundation for EE. Never forget this stuff!

Voltage division and current division.

When you have two resistors in series...they will often ask you what the voltage is across one of the resistors.

I'll say it two ways. When finding the voltage across a resistor in series with another resistor...take the resitor you are interested in and divide it by the sum of the two resistors...then multiply it by the voltage source.

Here's the same thing with term. If you are looking for the voltage across R1

Voltage source X ((R1/(R1+R2))= Voltage across R1

When all voltages are found...again you will find that V=IR...KCL and KVL are satisfied.

 

[psparky]

Current division is typically when you have a current source in parallel with two resistors in parralel. In other words...how much current goes thru each resistor. If both resistors are equal...current splits equally.

It's identical to the voltage division...except you take the resistor you are NOT intersted in...and divide by the sum of the two resistors.

If you want the current thru R1...Current source X ((R2/R1+R2))

It gets tricky...but if you take the currents you found in both branches and multiply by their resistors...the voltages will be equal! If the voltages are not equal...you did something wrong!

V=IR...KVL and KCL are satisfied.

Even in the dreaded AC...all these things are the same!

That's it for now. Master these concepts and you can pretty much get through 50% of your electrical engineering courses!
Practice, practice problems. Things will start clicking more and more!

 

[earlofwessex]

Very good explanations psparky!

Okay, so with P=IV what does that tell us? Say a PSU for a PC. If I have a 650w PSU what does that mean? That it can send only a total of 650w (probably peak) across all of it's wires combined, or that it can send a total of 650w down each wire? Does what you say hold true for all PSUs?

just to catch this, PSU is a power supply.
that 650W value should¹ be RMS, and it can supply a total of that when you add up all the loads². note that power is delivered over two wires, since it involves a voltage (which has to be between two places). almost universally in DC systems, the black wire is the return, called ground.
for eg: the potential difference will be between the Red and black wires, and the current will flow from the red wire through the load and back through the black wire (in the other direction, remember KCL?). these values give you your I and V for the eqn.

---
¹Marketing/sales people will use any figure they can to make something sound better
²Things are actually a little more complicated than this, but the concept is what's important at the moment.

 

[BuddhaBelly34]

Very good explanations psparky!


just to catch this, PSU is a power supply.
that 650W value should¹ be RMS, and it can supply a total of that when you add up all the loads². note that power is delivered over two wires, since it involves a voltage (which has to be between two places). almost universally in DC systems, the black wire is the return, called ground.
for eg: the potential difference will be between the Red and black wires, and the current will flow from the red wire through the load and back through the black wire (in the other direction, remember KCL?). these values give you your I and V for the eqn.

---
¹Marketing/sales people will use any figure they can to make something sound better
²Things are actually a little more complicated than this, but the concept is what's important at the moment.

Thanks for that. Yehp PSU = power supply unit. Also, note 1 is very laugh worthy. To the point that a certification process needs to be done on units to make sure they do what they claim.

And I'm still reading through everything sparky.

 

[psparky]

And I'm still reading through everything sparky.

Take your time. Considering I just gave you 50% of EE...Im guessing it's going to take a while to digest. You won't get the full understanding until you start working sample problems...and you start struggling and asking questions. That's where the learning takes place.

Oh ya...forgot one more basic. (There are several details for sure...but you have a good start) When you have batteries hooked up in series...the you simply add the voltages of the batteries. So two 12 volt batteries in series will deliver 24 volts. When you have two batteries in parallel...the voltage remains the same...just the batteries will last roughly twice as long.

One good definition of "in parallel"...is "the voltage across is the same." So whenever you have 2 or more loads (resistors) in parallel...the voltage will be the same across each load. If the voltage is not the same...they are not in parallel.

 

[BuddhaBelly34]

Take your time. Considering I just gave you 50% of EE...Im guessing it's going to take a while to digest. You won't get the full understanding until you start working sample problems...and you start struggling and asking questions. That's where the learning takes place.

Oh ya...forgot one more basic. (There are several details for sure...but you have a good start) When you have batteries hooked up in series...the you simply add the voltages of the batteries. So two 12 volt batteries in series will deliver 24 volts. When you have two batteries in parallel...the voltage remains the same...just the batteries will last roughly twice as long.

One good definition of "in parallel"...is "the voltage across is the same." So whenever you have 2 or more loads (resistors) in parallel...the voltage will be the same across each load. If the voltage is not the same...they are not in parallel.

I knew that about the batteries from doing some simple electronics stuff at home.

 

[SophusLies]

Considering I just gave you 50% of EE...Im guessing it's going to take a while to digest.

More like 5%. The EE students that I met in school were math and physics freaks. Some more math and some more physics but they certainly weren't just V = iR kids. They all knew a ridiculous amount of Fourier-stuff, complex analysis, vector calculus, PDE's (for Maxwell's equations), and probability.

I would not take EE lightly for math. I'm not trying to scare you but you're going to see some very serious math in an EE curriculum. When I saw the EE kids in my upper level math or physics classes they thoroughly impressed me with their talents. When I took set theory we had an EE kid that absolutely destroyed the class. When I asked him what he was doing to master the things in the class he told me he learned most of this stuff indirectly in his digital logic design classes, lol.

 

[BuddhaBelly34]

More like 5%. The EE students that I met in school were math and physics freaks. Some more math and some more physics but they certainly weren't just V = iR kids. They all knew a ridiculous amount of Fourier-stuff, complex analysis, vector calculus, PDE's (for Maxwell's equations), and probability.

I would not take EE lightly for math. I'm not trying to scare you but you're going to see some very serious math in an EE curriculum. When I saw the EE kids in my upper level math or physics classes they thoroughly impressed me with their talents. When I took set theory we had an EE kid that absolutely destroyed the class. When I asked him what he was doing to master the things in the class he told me he learned most of this stuff indirectly in his digital logic design classes, lol.

It doesn't scare me to learn upper level math, I just wanted to make sure that losing a negative sign now and again, or integrating one of the trig co-functions to be positive, etc... wouldn't be the death of me in the field.