I'm spoiled by Arduino and I want to learn the things I missed out on - Page 1
Forum section: electronics / beginners

author: iamericmin
author_rank: Contributor
timestamp: August 28, 2019, 01:44:24 am
content: Hi everyone, this is my first post here. Sorry if my post sounds confusing, english is not my first language.I am a teenager with a deep passion for electronics and computer science. As my hobby, I design, manufacture, and assemble PCBs. For example, this is my biggest project so far, a BLE-capable wristwatch based around an nRF52 SoC:https://iamericmin.github.io/tm4.htmlOf course, I also tinker around with normal perfboards, breadboards, and messy wire-wrapped hand soldered circuits. I teach myself everything so this is where my problem arises.While I am very proud of myself of the things I've done so far, I can't help but think I've been "spoiled" by Arduino and the likes. I want to learn how a 555 timer works. I want to know what the heck an op-amp is. I want to know how to build my own 8-bit computer. What the heck is a rectifier and where do I use one? I never had the need to use any of these because my projects only required a single microcontroller and some passive components. Why would I use a 555 timer when my uC can send precisely timed pulses? Why make a voltage divider when my uC has PWM? While I am somewhat comfy with microcontrollers, I have no idea about any of the nitty-gritty stuff. I merely followed instructions without learning the how and why.I recently realized this issue and looked up the hundreds of tutorials and lectures on youtube. Almost none of them made sense to me. I read online tutorials, beginners' guides, you name it. I now think I'm left with this giant "knowledge hole" of stuff I'm supposed to know by now. I am sort of lost in my passion and would love some guidance into how I can get into serious EE without having to rely on things like the Arduino ecosystem. Don't get me wrong, It's a wonderful tool that brought me to where I am now, but I feel I'm at the stage where I should stop using it.Again, sorry if this sounded confusing or unnecessarily long. I just want some guidance from y'all experts. Thanks!

author: Psi
author_rank: Super Contributor
timestamp: August 28, 2019, 01:50:53 am
content: Afrotechmods has a selection of videos about how various parts work and he explains them well.https://www.youtube.com/user/Afrotechmods/videos

author: rstofer
author_rank: Super Contributor
timestamp: August 28, 2019, 01:59:35 am
content: Pick a single topic and work on it. If you want to pick them all, concurrently, all I can say is Good Luck!Dave made a video or two on op amps as did w2aew.There are other videos on YouTube but I know these two are excellent. Once you have the basics down, there are thousands of projects on the Internet."Op Amps For Everyone" is a free download and an excellent reference.555 timer projects are all over the place. There is a little over 3 MILLION hits on Google for '555 timer project'.Of course, you should download the datasheets for everything you use and try to figure out what all the numbers mean. Every single number in the datasheet puts a limit on what you can do with it. Every single number is important at some point in the design process. Even if just to know that a limit exists. You can always ask specific questions about values in the datasheet.Google for 'Ben Eater 8 bit' and you will turn up some information on a discrete logic implementation of an 8 bit computer. Videos and all!I suppose "The Art of Electronics" and the lab manual "Learning the Art of Electronics" ought to be on the list.

author: rstofer
author_rank: Super Contributor
timestamp: August 28, 2019, 02:07:41 am
content: If you actually want to learn electronics, realize that it is an intense application of math. At a minimum, you need Ohm's Law, Kirchhoff's Laws, Norton's Theorem and Thevenin's Theorem. DigilentInc.com has a "Real Analog" program that tries to teach entry level electonics. Khan Academy has an EE curriculum as well as their math programs.Those 4 theorems and laws will keep you going for a while. That's good because the next step takes more serious math. Step response and AC circuits are all about math. There's plenty to learn! Khan Academy can help for all of it.

author: iamericmin
author_rank: Contributor
timestamp: August 28, 2019, 02:07:57 am
content: Thanks rstofer, but one thing: I've tried almost all, if not all, of the stuff you suggested.Am I just not trying hard enough? Or am I too stupid to understand? For example, EEVblog's Fundamentals Friday on Op-amps was so hard to understand for me that I just quit before the 10-minute mark, all 5 times I've seen and tried to understand it. There were just too many words I didn't know.EDIT: I know that EE is essentially fancy hard math, but the best I've done is Calculus AB. All the equations I see have complex symbols and big constants that I don't yet know how to handle.

author: vk6zgo
author_rank: Super Contributor
timestamp: August 28, 2019, 02:49:24 am
content: Quote from: iamericmin on August 28, 2019, 02:07:57 amThe major problem these days is that there is no wide ranging introduction to the various concepts involved in (particularly) analog Electronics.This website is interesting, in that it covers a lot of stuff in an interesting manner.I'm not suggesting that it will "teach you Electronics" but it may kindle an interest in stuff beyond Arduinos. Maths used are not hard, & there are a lot of graphs & so on.http://users.tpg.com.au/users/ldbutler/Have you had a look at some of W2AEW's Youtube videos?Alan talks to you like you are a visitor to his "Ham Shack", & most of his Maths are easy, too.Obviously, if you want to go to University & do a Degree, you will need to use higher Maths, but to just get a "feel" for things, your existing knowledge will be more than adequate.After all, If you want to learn to swim, you don't make your first venture crosing the English Channel

author: themadhippy
author_rank: Super Contributor
timestamp: August 28, 2019, 03:01:24 am
content: Forget the maths and fancy words ,get in there andplayexperiment,buy a few 555's , op amps etc and build a few simple circuits on breadboard,change components about and see what happens,blow things up,let the magic smoke out,slowly things will slip into place and the fancy words and maths will begin to make sense.

author: mindcrime
author_rank: Unknown
timestamp: August 28, 2019, 03:07:09 am
content: If you want to be a professional Electrical Engineer, you will definitely need some maths knowledge. If you want to be a good / above-average hobbyist, you probably need some maths knowledge. If you want to tinker around, build occasionally useful and cool stuff, and can accept not always knowing every little detail of what's going on, you can get quite far as a hobbyist without lots of math. Of course you need to know basic arithmetic and probably high-school level algebra pretty much no matter what. If you look up an equation in a book or on a website, you want to know how to substitute in values and evaluate equations and what-not. And if your interests go in certain directions (various aspects of signal processing for example) then trig would come into play.But as a hobbyist who can build a fair amount of neat things, do you absolutely need calculus, linear algebra, or even higher level math (abstract algebra, real analysis, etc.)? In my experience, no. My maths education only took me through calculus and I manage to get some stuff done.My point though, isn't to suggest you avoid math. In fact, I'd go just the opposite.... I wish I *had* studied more higher level maths when I was younger. I'm trying to play catch up now, doing online classes and watching Youtube videos, and reading books on everything from Calculus to Linear Algebra to Fourier Analysis, Statistics, Probability Theory etc. No, my point is more to say something like "don't be intimidated by the math, and learn it as you go, as you need it." That is, unless, as somebody above said, you plan to go to university and get an EE degree, in which case higher level math will be part of the program.As to the rest... There are so many books, videos, websites, classes, etc. out there that it's hard to say where to begin. Just sample widely and when you find something that resonates (no pun intended) with you, grab that thread and follow it. And just to throw one specific recommendation out there:https://www.youtube.com/playlist?list=PL9F74AFA03AA06A11

author: rstofer
author_rank: Super Contributor
timestamp: August 28, 2019, 04:35:13 am
content: Quote from: iamericmin on August 28, 2019, 02:07:57 amI can’t recommend a specific op amp, maybe use what is in the videos. Duplicate the experiments as the video plays. I learn best by doing, not watchingYou do need Kirchhoff’s Law particularly the current law. Google for it.Prove that the + and - inputs are equal. Look up a summer, figure out why it works. My favorite circuit is the integrator. I like analog computing.Calculus is a real good start. It will carry you a long way.Got a scope? A good DMM? Sooner than later you will need a scope.. It helps to see what is going on.

author: rstofer
author_rank: Super Contributor
timestamp: August 28, 2019, 05:17:17 am
content: If you don’t have a +-12V power supply, build one from 7812 and 7912 regulators. Then you can experiment with LM358 op amp. Google for supply.

author: Old Printer
author_rank: Frequent Contributor
timestamp: August 28, 2019, 02:02:51 pm
content: At your point the two tools that will serve you best are patience and persistence. Pretty much everything you need to know is available to you online. Learning how to find it will take some practice. I am in my mid 60's and concentrate most of my effort on organizing resources rather than memorizing laws and formulas. As said above you need to thoroughly understand the basic laws like Ohm & Kirchhoff, but a lot of it will just take time and repetition to sink in. I have found the whole process to be more gradual and less ah ha moments. Put in your time, study as much as you can, build every basic circuit you can, and come here and ask "pointed" questions and it will all come to you.

author: eugenenine
author_rank: Frequent Contributor
timestamp: August 28, 2019, 03:25:13 pm
content: Search for "art of electronics" on this forum, it seems a lot of people recommend it. It starts with the basics and works up from there.Interesting your using the nRF SOC, have you tried messing with any of the ANT+ functionality?

author: reboots
author_rank: Regular Contributor
timestamp: August 28, 2019, 04:29:26 pm
content: Quote from: iamericmin on August 28, 2019, 01:44:24 amThese are great questions.#1: You wouldn't! The 555 timer is early 1970s technology. A small microcontroller is literally cheaper, and better in every way for many applications. However, there are special cases where the older part is still useful. For example, the 555 has a much higher voltage range than typical uCs. A 555 might be a good solution for a simple 12V timing application where a uC would need external driver circuitry, adding cost and complexity.#2: PWM might indeed substitute for a voltage divider. But you'll need a little bit of discrete circuitry to turn the PWM signal into a stable-ish voltage, so there is no advantage in terms of parts count. And there are drawbacks: consider that a uC will not generate PWM immediately at power on; there will be a very small lag before the PWM circuitry is initialized and enabled in firmware. If your circuit needs a known reference voltage immediately, a voltage divider would be a better choice.PWM would be more useful for cases where you want to be able to vary the voltage programmatically. Voltage dividers are cheap, simple, and basically foolproof.

author: rstofer
author_rank: Super Contributor
timestamp: August 28, 2019, 05:10:57 pm
content: I can plunk a 555 down on a breadboard, connect up a couple of resistors and capacitors and have the output before you can boot a PC to start writing code. Go easy on old-school technology. There's a reason it is still around.Try frequency modulating a fairly fast output on a uC. Then look at the simplicity of the 555 circuit:https://www.petervis.com/Radios/fm-modulator-using-555-timer-ic/fm-modulator-using-555-timer-ic.htmlIn the divider case, you will find when you play with op amps that you sometimes need a precise VCC/2 supply. The noisy output of the uC is NOT going to be satisfactory. In fact, the application is so important that they invented a 'rail splitter' chip. Imagine that! A chip dedicated to dividing a voltage in half (and providing a buffered output).http://www.ti.com/product/TLE2426Designers actually use these things!Arduinos are magic! In their domain, they rule! But their domain is a fairly small corner of the electronics sandbox. It's a pretty big sandbox and there is room for everybody.

author: rstofer
author_rank: Super Contributor
timestamp: August 28, 2019, 05:15:51 pm
content: "Getting Started In Electronics" by Forrest Mims is a pretty good book.https://www.amazon.com/Getting-Started-Electronics-Forrest-Mims/dp/0945053282Amazon isn't the cheapest provider, search around.Side issue: I buy a lot of used books from Alibris.com

author: fourfathom
author_rank: Super Contributor
timestamp: August 28, 2019, 05:44:57 pm
content: Others have already said this, but EE is *mostly* easy math. There are areas where the hard math is required, but when starting out it's generally pretty simple.Understand voltage, current, and Watts. Learn Ohm's Law and the permutations of E, I, R, and while you're at it P. Kirchoff's and Norton's Laws are pretty obvious -- don't be intimidated. Figure out how to make a voltage divider, and then see how it works with source and load resistance. This is all DC stuff, and you *need* to understand these fundamentals. This should take you a day or two (or an hour or a week, depending on your experience.) Algebra is the only math needed, and plain arithmetic is usually sufficient.Learning about AC vs DC is important, so look at RMS, peak, average relationships.Then look at capacitors and inductors. You can use the fancy math if you like, but I would rather see you get familiar with how they behave at a more "hands-on" level. Look at graphs of charging and discharging, R-C time constants, simple R-C low-pass and high-pass filters, etc. They are all related, and understanding the time-domain and frequency-domain behavior is important and extremely useful. You don't need hard math to get a practical feeling for this, or to be able to do simple (but useful) designs. Use a circuit simulator like LTSpice to see what happens in simple circuits.By this time, now that you are comfortable with the fundamentals you should be ready to look at diodes, transistors, op-amps, and other active devices. You can get into the hard math as you decide you need it. Don't worry about it now.

author: rstofer
author_rank: Super Contributor
timestamp: August 28, 2019, 06:04:40 pm
content: In the first 5 minutes of the w2aew video linked above, he covers the fundamental ideas of op amps. A couple of preliminaries: He is using the LM358 op amp - you should have a dozen or so on hand. He is operating it from a single supply of +10V. That is why he has the 'rail splitter' resistors (2.2k as he points out) providing a reference voltage (virtual ground) of +5V. That +5V goes to the + input of the op amp.Due to op amp action, the voltage on the - input will also be 5V. Assuming an ideal op amp, as he is, that - pin will ALWAYS be +5V. From there is is easy to see why, with 4V applied to the input resistor, there will be 1V drop across the resistor. Ohm's Law gives us 1V / 10k = 100 uA of current flowing away from the - input. But, from the rules, that current is NOT coming out of the op amp pin. No, the current comes through the 20k feedback resistor. That same 100 uA times 20k (Ohm's Law again) provides 2V drop so the output voltage is 2V above the 5V reference or 7V.They really are as simple as that! No current in or out of either input and no voltage difference between the inputs as long as negative feedback is applied. Technically, we played with Kirchhoff's Current Law at the - input but didn't call it that. The current into the node from the 20k resistor is equal to the current out of the node through the 10k resistor. The node is the - input pin. No current spills out on the floor and no current comes out of the pin.Get a breadboard and some source of 10V (or a 9V battery, change the arithmetic, the + input is now 4.5V) and follow along. I'll bet within a couple of viewings and matching experiments, you will understand op amps and the majority of circuits you encounter.I prefer NOT to have to use a rail splitter. I want a real ground just because it makes the math easier. The + input actually IS 0V, not some virtual value. For this you need dual supplies if you don't already have a PS. +- 15V is fairly common and right on the edge of what the LM358 can handle. I bought a dual 15V supply from Jameco.com. You would probably need to find it from a different supplier. Or build one. Earlier I mentioned 7812 and 7912 regulators, 7815 and 7915 will give you the maximum supply of +-15V. Ordinarily, you would design for a +- 10V signal swing. This leaves a little headroom between the signals and the supply rails.There are modern 3V single rail op amps around but many of the projects you will find on the Internet will be using the old uA741 with dual supplies. You can substitute the LM358 and save some money. Those old 741s are like gold!You really do need to breadboard the circuit and follow along with the video. It won't take long before you have it mastered.

author: rstofer
author_rank: Super Contributor
timestamp: August 28, 2019, 06:14:48 pm
content: Quote from: fourfathom on August 28, 2019, 05:44:57 pmUse an Arduino or 555 timer to generate a square wave and use it to charge and discharge an RC circuit. Watch the exponential charge and discharge on a scope. Set the square wave time to be about 6 times the time-constant of the RC circuit. 10k 100nf = 1 ms time constant. Set the square wave so each half is 6 ms (so total 12 ms) and figure the frequency as around 83 Hz. Pick a number <= 83 Hz.If the OP is test equipment challenged and the goal is to learn electronics, the Digilent Analog Discovery 2 is the way to get started. I'm not going to enumerate the features but suffice it to say that a LOT of electronics can be done with no other equipment. A DMM or two might be an advantage. A couple of AN8008 would suffice as long as they weren't to be used on mains.I particularly like demonstrating the RC charge/discharge example using the AD2. There's nothing like a 27" screen to bring the circuit to life!And, yes, I know the AD2 is pricey. But it's a heck of a lot cheaper than the equipment it would take to duplicate the functionality.