what is another good book to study basics of circuits? (for electrical engineering student)

Thread Starter

Amr Moneer

Joined Jan 25, 2018
10
Hello

i've been looking for a good book to self-study the basics of circuits. i've been studying from 'fundamentals of electic circuit' but it's not so good so i'm looking for a replacement.. any suggestions?

i'm sorry if this is the wrong section but i don't know where to post this
 

dl324

Joined Mar 30, 2015
15,113
Welcome to AAC!

What makes the referenced book not so good? Is it too basic, too advanced? What is your knowledge level?

There's a text book section on this site. Have you checked it?
https://www.allaboutcircuits.com/textbook/

I've read that AAC educational information uses electron current which is backwards from what many practitioners use.
 

WBahn

Joined Mar 31, 2012
27,397
There are many books with the title, "Fundamentals of Electric Circuits", so that doesn't give us much of a clue. An author's name or ISBN number would really help.

As dl324 indicated, it's hard to recommend a "good" book unless we have some idea what you find "not so good" about this book. Also, we need to know what level of book you are looking for. There is a huge difference between a text suitable for a high school student that has yet to take algebra and an electrical engineering student that has taken differential equations.
 

Thread Starter

Amr Moneer

Joined Jan 25, 2018
10
full book name: Fundamental of Electric Circuits
Book by Charles K. Alexander and Matthew N.O. Sadiku

so what i don't like about this book is that the answers of problems in the back of the book are wrong. i've checked with simulation programs.
 

dl324

Joined Mar 30, 2015
15,113
so what i don't like about this book is that the answers of problems in the back of the book are wrong. i've checked with simulation programs.
Can you cite some examples and explain how your simulations disagree?

Simulators are only as good as the models they use and the people who use them. If you don't know what you're doing, circuits that won't work could appear to work. Conversely, circuits that will work might appear to not work in a simulator.

It's up to the user to sanity check simulation results.
 

WBahn

Joined Mar 31, 2012
27,397
If that's the only thing you don't like about the book, then just forget that it has answers -- many (most?) textbooks don't.

But, how sure are you that all of the answers are wrong? Are you sure that you aren't misinterpreting the questions and thus setting up simulations for a problem that wasn't asked?

Pick one or two problems and post them here. Then give what you believe the answer to be and what the book gives as the answer. Then we can explore the nature of the problem together.

I went and looked at the reviews on Amazon (and any web-based review is buyer beware). It has 59% 5-star rating and 75% 4-star and up. It has 8% 1-star and several of those mention issues with incorrect answers.
 

BR-549

Joined Sep 22, 2013
4,928
The BEST, FIRST, book to study electronics is........."Electronic Communication" sixth edition.....by SHRADER. On Amazon.....about 10 bucks. You will love it.
 

Thread Starter

Amr Moneer

Joined Jan 25, 2018
10
thanks Tako, BR-549 and dl324 for suggestions

If that's the only thing you don't like about the book, then just forget that it has answers -- many (most?) textbooks don't.

But, how sure are you that all of the answers are wrong? Are you sure that you aren't misinterpreting the questions and thus setting up simulations for a problem that wasn't asked?

Pick one or two problems and post them here. Then give what you believe the answer to be and what the book gives as the answer. Then we can explore the nature of the problem together.

I went and looked at the reviews on Amazon (and any web-based review is buyer beware). It has 59% 5-star rating and 75% 4-star and up. It has 8% 1-star and several of those mention issues with incorrect answers.
ok let's assume i'm going to forget that the book has answers. is there another easy way to check if my solutions are correct? that is important to me because i'm self-studying.
 

dl324

Joined Mar 30, 2015
15,113
. is there another easy way to check if my solutions are correct? that is important to me because i'm self-studying.
You could post any you're not sure about on the forum.

If you include the fact that it isn't homework, you can avoid having to answer obligatory questions because we don't do homework for students.
 

Tako

Joined Oct 21, 2014
65
Exactly. Start asking them one by one. Very often you can use a simulator to check your solutions in terms of circuits.
 

WBahn

Joined Mar 31, 2012
27,397
ok let's assume i'm going to forget that the book has answers. is there another easy way to check if my solutions are correct? that is important to me because i'm self-studying.
One of the beautiful things about most engineering fields is that the correctness of a solution can usually be verified from the solution itself. This is true even out in the "real world" where there are no answers in the book nor anyone to ask if your answer is right since, if there were, they wouldn't need to be paying you to solve the problem. So getting in the habit of verifying your answers on your own is an extremely valuable skill.

While the details certainly vary from problem to problem, the basic idea is that you assume that your answer is correct and use that to establish the rest of the circuit parameters and see if the results are consistent with the given information.

For a trivial example, let's say that you are asked to find the voltage output from a resistive voltage divider consisting of a 12 V source and with R1 = 100 Ω and R2 = 470 Ω (with the output taken across R2). You come up with Vout = 7.5 V.

Is this correct?

Assume that it is. That means that the current in R2 is

I_R2 = 7.5 V / 470 Ω = 15.96 mA

It also means that the voltage across R1 is

V_R1 = 12 V - 7.5 V = 4.5 V

This makes the current in R1

I_R1 = 4.5 V / 100 Ω = 45 mA

But since R1 and R2 are in series, you know that they must have the same current and since they don't, you know your answer is wrong.

Another way of checking your work is to solve the problem via a different route. This is particularly good when you are learning because it gives you practice using different techniques and lets you develop your own guidelines on when to use each. For instance, if you solve a problem using mesh analysis, then solve it again using nodal analysis or superposition. If the answers agree, then it is highly likely you got it correct.

Three other things you should get in the habit of doing are:

1) Estimate what you expect the answer to be. Any answer that is too far away from the estimate is immediately suspect and you need to determine whether it is your answer or your estimate that is in error. If possible, make bounding simplifications to establish upper and lower bounds on the answer. Now if the answer violates your bounds by any amount you know it is wrong. As an example, consider a classic wheatstone bridge configuration and you are asked to find the total current from the source driving the bridge. You can reduce the circuit to a simple to analyze one in two ways: First, replace the bridging element with a short. This will result in the greatest current from the source (assuming it's a voltage source). Second, replace the bridging element with an open. This will result in the lowest current. You final answer has to be between the two.

2) Always, always, ALWAYS track your units properly through each step of your work. We all make mistake and, more often than not, most mistakes we make will screw up the units -- provided they are there to get screwed up. When they do, you are in a position to immediately detect and correct your error.

3) Always, always, ALWAYS ask if the answer makes sense. This is related to the first habit, but goes further. If you answer is symbolic, ask if it reduces to what it should in the limit as various parameters go to extreme or critical values. Ask if there are values that drive it to zero or to infinity and ask if those results make sense. Sanity check it as many ways as you can.
 

WBahn

Joined Mar 31, 2012
27,397
You could post any you're not sure about on the forum.

If you include the fact that it isn't homework, you can avoid having to answer obligatory questions because we don't do homework for students.
He'll still have to jump through those hoops for a couple of reasons. First, one of the common tricks that students use to get someone to do their homework for them is to assert that it isn't homework. Second, the reason for the questions and for doing as little of the work as possible is less about not doing their homework than it is about helping the student learn the concepts. That is usually best done when the student does most of the thinking and the struggling and is just being guided by us.
 

Thread Starter

Amr Moneer

Joined Jan 25, 2018
10
One of the beautiful things about most engineering fields is that the correctness of a solution can usually be verified from the solution itself. This is true even out in the "real world" where there are no answers in the book nor anyone to ask if your answer is right since, if there were, they would need to be paying you to solve the problem. So getting in the habit of verifying your answers on your own is an extremely valuable skill.

While the details certainly vary from problem to problem, the basic idea is that you assume that your answer is correct and use that to establish the rest of the circuit parameters and see if the results are consistent with the given information.

For a trivial example, let's say that you are asked to find the voltage output from a resistive voltage divider consisting of a 12 V source and with R1 = 100 Ω and R2 = 470 Ω (with the output taken across R2). You come up with Vout = 7.5 V.

Is this correct?

Assume that it is. That means that the current in R2 is

I_R2 = 7.5 V / 470 Ω = 15.96 mA

It also means that the voltage across R1 is

V_R1 = 12 V - 7.5 V = 4.5 V

This makes the current in R1

I_R1 = 4.5 V / 100 Ω = 45 mA

But since R1 and R2 are in series, you know that they must have the same current and since they don't, you know your answer is wrong.

Another way of checking your work is to solve the problem via a different route. This is particularly good when you are learning because it gives you practice using different techniques and lets you develop your own guidelines on when to use each. For instance, if you solve a problem using mesh analysis, then solve it again using nodal analysis or superposition. If the answers agree, then it is highly likely you got it correct.

Three other things you should get in the habit of doing are:

1) Estimate what you expect the answer to be. Any answer that is too far away from the estimate is immediately suspect and you need to determine whether it is your answer or your estimate that is in error. If possible, make bounding simplifications to establish upper and lower bounds on the answer. Now if the answer violates your bounds by any amount you know it is wrong. As an example, consider a classic wheatstone bridge configuration and you are asked to find the total current from the source driving the bridge. You can reduce the circuit to a simple to analyze one in two ways: First, replace the bridging element with a short. This will result in the greatest current from the source (assuming it's a voltage source). Second, replace the bridging element with an open. This will result in the lowest current. You final answer has to be between the two.

2) Always, always, ALWAYS track your units properly through each step of your work. We all make mistake and, more often than not, most mistakes we make will screw up the units -- provided they are there to get screwed up. When they do, you are in a position to immediately detect and correct your error.

3) Always, always, ALWAYS ask if the answer makes sense. This is related to the first habit, but goes further. If you answer is symbolic, ask if it reduces to what it should in the limit as various parameters go to extreme or critical values. Ask if there are values that drive it to zero or to infinity and ask if those results make sense. Sanity check it as many ways as you can.
I will definitely try that. Thanks so much!!
 

Max Derton

Joined May 3, 2018
11
I would recommend Practical Electronics for Inventors, it's $20 on amazon, over 1000 pages and is a very good intro to electrical engineering! I should also mention it does use calculus to explain somethings (but it does give you the basic algebraic equations).
 

bertus

Joined Apr 5, 2008
22,095
Hello,

Here is an other source for the NEETS series and more:

The US Navy Electricity and Electronics Training is already known and posted by @JoeJester in his signature:
https://murdercube.com/files/Electronics/Electronics/US_Navy_Electricity_and_Electronics_Training/
There is also the US Navy Electronics Technician series:
https://murdercube.com/files/Electronics/Electronics/US Navy Electronics Technician/
And the US Navy Information Systems Tech Training:
https://murdercube.com/files/Electronics/Electronics/US_Navy_Information_Systems_Tech_Training/

Bertus
 
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