Hitting the ground running - Page 1
Forum section: electronics / beginners

author: Phuzzy112
author_rank: Newbie
timestamp: March 25, 2019, 09:31:45 am
content: Hi All,Newbie here, of sorts. I have poked a fair few circuits with a meter probe over the years and voided my share of warranties in the process, but never got to actually setting up a proper workbench and actually doing things that don't start with an established datasheet. I can solder, I can follow a schematic and I can troubleshoot most simple circuits, but I have no idea what the forward drop of this thing here is or why I need to tie this ground to that thing there...Basically if a component has more than 2 pins, I would be lost.I am hoping to change that all though: I have just dropped a few hundred on a DS1054, a soldering station with temperature control, at least one new multimeter (this month at least), various power delivery apparatus and several shipments of chinesium to get me set up. Objective one will be to work my way through the NEETS, allaboutcircuits.com and the stickied video intro to the scope, then I hope to get started on building (and actually understanding) a LM317-based power supply for my bench. By the end of this year I will be able to actually design something from the ground up!My questions to the good folks here would be:I have a common problem with a lot of the commonly-recommended reading material online (including the ones above): I know how to apply Ohms Law, I know what a resistor color code is and how to read it. Yes I know what direction the pointy bit of the soldering iron goes....... Is there something like a "not completely newbie introduction"?(I am going to slog through the big books anyway, but a more intermediate guide to things usually helps my brain out a bit faster)What would you recommend as a good starter project set to learn as I go? The PSU is one I picked because I have used the 317 in a few simple applications before - mostly just reading the datasheet and picking a reference design that makes sense - but only know enough about it to do the basics, so figured it was a good starting point. It is also something I will have a practical use for on my bench, which I really like.Where the hell do you guys find the dumpster diving spots?!? I have never come across anything remotely useful anywhere near a dumpster...(edit: I just realized this should go into General. Doh! teach me to read more before posting)

author: jimmeh11
author_rank: Newbie
timestamp: March 25, 2019, 11:00:55 am
content: Hi mate, welcome to the electronics lifestyle.As far as your questions go:1. Electronics is a really broad topic which can range from highly technical and theoretical detailed design to fast turnaround just-make-it-work-so-i-can-move-onto-the-next-project designs. The learning approach that's best for you will depend how deep you want to get.For me, I've found that I learn best when I'm exposed to as many new things as possible at a high level, then when I find things that interest me I can dig deeper on my own. For this, I find Chris Gammell's (and sometimes Dave's) podcast 'The Amp Hour' is great, especially the interviews.If you're slightly more into the idea of starting with some general theory, The Art of Electronics (Horowitz & Hill) is a great, practical guide to electronics theory. There are also plenty of free options, but I'm not familiar with them.2. First project is really important, I think. A PSU is great, but make sure you keep on top of the feature list. Make it something useful and achievable, rather than listening to far more experienced people who are telling you to add complexity you might not need. FACT: 95.7% of electronics projects are NEVER completed.My first projects were an audio amplifier for my PC speakers (because I needed one) and an automated sprinkler controller (because I wanted one). Whatever it is you make, it won't be perfect but it'll feel great when it's done.3. Dave's dumpster is mythical, they don't exist. But honestly, companies, schools and universities (and old engineers) accumulate crap and if you're in the right place at the right time you can snag a bargain. For the rest of us, set up search alerts on Ebay and Gumtree and wait for a deal.James

author: DimitriP
author_rank: Super Contributor
timestamp: March 25, 2019, 12:33:02 pm
content: QuoteRead on topics that interest you, that you want to learn what makes them tick. Reading for the purpose of answering your own questions is more useful that starting with chapter 1 of any one book.

author: rstofer
author_rank: Super Contributor
timestamp: March 25, 2019, 02:46:46 pm
content: A lot of hobby electronics is copy and paste from somebody else's work. One step up is designing your own circuits and that takes a little more theory.Khan Academy has an Electrical Engineering track. Digilent has a RealAnalog program. Both of these are math centric because, well, engineering is math. There is a little bit of math needed for elementary circuit analysis.Ohm's Law is the place everybody starts and with good reason. Beyond that are Kirchhoff's Laws, Norton's Theorem, and Thevenin's Theorem. You need these for even the easiest circuit analysis. Mesh and nodal analysis are derived from these Laws and Theorems. If you ever plan to use an op amp, you will need Kirchoff's Current Law plus Ohm's Law.These are the primary topics of a first semester EE course and, once learned, you will be a long way down the path of electronics.

author: Jwillis
author_rank: Super Contributor
timestamp: March 25, 2019, 10:04:59 pm
content: Complex circuits are just simple circuits joined together.Simple circuits are made of various components that interact with each other to produce a desired result.Understanding how each component works is the best start.Then understanding how simple circuits work is the next step.Your LM317 regulator would be considered a complex circuit made up of a few simple circuits made of various components like transistors .resistors and diodes etc. of varying types etched on a chip enclosed in plastic and metal.Each component you use will have a Datasheet available to show what parameters that component is capable of .So understanding Datasheets of the various components you use will help enormously.Many datasheets will include a schematic of the chips circuit or at least a block diagram others won't because the complexity is so high it would take several volumes of diagram.There are various sites that can help with learning how components work and the interaction with other components.Some require more existing knowledge than others and others are more basic.http://hyperphysics.phy-astr.gsu.edu/hbase/index.htmlandhttps://www.electronics-tutorials.ws/are two I use a lot.Don't be intimidated by the math it will come. There are many online calculators that can help to explain how the math equations work.A basic understanding of algebra helps.Good luck and have fun.

author: 0culus
author_rank: Super Contributor
timestamp: March 25, 2019, 10:15:48 pm
content: Here's my 2 cents. It's proving entertaining for me, YMMV!My background is not in EE, but rather mathematics and computer science. So I've seen plenty of theory (clarity edit: in math and CS, not EE) and done lots of proofs. I certainly don't regret it! My research for my MS involves FPGAs, which has been a lot of fun. However, I've always had an interest in electronics and RF, so now that I've got a bit of money, I'm diving headlong into not only acquiring test equipment to build an awesome lab, but also diving into books to correct gaps in knowledge. I must admit, that after proof filled theoretical math and CS courses, working on stuff with a more engineering bent is a lot of fun. That said, as someone with a mathematics degree, Maxwell's Equations are interesting in and of themselves, so I *also* need to brush up on PDEs.I ended up getting the Art of Electronics 3rd edition and the lab manual (which does have mistakes and misprints in it!). Somewhere on this forum, an enterprising member put together a handy spreadsheet with all the component SKUs you need to purchase to build all the lab projects. I figure I might do this later this year. Right now, I'm just reading and building what I can. I also got Bowick's RF circuit design book.

author: rstofer
author_rank: Super Contributor
timestamp: March 26, 2019, 09:05:57 pm
content: Quote from: 0culus on March 25, 2019, 10:15:48 pmDigikey has the items all included in a kit:https://www.digikey.com/en/resources/edu/harvard-lab-kitOver the years, some parts have become obsolete. I don't know what Digikey has done to the kit. Maybe they substituted, maybe they omit.I'm glad you enjoy Maxwell's Equations. That course kicked my butt! I passed but I don't recall the details. Divergence and Curl in the days of slide rules (that is, decades before the Internet) was not enjoyable.

author: 0culus
author_rank: Super Contributor
timestamp: March 26, 2019, 09:58:43 pm
content: Quote from: rstofer on March 26, 2019, 09:05:57 pmOh that's handy. I suppose substitutions could be found manually if you know what's missing.Quote from: rstofer on March 26, 2019, 09:05:57 pmHaha, thanks. I'm one of those weird people who does math for fun.My personal favorite courses of my math degree were complex analysis and differential geometry. I'm looking forward to flexing those muscles again.As to doing all that with a slide rule, my hat is off to you, sir.

author: Phuzzy112
author_rank: Newbie
timestamp: March 27, 2019, 10:31:19 am
content: Thanks for the feedback everyone!Quote from: jimmeh11 on March 25, 2019, 11:00:55 amOh yea this will be a pretty simple one: +5V via the 317 reference circuit for using external transistors to supply a higher current. I know I could probably solder up the reference design pretty quick, but I want to actually step through the design of the circuit and understand why the components are used where they are.Quote from: 0culus on March 26, 2019, 09:58:43 pmOh, that looks like a winner! I think I will be placing an order for that book pretty soon. The components though... not sure. The full bundle costs more than some of the secondhand kit I have been eyeing so I will probably have to cherry-pick the designs I want to tinker with and order just those.Quote from: Jwillis on March 25, 2019, 10:04:59 pmThanks! I will add them to my bookmarks. I have a nice list going now

author: Old Printer
author_rank: Frequent Contributor
timestamp: March 27, 2019, 12:46:00 pm
content: More or less started where you did a few years ago. At 66 I went to the book store and bought an adult refresher on pre-algebra. I have watched a million YouTube vids which get me off into areas of interest I didn't even know existed. Then I find myself learning about logic chips after they are all but obsolete. I am still trying to really understand AC, capacitance, inductance etc. I have learned what makes vacuum tubes work, somewhat...talk about obsolete, except i am a guitar player with some nice old valve amps to work on. There is no end to it, wish I was a lot younger.

author: rstofer
author_rank: Super Contributor
timestamp: March 27, 2019, 04:13:32 pm
content: Quote from: 0culus on March 26, 2019, 09:58:43 pmHere's a project that will tie together math, op amps and general electronics. But it's the math that is fun.Breadboard up a couple of 1 second integrators (from op amps) using 1 ufd capacitor and 1M Ohm resistor. You need two. Then breadboard up a couple of summer/inverters and use some kind of toggle switch to set the initial conditions of an analog computer simulating damped harmonic motion.Hint: Lord Kelvin's method works well. He was an absolute genius re: analog computing based on his brother's mechanical integrator. Isolate the highest derivative on the left and divide out the coefficient. Then, assuming you actually have the second derivative, use integrators, summers and potentiometers to build the right hand side. Then we have the MAGIC of the '=' sign: Take what was created on the right hand side and route it back to the first integrator as y'' because the '=' sign shows we just created y''. Absolute genius!See attached PDF of MATLAB Simulink implementation of Damped Harmonic Motion.Since the op amps are inverting, that -1 inverter comes free with the summer ahead of it. The damping and spring constants are just potentiometers.The point of the exercise is to use op amps as they were intended: Operational Amplifiers. Analog computing and, of course, the solution of certain types of differential equations. And modeling the rocket nozzle controls of the Atlas missile. That was kind of important... We can't have the thing falling down! Car suspensions use a similar equation - probably dolled up to consider physical limits and so on.See Vernier Rocket:https://www.grc.nasa.gov/www/k-12/rocket/rktcontrl.htmlI had nothing to do with the Atlas control system but my Control Systems instructor did!You can see my first analog computer here:http://www.analogmuseum.org/library/vogel_schaltplan.pdfhttp://www.analogmuseum.org/library/vogel_ar_beschreibung.pdf(German but easy to translate from context)BTW: The Vogel Analog Computer has enough resources to work the Predator-Prey problem.That ought to keep you busy!

author: rstofer
author_rank: Super Contributor
timestamp: March 27, 2019, 04:29:59 pm
content: Quote from: Phuzzy112 on March 27, 2019, 10:31:19 amI would look a couple of labs ahead and order what I needed. I might pay extra in shipping but DigiKey offers Priority Mail and it's only about $7 and it's FAST!As to learning AC (mentioned above), you can learn a lot with a simple variable frequency sine wave generator, a resistor and capacitor. Maybe pick the values for a 100 Hz low pass filter (calculators all over the Internet). Use at least a 1k resistor to protect the generator. Remember: At high frequencies, that capacitor will look like a short circuit. The resistor protects the generator.Now, hook up the low pass filter and measure the voltage across the capacitor as you measure frequency (how?). Plot the results with Excel (or anything else) and you have some idea of the impedance of the circuit versus frequency.Now reorganize the circuit into a high pass filter and measure the voltage across the resistor. Overlay the first plot.Now cascade the low pass and high pass filter (second schematic here)https://www.electronics-tutorials.ws/filter/filter_4.htmlIn the end, you will understand where the breakpoint is and if you can plot the frequency on a log scale, you will have a real Bode' plot.Everything in AC is based on impedance which is usually a function of frequency.There's a lot to learn from a couple of resistors and capacitors.