Okay, so I came up with a fourth item. 6 One of my engineering instructors (we’ll call him Chuck 7 ) taught me a secret that I would like to pass on. Almost every discipline is easier to understand than you might think. The secret pro- fessors don’t want you to know is that there are usually about fi ve or six basic principles or equations that lie at the bottom of the pile, so to speak. These fundamentals, once they are grasped, will allow you to derive the rest of the principles or equations in that fi eld. They are like the old simple Legos®; you had fi ve or six shapes to make everything. If you truly understand these few basic fundamentals in a given discipline, you will excel in that discipline. One other thing Chuck often said was that all the great discoveries were only one or two levels above these fundamentals. This means that if you really know the basics well, you will excel at the rest. One thing you can be sure of is the
human tendency to forget. All the higher-level stuff is often left unused and will quickly be forgotten, but even an engineer-turned-manager like me uses the basics nearly every day.
Since this is a book on electrical engineering, let’s list the fundamental equa- tions for electrical circuits as I see them:
■ Ohm’s Law
■ Voltage divider rule
■ Capacitors impede changes in voltage
■ Inductors impede changes in current
■ Series and parallel resistors
■ Thevenin’s theorem
We will get into these concepts in more detail later in the chapters, but let me touch on a couple of examples. You might say, “You didn’t even list series and parallel capacitors. Isn’t that a basic rule? ” Well, you are right, it is fairly basic, but it really isn’t at the bottom of the pile. Series and parallel resistors are even more fundamental because all that really happens when you add in the caps is that the frequency of the signal is taken into account; other than that it is exactly the same equation! You would be better served to understand how a capacitor or inductor works and apply it to the basics than to try to memorize too many equations. “What about Norton’s theorem? ” you might ask. Bottom line, it is just the fl ip side of Thevenin’s theorem, so why learn two when one will do? I prefer to think of it in terms of voltage, so I set this to memory. You could work in terms of current and use Norton’s theorem, but you would arrive at the same answer at the end of the day. So pick one and go with it.
You can always look up the more advanced stuff, but most of the time a solid application of the basics will force the problem at hand to submit to your engi- neering prowess. These six rules are things that you should memorize, under- stand, and be able to do approximations of in your head. These are the rules that will make the intuition you are developing a powerful tool. They will unleash the simulation capability that you have right in your own brain. If you really take this advice to heart, years down the road when you’ve been given your “pointy hairs ” 8 and you have forgotten all the advanced stuff you used to know, you will still be able to solve engineering problems to the amazement of your engineers.
8 In case you have lived under a rock for the last few years and missed a certain very success- ful engineering cartoon, this means “ promoted to management. ”
CHAPTER 1 Three Things They Should Have Taught in Engineering 101
26This can be generalized to all disciplines. Look at what you are trying to learn, fi gure out the few basic points being made, from which you can derive the rest, and you will have discovered the basic “Legos” for that subject. Those are the things you should know forward and backward to succeed in that fi eld. Besides, Legos are fun, aren’t they?
Thumb Rules
There are a few rules in any discipline from which you can derive the rest. Learn these rules by heart; gain an intuitive understanding of them. Most signifi cant discoveries are only a level or two above theseEvery discipline has fundamentals that are used to extrapolate all the other, more complex ideas. Basics are the most important thing you can know. It is knowledge of the basics that helps you apply all that stuff in your head correctly. It doesn’t matter if you can handle quadratic equations and calculus in your sleep. If you don’t grasp the basics, you will fi nd yourself constantly chasing a problem in circles without resolution. If you get anything out of this text, make sure that you really understand the basics!