Electronic circuit design question

[ProviaFan]

First, this post might not be of such a highly technical nature that it deserves to be in the ATHT forum, but in my estimation, to post it in ATOT would be to invite a hoard of nefs and very few (if any) useful answers. Thus, I chose to post it in this forum, with the hope that the Moderators agree with my aforementioned assumptions, or at least that they will refrain from moving this thread to ATOT or nuking it.

This post will also be short and to the point, since I just got done with a typing marathon on another post in a different forum. Anyway, I have virtually no knowledge at all about the inner workings of electric circuits, nor how to build such things, but have become interested in the inner workings of such things, and have developed a desire to build little gadgets and interface them with my computer (possibly through the parallel or serial ports, as I have heard that this is probably the easiest way to accomplish that goal).

Because I'm homeschooled, and my parents haven't studied in the fields of electronics, I can't just get in some kind of class about it. Thus, I appeal to the AnandTech members who visit this Highly Technical forum, to please inform me in the following. With what methods did you learn the basics of electronic circuits; with what books or online resources were you taught? Or did you teach yourself? If you could provide me with some basic links or references to get started on this pursuit, I would be greatly appreciative. Thank you and good night.

 

[Mday]

Hello, there. I am currently an undergrad EE major. Unfortunately, I cannot recommend any of the books that I have to you since they are not that good. I have ones that are good are beyond what you need.

I recommend going to a local school, and asking what books the teachers there can recommend. Or going to a college and asking the same thing. What you will want to do is basically start with freshman level physics, and work there.

This is actually one of the reasons why I cannot support home schooling for the most part. If you are old enough, you may be able to take classes in a community college to learn things. Some schools allow home schoolers to take specific classes at their schools, such as natural sciences (chemistry, physics, and biology) and math.

Now for an important question, how much math and physics do you know?

 

[ProviaFan]

Originally posted by: Mday
Hello, there. I am currently an undergrad EE major. Unfortunately, I cannot recommend any of the books that I have to you since they are not that good. I have ones that are good are beyond what you need.

I recommend going to a local school, and asking what books the teachers there can recommend. Or going to a college and asking the same thing. What you will want to do is basically start with freshman level physics, and work there.

This is actually one of the reasons why I cannot support home schooling for the most part. If you are old enough, you may be able to take classes in a community college to learn things. Some schools allow home schoolers to take specific classes at their schools, such as natural sciences (chemistry, physics, and biology) and math.

Now for an important question, how much math and physics do you know?

In math, I have had much algebra (I completed Saxon Algebra II last school year, and am doing Advanced Math this year). Thus, I also have had some trig. However, no calculus (I figured that that was going to be a problem, guess my electronics studies will have to wait). Also, I'm only in 10th grade, so I haven't had any physics yet.

 

[blahblah99]

First of all, I would recommend learning the mathematics behind the EE theory. This includes knowing full well trig, geometry, calculus, advanced calculus, series, and linear algebra. On top of that, you will also need to know how to do fourier transforms, laplace transforms, inverse laplace, z-transform, and bode plots.

Now with that said, if you can make it through that without squirming, then you will be ready to tackle the real courses.

Which usually starts out with basic circuit theory dealing with Ohm's Law, Kirchoff's law, Thevinen/Norton's equivalent circuit, bode plots, voltage sources, current sources, and charging/discharging capacitors and inductors with DC voltage sources and switches.

After basic circuit theory, you'll get into AC voltage sources and will deal with phase, more bode plots, laplace transforms, low and high pass filters, filter response and properties.

Next up would be a course in active devices, starting with a quick intro to P-N junctions and their properties, then to diodes and their characteristics. Then comes npn and pnp transistors - you have to learn their properties and how they work. After that you will learn how to bias them for different regions of operation (active, saturation, or cutoff), then small signal analysis with equivalent models and common amplifier configurations of transistors (emitter follower, common emitter, or common base mode).

After you understand the npn/pnp trans, you also have to learn the P-ch and n-ch FETS, which behaves similarly to the npn/pnp devices but have slightly different behaviors.

With an understanding of active devices, you'll then learn how to use them in various circuits such as amplifiers, oscillators, current sources, buffers, logic circuits, switches, etc. You'll also learn about the concept of FEEDBACK, frequency compensation, and multi-stage amplifiers.

Once you get to that level, you will pretty much be able to understand how any circuit works if you have the schematics. As for circuit design, that is based on how passionate and creative you are with circuits.

Some people like analog, others like digital, and some like both. I like both, but I'm mainly into analog circuit design. My current hobby project is designing a 400W single channel car amplifier in as small a package as possible.


As for resources from which you can learn, I would recommend these two books, "Basic Circuit Analysis" and "Microelectronic Theory", both hardbooks.
And the best way to learn is to go to Cadence.com and download their student edition software of Orcad. It is a virtual breadboard that'll simulate circuits with surprising accurate results.

<------------ graduated with a B.S. in EE at UCLA in June 2002.

 

[Mday]

that's what i feared, you will not get too far without calculus. for example, you cant explore much into capacitors and inductors due to the use of differential equations. but those are just for background information.

as you get higher and higher into circuits, with transistors and other active components, there will be "assumptions" and "estimates" being made which make the equations more simplified, by it's good to have some background in the higher level math classes.

For now, see what you can do about learning some calculus.

but keep this thread bookmarked, many of us will help you.

 

[ProviaFan]

Thank you all for your helpful input. It seems that I just don't know enough at this point to try to learn this stuff, so I'll try to concentrate on improving my math skills first, and save this thread for future reference in a few years once I've learned some more trig and some calculus.

 

[Geniere]

jliechty - As I understand your post, you wish to achieve a basic knowledge of electronics. You can be very comfortable in electronics without having knowledge of higher math. Trig and boolean are probably necessary for a limited understanding. There are many home study college courses available (some grant degrees) if your parents can afford it.

Regards

 

[Insidious]

Originally posted by: Geniere
jliechty - As I understand your post, you wish to achieve a basic knowledge of electronics. You can be very comfortable in electronics without having knowledge of higher math. Trig and boolean are probably necessary for a limited understanding. There are many home study college courses available (some grant degrees) if your parents can afford it.

Regards

I agree here on both counts.

first:

I was first exposed to electronics in the USN and had no calculus background what so ever. As a matter of fact, I didn't even know the difference
between a volt and an amp when I joined.

Algebra is a MUST, but the rest is gravy unless you are going for a credential... then you need the math (but that training would be part of the credential).

Following 6 years as an electronics technician / Reactor Operator in the USN, I went on to earn a BSEE from Purdue and feel I am well qualified to
offer up the preceeding opinion.

Second:

I feel a training program is the most effective path to electronic circuit design understanding. whether that be a web based, technicial school based, or college based.... that is a matter of your goals, preferences and resources.

Good luck dude.... It is a potentially rewarding and challenging endeavor

-Sid

 

[unclebabar]

if you were my kid, I'd probably go to toy-r-us, radio shack, or if you live in a major metro area The Science Company (?) or some such place where they sell educational toys at <lengthy editorial omitted> prices and get you a electronics kit, such as 'make your own radio' or 'build your own rs-232' interface ... assuming you really don't know anything about electronics.

or being cheap you could pick up some plans for what you want to build on the internet and pick up the parts at a wholesaler. you won't get clever/educational side notes in the instructions (such as 'this works because according to Ohm's Law blah blah blah')

 

[drag]

My best guess would be learn-by-doing. Start off building stuff, do what you want. Get idea figure out how to acomplish it, work your way up from there. take classes to fill in the missing blanks, but while you are learning your math there is no reason why can't learn to build curcuis at the same time, hell if you are able to apply your math to your curcuits as you progress in your studies you will learn both much quicker!
If you wait to study electronics only after you learn math you will waste a lot of time. There is alot to learn before you ever get to the point were you will need calculus. Most electricions can't even add correctly, that high order math stuff is only needed in curcuit design, so it will be awile before you get to that point.
IMHO home schooling has given you a leg up on it, because you know that you can do stuff on your own free will and don't have to depend on instutations. There are a lot of people out there that know a lot more than most college professors about electronics and they never set one foot in a classroom. I am not trying to say that school is a bad thing, college is a definilty a good thing and will help you out immensly. If you look at inventors and designers that were truly successfull you realise most of it comes down to will power and hard work, not your schooling.

Remember, No time like the present!

 

[blahblah99]

When it comes to circuit design, there are two ways to approach a problem:

1) Hack and slash method. Plugging and chugging different components until you achieve the desired results. Although this may work for simple circuits, it may (and almost always) produce unexpected results in more complex circuits.

2) Mathematical method. Much more complex way to approach a problem, but you get a deeper understanding of how a circuit works, so you'd be able to predict what the response of a circuit would be due to a variations on the circuit.

Since you just want to study electronics for your own good, I would start with simple hobby circuits and read through the circuit operation details. If you really do want to get involved with circuit design, the books that are on the top of my list are:

"Basic Circuit Analysis" - don't remember the author, but it's a common university/prentice hall book. Hardcover
"Analog Signal Processing with LaPlace Transforms and Active Filter Design" by Don Meador
"Microelectronic Circuits" by Sedra and Smith. <------------ my all time favorite
"Art of Electronics" by Paul Horowitz, also an excellent reference book.

 

[JSSheridan]

The parallel port on a computer is fairly easy to interface once you have a wiring diagram of the input and output pins. Then you can learn assembly language and write programs for MASM. You can easily run some simple digital circuits off the parallel port this way, like turning LED's on and off. You can move up to C++ or J++ after that and get into some real complex uses for it later on. I would suggest that you find a good digital logic text to study to complement the programing text also.

The other area two areas of electronics are amplifiers and power electronics, which are analog studies, but I understand you question to be more closely related to computers and digital circuits. This is a good beginning. It will be better when you begin to understand, what you do not understand. Good luck. Peace.

 

[RaynorWolfcastle]

blahblah99, with all due respect, you cannot possibly expect a 10th grader to use laplace transforms and solve differential eqns.

jliechty, before you get into circuit design, you'll want to go through the following steps.
1) Learn basic physics, they're always a useful background (Newton's laws and such)
2) Learn the physical basis of basic electronic devices
3) Learn a bit of circuit analysis of purely resistive circuits (Ohm's law, mesh and nodal analysis, Thevenin and Norton equivalents should be doable even without calculus)

For anything more advanced thant that you will need calculus. Try and look in a general physics book they usually have at least a small part about the basics of resistive circuits (I know I learned basics of resistive circuits in 10th grade).

 

[cressida]

jliechty,

A lot of the advice posted in here, is really useful. Not too long ago, I started learning basic circuits and circuits analysis myself.
I would recommend for you to look into purchasing books that teach you basic basic circuits. Also, head to radio shack, get yourself a multimeter, some resistors, and breadboard. Look at examples in books for some very simple circuits, and try to simulate them yourself and learn the basic rules and concepts. (Ohm's Law, Kirchoff's law). Once you have taken math classes such as, Calculus, then you can start to look at more advanced circuits, such as circuits with capacitors and inductors. For now try to keep things simple and make circuits with resistors and any battery.

I hope this helps, please feel free to PM.

 

[KilroySmith]

Hey guys, relax.

It really isn't all that difficult. I built a lot of stuff at a young age with none of the math background you're talking about. Sure, one is limited in the types of circuits one can designed, but you can still have a blast with really, really basic stuff.

The best way I could imagine to learn the basics is to get the $50 "basic electronics" kit at ToysRUs, Radio Shack, etc., and a $15 radio shack multimeter. Lots of basic parts, a book with lots of experiments using the parts, and lots of basic practical theory. Once you are confident in putting together a battery, resistors, capacitors, speakers, switchs, light bulbs, and those magic elements called transistors to create lights that turn on and off, ungodly screeches, moisture detectors, and the like, you have a much better basis for buying (or building) little projects - either the prepackaged ones that you can buy for $15-$20, or ones that you can find with a quick search on the web. If you find this to be interesting, you'll quickly start figuring out how to start connecting more complex things together (for example, you'll find that you can go a long way with the cookbook circuits that manufacturers publish in the documentation for their parts). You don't really need to know differential equations to build a cool little battery charger using a chip from Maxim - They give you the simple circuit (once you learn how to interpret it), and all you have to do is implement it.

You'll find out whether or not this really interests you; then the heavy theory becomes a requirement. Until then, decide to have fun instead.

/frank

The search engines are a great help here; searching for something like "Basic Electronics tutorials" can send you off on an afternoon of finding good stuff. I have seen some excellent pages for basic tutorials, but can't find the links at the moment.

 

[Belegost]

Just a suggestion, if at all possible, get yourself down to a local community college. The cc's are very good about allowing high school students into the classes, I would suggest getting into the college algebra course over the summer. (It's stuff you've done, but it gives good review and builds your confidence.) This lines you up for precalculus in the fall, and first semester of calculus by spring of next year.

I'm currently an undergrad EE major, and I was home-schooled through high-school, I used the community college to fill various requirements (foreign language, art, etc.) but never thought of going through math there, I wish I had, I would have saved a lot of time in college.

However, don't despair of understanding this material without the math and physics, I recommend Getting Started in Electronics by Mims, which is usually found at Radio Shack for <10$. It's rather friendly to those just getting into the field, but very accurate. (accurate enough to be on the recommended reading list for Intro to EE class at UCSD) Read through that or some of the entry level material mentioned elsewhere in this thread, and then get a breadboard, a decent multimeter, head over to jameco.com and pick up some of their grab bags of parts (you can't beat 3lbs of various parts for $20) and starting putting together simple DC circuits. You can find a wealth of information about circuit designs around in books, or periodicals, as well as on the web. Once you've got an intuitive grasp of how things sort of work, make some goals of circuits functions you want to reach, and start working towards them.

Despite what some may think, an intuitive, practical understanding of how components and circuits operate is just as important as the theoretical knowledge and heavy planning with mathematical models. Start getting the experience now, and then flesh it all out with theory later.

Oh, and I was thinking back to the intro EE books we used: avoid anything written by Rizzoni like the plague, the guy has no idea how to write, provides incorrect solutions to over half the problems, and his books are often referred to as tomes of confusion by those who have read them.