General understanding of electronics....

[Joe Black]

Hello there, everybody.
My first impression with badcaps is excellent, I wonder how I haven't ended up here before. Keep it up.

My question is this, and feel free to move if needed:
Where can one find a good electronics "lessons" or something along that line.
Here's the problem: there are many sites where you can learn about electronics, but it all comes to symbols and what each component role is.

I have repaired many devices and computers for friends or family, but what I want is to understand a circuit, and I don't know how to go about that.

I believe a lot of people is in similar position; yes I can test a FET and replace it, but how and why the driver drives it? -No clue.
Yes, I know exactly what a graetz is and what it does. Why it has a resistor here and there? No clue.

So, just a thought here, and if anyone can share their experience I'll be grateful.
Do you think about circuit as a flow of electrons? Does your electron go from positive to negative or contrary?

Hope I made any sense. Thanks in advance.

[joshnz]

Re: General understanding of electronics....

I Learnt from books at my school library.

[SteveNielsen]

Re: General understanding of electronics....

A lot of stuff is online for free. Do a search for basic electronics and start browsing the tutorial/education/lesson sites, find one that suits you then dig in

I learned initially from books, classes and on job training/experience but I've learned even more since from online sources. This forum is a good place to learn from, I learn quite bit just from reading others' posts as well as asking questions. When I come across a term or whatever I don't understand I look it up.

Somethings may take a while to "click" in your head but they will if you keep at it.

[budm]

Re: General understanding of electronics....

Do you have example circuits that you are trying to understand how it works? Start with simple one first.

[fzabkar]

Re: General understanding of electronics....

I have repaired many devices and computers for friends or family, but what I want is to understand a circuit, and I don't know how to go about that.

SteveNielsen's situation pretty much mirrors my own. I would add that I learned a lot from colleagues who were many years my junior, and who had lesser academic qualifications, and I'm forever grateful for their patience and tutelage.

Do you think about circuit as a flow of electrons? Does your electron go from positive to negative or contrary?

I always think in terms of current, which is the flow of positive charges, not electrons.

If you wish to get into microcontrollers and programming, then I recommend the PICAXE. It is very cheap (< US$5) and is programmed in BASIC. There are plenty of simple projects that could get you up to speed very quickly.

[momaka]

Re: General understanding of electronics....

Like SteveNielsen and fzabkar, my knowledge too is both from formal (university) training as well as learning by myself online and taking things apart.

Where can one find a good electronics "lessons" or something along that line.
Here's the problem: there are many sites where you can learn about electronics, but it all comes to symbols and what each component role is.

Any online source is good. The hard part is knowing what you need to learn. The difference between formal university training and learning yourself really is that in a university, they just have everything you need to learn organized for you step by step. But if you know what to learn, then you actually need not go to a university to learn the stuff.

When it comes to circuits, many (university) books start by first introducing what potential (voltage) and current are. Then, they get into simple DC circuits with only power source(s) and resistors in various parallel and series configurations. The idea is to become expert at simplifying the parallel and series connections in a circuit to find all of the currents and voltages. Next comes capacitors and inductors. You learn how they affect current flow in the circuit, as well as how they add up when in series and parallel. From there, you learn how to calculate circuit time constants and impedances. To calculate impedances, you need to know complex math (which, despite its name, is not complex at all - just need to know a few basics of trigonometry). Once you know how to calculate impedances, you are on a whole new level now because you can get into AC circuits as well (which includes power distribution systems as well).
Finally comes semiconductors... first diodes and simple power supplies, then you get into transistors and eventually amplifiers. Once you have these basics, you are pretty much set to tackle just about any analog circuit.

Now, if you want to learn digital circuits, digital logic, and microcontrollers, that's a whole different area. For those, usually you first start with the different numbering systems (i.e. binary, hex, octal, and how they are related to the decimal system). Then you learn about gates, then latches and flip-flops, and eventually you jump into microcontrollers.

With that said, hopefully you have an idea in what order to learn things now .

[fzabkar]

Re: General understanding of electronics....

I also have a university degree (electrical engineering), but I followed it up with a lot of practical experience, and I then supplemented it with top-up courses at the local technical college. I don't know what it's like in Europe or the USA, but in Australia the TAFE courses are/were heavily subsided by the government, so that the cost was of the order of a few hundred dollars per course.

[Joe Black]

Re: General understanding of electronics....

When it comes to circuits, many (university) books start by first introducing what potential (voltage) and current are. Then, they get into simple DC circuits with only power source(s) and resistors in various parallel and series configurations. The idea is to become expert at simplifying the parallel and series connections in a circuit to find all of the currents and voltages. Next comes capacitors and inductors. You learn how they affect current flow in the circuit, as well as how they add up when in series and parallel. From there, you learn how to calculate circuit time constants and impedances. To calculate impedances, you need to know complex math (which, despite its name, is not complex at all - just need to know a few basics of trigonometry). Once you know how to calculate impedances, you are on a whole new level now because you can get into AC circuits as well (which includes power distribution systems as well).
Finally comes semiconductors... first diodes and simple power supplies, then you get into transistors and eventually amplifiers. Once you have these basics, you are pretty much set to tackle just about any analog circuit.

Now, if you want to learn digital circuits, digital logic, and microcontrollers, that's a whole different area. For those, usually you first start with the different numbering systems (i.e. binary, hex, octal, and how they are related to the decimal system). Then you learn about gates, then latches and flip-flops, and eventually you jump into microcontrollers.

This. Thanks a lot, guys. Well, I'll likely follow this for a beginning, and will make a thread somewhere for a lot Qs to come...

You all seem like a bunch of really helpful people... Old school lives

[momaka]

Re: General understanding of electronics....

I also have a university degree (electrical engineering), but I followed it up with a lot of practical experience

+1

University courses are good for the theory, but the labs can be skimpy on some practical stuff or the theory may be a bit "disconnected" from the labs. And in general, it takes time to connect the theory in the books with the practical everyday circuits you see in electronics. But just keep at it and research whatever you don't understand. Many times you will be over your head, but that is normal. Eventually, you will get it. Sometimes, you might have to come back and re-read what you read before to get a better understanding.

Also, I think the easiest things to start on, in terms of practical circuits that you can understand, is those cheap PC PSUs. Read up on this article:
http://www.hardwaresecrets.com/anato...ower-supplies/
and try to trace the circuits on your power supply (in particular, the power-related components... don't worry about any logic and controllers, you will get to those later.) Look up some of the older crappy PSU rebuild threads - many contain lots of good info.

[ahendricks18]

Re: General understanding of electronics....

I learned from experience working on old computers rescued from recycling. Taking them apart and upgrading, repairing, etc. I do have an old book from the 1960's on electricity and electronics. I think its called "A first electricity book for boys" or something. Has some good info in it.

[keeney123]

Re: General understanding of electronics....

As you can see there are many ways to learn electronics. I guess it is which way works best for you and how deep of an understanding you might want to have. If you want to design a analog circuit a school would be a way I would go, like a Engineering School. Designing digital circuits one could get by with knowing algebra, Boolean algebra, etc. To troubleshoot already designed circuits I would say the best one could do is with a Associates Degree in Electronics. However, one can also learn as they go. So you could learn by doing. I have seen technicians that have learned this way. If you want to learn by the latter I would say this forum would work. If you what to learn by the former I would say this this forum could help you through the school of your choosing.

Most engineer I know think of what is called hole flow or positive to negative. As a technician I learned of electron flow in school, negative to positive. I was also taught hole flow because engineers think that way. "I" also found that engineers are not as good as electronic technicians to troubleshoot already designed circuits, unless there is a problem with the design. The reason "I" found this to be true is that the technician thinks more abstractly. By this "I" mean a engineer will be looking for some logical solution to a problem. Where a technician will be looking for any solution to the problem. So if a capacitor is connected across address lines and some assembler stuffed a socket on top of that cap most engineers would not think that was a possibility.