GUIDE: How do I electronics?! - Page 1
Forum section: electronics / beginners

author: RazSlack
author_rank: Contributor
timestamp: June 20, 2014, 08:19:44 pm
content: Hey folks! I decided to write up a little how-to-electronics guide here for those new to the whole thing but willing to get into it, either for hobby, studies, or work.Step 1, getting the knowledge:Sure enough, replacing blown fuses, bulging caps or burned resistors is easy enough. You replace things you can see that are damaged, put the whole thing together, connect it to mains, and boom again, you choke on silicon smoke.Knowing that a component is damaged is one thing, but that's not the beauty in this field. So next time you fiddle with something, ask yourself the question: WHY did the fuse blow? WHY do the caps bulge? WHY did those resistors burn?Even a kid can check a fried transistor, but knowing why the transistor fry is the big thing. To answer the questions, you need measuring, consulting with the schematics, using your senses, or common sense, etc.Studying in the field of electronics REALLY helps out! It is a serious decision, but it pays off for the devoted. Personally I have finished in a school that had electronics courses, and it served as a foundation for my knowledge. If you don't study electronics, it's tough deal, but can still be managed without it for a certain degree.If you're not in school, or not willing to take courses of electronics, at least looking up on some basic theories should be done, like:Ohm's law (the relation of volts and amps)Kirchoff's laws (the way current flows and voltage is applied)Thévenin-Norton-theorem (simplifying DC circuits for easier calculation)Fourier's law (modelling any signal as a sum of sine waves)Shanon's law (basic theory of digital signal encoding)etc.After being sure of knowing how electronics works, the next thing should be understanding basic building block circuits, like:Basic resistor, capacitor and inductor networksvoltage and current dividersfiltersoscillatorscurrent mirrorscommon emitter amplifiersdifferential amplifierscomparatorsetc.So much to learn, so little time...Step 2. Getting what you need to use your knowledge.Okay, now you know how stuff works, you brag about to your friends how much you know about electronics, sooner or later, a few devices might end up on your desk that your friends asked if you could fix for them. You are eager to take stuff apart, and check out how it looks from inside, you open it up, and you don't see a damn thing. What do you do?Well, gotta measure!To measure, you need stuff that can do it! Dave already has a video on good equipment to get, here it is:Yeah it's a lot of stuff, I know, but you don't need all for now. Just a basic set. Here's a quick, budget way to get a nice electronics labON THE FLY."ON THE FLY" is the critical thing here. You should buy things that you actually NEED, not what you actually WANT. A 20 GHz digital spectrum analyzer will do you no good if you don't know what to use it for, or you can measure things you need through other means.So. What should you get?A basic set of tools, like screwdrivers, scalpels, files, soldering iron, blah blah.Equipment you can use to hack. If you have this, you can do basic repairs like torn wires or blown fuses. A good tip here: Many useful stuff can be aquired in medical instrument shops. Tweezers, scalpels, things like this can be bought for cheap in medical equipment shops. By cheap I mean really cheap. Don't shop on eBay for stuff you can buy locally!Multimeters.With one, you can measure lots of stuff. Once you add a second one, stuff you can measure increases dramatically. You can measure power directly, make function figures, etc. Two meters are not entirely needed, but highly recommended.A power supply.Once you add a power supply to your arsenal, your access grows exponentially. You can begin doing any project you want pretty much, since almost every project needs power to function, you must get, or build one. I prefer the way of building a linear power supply. It helps understanding how they work, you'll be working with power supplies a lot anyway!Breadboard, or some other way of quick prototyping.This is where the big experimenting comes in, now you can actually build sample circuits like the building blocks I explained before. Build them, measure them, study them, understand them! If you have made an interesting (permanent, veroboarded) sample circuit, don't throw it away after understanding how it works! Put it away, and label it, so that you may reuse it later.An analog oscilloscope.This is where you stop growing a bit. Oscilloscopes are a big investment, and they might be rarely used in basic things, but when you need one, then you need one. As Dave suggested in his videos, a standard 20MHz dual-trace analogue scope works pretty darn well for the things you need it. The key is: Analog! You learn so much more with an analog scope than a digital one (and it's cheaper as well). Period, just get one.Now we all know that oscilloscopes are the funky stuff here, you get to turn pots and look like a pro while doing so, all the knobs and switches and terminals and stuff... So tempting to get one right now! Just don't buy it first. A multimeter is much more useful than a scope if you're a beginner, you cannot measure as much stuff with a scope than with a multimeter. (technically you can, but if you have the knowledge to do so, you'll understand that it's easier done on a multimeter than on a scope)On a quick note here:If you're working or studying in an area that has electronics labs, they frequently throw obsolete test gear away. THIS is the wet dream of a beginner hobbyist! In my school, they toss out perfectly working old scopes and bench power supplies so another company disassembles and sells them for garbage metal price! Ask around with your boss, teacher, or whatever. Maybe you'll get some of the gear for free (or you can trystealingacquiring them trough cunning ways if they aren't willing to give them to you and you have the guts for it. They'll end up in a scrapyard anyway, why don't they give them to the eager students who are willing to use them? Bah, bureaucracy.)Step 3. Going digital.After all this, you can pretty much start repairing amps, power supplies, and some other gadgets. You have some basic stuff to hack and repair with, you understand why stuff breaks, you can fix them quick and easy. You might stop here if you want, as many people enjoy repairing more than actually building.But if not, then let's proceed, so let's sum what you have so far:First off, you have the knowledge! A very important, and difficult thing to get, congrats!Second, you have a basic electronics lab consisting of:A set of work toolsOne or two digital multimetersA linear power supply (that you made, possibly)An analog dual-trace oscilloscopeSome breadboards, or veroboardsBasic building block circuit prototypes that you understand how they workYou might have noticed that I haven't talked much about the digital aspects of electronics too much. It's because I believe electronics has a specific learning pattern, that starts with everything analog, and then going to digital. If you start digital, you might have no idea why a basic logic circuit doesn't wish to work at all.The only difference between analog and digital is that you associate logical values to certain voltage levels, the digital circuits still need a power supply, they still use resistors, capacitors and transistors, also when you measure them, you'll most likely do it with a multimeter or oscilloscope, and all that stuff is still analog. Without analog knowledge, digital doesn't do much good.Anyway, if you're into prototyping and things like that, it should be high time to get a feel on basic CAD-CAM and EDA programs. You're gonna be doing projects, so having a PCB design suite, a circuit simulator, and some other design automation program is rather important. Now there's one thing to watch out for here, and this is very important, so I'll put it all in capitals and write it in a seperate line:DON'T USE THE SAME PROGRAM FOR ALL YOUR CAREER!Sounds weird, eh? Well, this might be my own stupid opinion, but personally, I have used Protel for Windows (the original old version), Protel 99SE, Altium DXP, Abacom Sprint-Layout, GNU gEDA, and am currently using DIPTrace. After a few projects, I'll switch to Eagle. So why switch the packages all the time? Primary reason for that is to stay away from fanboyism. You show your board to a fellow electronics engineer, he'll give you an honest opinion. You tell them you made it in a package different than what they use, and they suddenly act like spanish inquisition, even taking back their previous compliments, saying your board is suddenly shit, just based on what package it was designed in.Every package has good and bad sides, and you might like one's features better than the other. If you keep switching, you'll have a broader idea of what certain packages can do, and you can decide what you feel comfortable with.So what about them micros?Start learning assembly. To know how assembly works, you need to know how a processor itself works. For that, you need to know how logic circuits work. Logic circuits are made of transistors. See? Analog stuff! Complex electronics is built upon simple stuff that you should already know.PICk a microcontroller brand. See the pun? PICs are somewhat simple to get into, and can teach you a basic programming logic, but I heard arduinos are pretty nice, though I haven't touched them yet. You wanna build your own retro computer? Check out the Z80 or 6502! Get in touch with certain microprocessors and microcontrollers, this is the biggest step in digital electronics that literally has UNLIMITED potential in terms of what you can make out of. Same thing applies as for PCB software though, don't use the same all time or you'll become a fanboy with rabies when you hear [insert your favourite micro's competitor's name here].Step 4. Upping the gear.So you should be starting to grow your old lab out, it should be time to upgrade it (still, only when you actually need it!).This step is entirely optional and depending on your situation (financial or morale).You should probably get a function generator, an LCR meter, and an ESR meter (The ESR meter you can build yourself). These things help you measure more things (obviously) and the function gen can clock signals or sample signals into your devices.you might need a digital storage oscilloscope for your stuff, maybe you do lots of amps and you need a high voltage power supply, or if you're into signal transmission stuff, you might need a spectrum analyzer, or a digital signal analyzer, a frequency counter, a reflow oven, whatever! Get what you need! Can't emphasize this enough.Step 5. The end?Short answer: no.Long answer: Technology evolves constantly. As you're reading this, science teams in Intel, Fairchild and other big companies constantly file patents for things they found out, and they won't stop any time soon.Think ofMoore's law: The amount of transistors on a silicon die of the same size doubles every two and a half years!There's new methods discovered, new materials used (transistors might be switched up for memristors in the upcoming decades. This will be the same thing as going from valves to transistors was back then), new test gear made, etc. You have to keep up, or you'll be stuck in the middle ages! Read those datasheets, check those application notes, do whatever you can to keep yourself up-to-date. Dave's videos are also a great way of doing this, as he shows lots of things from old to new that you can learn from.All in all, these are just guidelines, not a set in stone bible that you have to follow. I hope I helped you out with this little wall of text in making you a better electronics enthusiast.There's only one set in stone rule that you have to follow:Have fun while doing it!Edits:Fixed a few typos, Moore's law and added another tidbit about resistors

author: zapta
author_rank: Super Contributor
timestamp: June 20, 2014, 08:42:59 pm
content: Or, get an Arduino board and a shield and declare victory ;-)Seriously, what about a section about understanding basic components (resistors, capacitors, diodes, transistors, etc)? Also understanding how to read schematics and the relationship between a schematic and an actual circuit.

author: bwat
author_rank: Frequent Contributor
timestamp: June 20, 2014, 08:48:58 pm
content: Quote from: RazSlack on June 20, 2014, 08:19:44 pmYou don't need to know how a microprocessor works to be able to write good assembly. The assembly language programmer needs to understand theISA. He/she probably has no need to know how that ISA is implemented. For example, does the programmer need to know if the CPU has a hardwired ormicrocodedcontrol unit? If you compare these two simplistic 16-bit CPU designs, you see that they have very similar, if not identical, ISAs but are implemented very differently:microprogrammed example,hardwired example.Quote from: RazSlack on June 20, 2014, 08:19:44 pmAre you sure about that? Is it not the number of transistors doubles every two years?

author: zapta
author_rank: Super Contributor
timestamp: June 20, 2014, 09:12:13 pm
content: Quote from: bwat on June 20, 2014, 08:48:58 pmIt doubles every other year ;-)

author: RazSlack
author_rank: Contributor
timestamp: June 20, 2014, 09:50:40 pm
content: Quote from: zapta on June 20, 2014, 09:12:13 pmYeah, bit of a slip there. Actually it's 18 months according to wiki.Quote from: bwat on June 20, 2014, 08:48:58 pmSure enough, but by that I meant having a basic understanding of how a jumping operation is handled, what does a "bus" mean, things like that. I think it should be known, or at least a good thing to know.

author: retrolefty
author_rank: Super Contributor
timestamp: June 20, 2014, 11:11:25 pm
content: Quote from: bwat on June 20, 2014, 08:48:58 pmI thought the 'law' states it doubles every 18 months over time on average?Quote

author: bwat
author_rank: Frequent Contributor
timestamp: June 21, 2014, 09:58:21 am
content: Quote from: retrolefty on June 20, 2014, 11:11:25 pmYour quote is about chip performance when the OP and I are discussing transistor density.Anyway, it is still confusing. This morning I found this in Hennesy & Patterson,Computer Architecture, A Quntatative Approach.Morgan Kaufman, 1993.Quote

author: VEGETA
author_rank: Super Contributor
timestamp: November 14, 2014, 01:36:16 pm
content: thanks for your topic, it is good. However, I do not think that learning Assembly is needed today. Learning C and at the same time learning what interrupt and other MCU stuff works is good enough.

author: magetoo
author_rank: Frequent Contributor
timestamp: November 15, 2014, 09:15:47 am
content: Nice writeup, shame it will get buried in the forum along with all other topics. Maybe take suggestions for improvement and try to get it posted somewhere like Hackaday?Quote from: RazSlack on June 20, 2014, 09:50:40 pmI can't resist quoting the relevant page fromWiki:Quote from: WikiWikiWeb(Yes, just so I can point out Wiki vs. Wikipedia.)