Voltage-divider circuit board application - Page 1
Forum section: electronics / beginners

author: the offset voltage
author_rank: Regular Contributor
timestamp: August 17, 2025, 01:29:25 pm
content: Hi,Following the book of Thomas L Floyd: Principles of Electric Circuits (self-study), i just finished Series Circuits section.Now, for this section i have this practical application circuit from Fig1.My question is, should i design it?, will this circuit be useful to me in future time?Thank you,Adrian

author: ledtester
author_rank: Super Contributor
timestamp: August 17, 2025, 01:40:18 pm
content: Quote from: the offset voltage on August 17, 2025, 01:29:25 pmNo , it will not be valuable in the future.

author: the offset voltage
author_rank: Regular Contributor
timestamp: August 17, 2025, 01:46:40 pm
content: Its a good project only with the objective of getting better in PCB design, even if that means to buy the components and pay the pcb manufacturer with the only objective to learn pcb design? or should i just skip this unpractical projects until i reach practical projects?

author: Grandchuck
author_rank: Super Contributor
timestamp: August 17, 2025, 01:51:27 pm
content: Just skip it.

author: the offset voltage
author_rank: Regular Contributor
timestamp: August 17, 2025, 01:57:36 pm
content: Thank you

author: tggzzz
author_rank: Super Contributor
timestamp: August 17, 2025, 02:39:45 pm
content: This is one of those things where you understand the principles, think about where it might be useful, and only build it if and when you know how it will be useful. For that example consider thinking about why R1 should/shouldn't be 1ohm, 1kohm, 1Mohm. Background: typical handheld DMMs have a 10Mohm input resistance, bench DMMs can have a 100Gohm input resistance, and analogue meters require 50uA to deflect from he needle to full scale.In general, don't buy/make something because it might be useful. When you know of a specific use, work out the precise attributes it must have, and then buy/make it.The alternative leads to completely filling your house with stuff that "might come in useful". I refuse to discuss how I know that and it's relationship to the mega TEA thread

author: the offset voltage
author_rank: Regular Contributor
timestamp: August 17, 2025, 02:46:24 pm
content: Pffff, if i have to evaluate all the projects like this, i can come with the conclusion that i will not need to design many projects from this book.Than how i manage to learn to design PCBs, if i will skip designing the project/s?Thank you,

author: Grandchuck
author_rank: Super Contributor
timestamp: August 17, 2025, 02:53:50 pm
content: Have you done any searching? For example:https://www.build-electronic-circuits.com/pcb-design/Next, anything you would like to have? power supply, signal generator, radio receiver, audio amplifier ...Finally, studying actual circuit boards can be helpful ... especially when you have the schematics that go with them.Good luck learning

author: the offset voltage
author_rank: Regular Contributor
timestamp: August 17, 2025, 04:17:04 pm
content: I have already designed two pcbs, i am getting familiar with the process from a course and designing the projects from Floyd book so far.In my case, should i replace the unpractical projects from Floyd book with more practical project from Elektor magazine for example?

author: tggzzz
author_rank: Super Contributor
timestamp: August 17, 2025, 04:35:29 pm
content: Quote from: the offset voltage on August 17, 2025, 02:46:24 pmThere's no single way to do it, of course. I like your combination of theory and practice; that will be valuable to you in the future.Maybe you will think of something that you want to design and build?The trick is to find something that is new and difficult for you, but can be done within a reasonable time.A good way of doing that is to read examples of what other people slightly more experienced have done, understand how they are supposed to work, and then design and build something similar.When I was young the only way of doing that was to read hobbyist magazines found in local newspaper shops. In the 1930s you had to get books; I have one such book, The Boy Electrician, which gives hints for building and playing with your own X-ray machine (if your skin becomes red, you are using it too much!). Nowadays perhaps adapting the output of, say, an Arduino to do something or other.I'm not the best person to ask about modern equivalents, but perhapshttps://www.instructables.com/https://makezine.com/https://www.elektormagazine.com/or some of the 1970s/80s/90s magazines at (earlier than that and there will be a lot of valves, later and there will be too many computers)https://www.worldradiohistory.com/Maplin-Electronics.htmhttps://www.worldradiohistory.com/Wireless_World_Magazine.htmhttps://www.worldradiohistory.com/ETI_Magazine.htm

author: the offset voltage
author_rank: Regular Contributor
timestamp: August 17, 2025, 05:16:25 pm
content: I see like this:1. i can continue learning the theory and designing the unpractical but cheaper pcbs for floyd book. And i will understand much better as the projects are linked with the theory;2. I can continue learning of course from the book of floyd and in parallel design from Elektor magazine. But, the components for elektor projects will be more expensive and i will have difficulty in understanding the elektor projects compared with floyd book.What should i do? i am lost now

author: tggzzz
author_rank: Super Contributor
timestamp: August 17, 2025, 05:32:21 pm
content: Quote from: the offset voltage on August 17, 2025, 05:16:25 pmTake it slowly. Do whatever feels right for you. Find your own path, at your own pace.Don't taketoomuch notice ofsuggestions, especially if doesn't feel right or fun.

author: the offset voltage
author_rank: Regular Contributor
timestamp: August 17, 2025, 05:36:44 pm
content: 🥺

author: BeBuLamar
author_rank: Super Contributor
timestamp: August 17, 2025, 06:56:01 pm
content: It's best if you treat it as an excerise in determining the values of the resistors using the color code as well as calculating the voltages of the divider. That's all. There is no value in designing the PCB and if you want to check your calculatiions against resistors with tolerances then just get a the resistors solder them in series connect them to an accurate 12V source and measure. I wouldn't bother to build the PCB. As I said with all your project you really obessed with PCB design.

author: the offset voltage
author_rank: Regular Contributor
timestamp: August 17, 2025, 07:26:22 pm
content: Well

author: the offset voltage
author_rank: Regular Contributor
timestamp: August 17, 2025, 07:27:35 pm
content: The author wants a link between theory and pcb design, so i just follow the book. If you think that the author is not knowledgeable its not my fault

author: tggzzz
author_rank: Super Contributor
timestamp: August 17, 2025, 07:48:19 pm
content: Quote from: tggzzz on August 17, 2025, 05:32:21 pmQuote from: the offset voltage on August 17, 2025, 05:36:44 pmDifferences between when I started and when you are starting....When I started you got information from monthly magazines (which you could afford). Alternatively from library books, which might take several weeks to arrive. Alternatively from second-hand partially obsolete books you happened to find. Information was scarce.Consequence: the key skill was to carefully read and re-read any and every source to glean as much information you could extract.Now there is an uncounted number of websites, forums, blogs, data books, application notes, textbooks available instantly without you having to stand up.Consequence: the key skill is to quickly and speedily decide which sources to ignore - the exact opposite.Information is still scarce, but now it is swamped by are data.Which is better and why? Discuss.My opinion: you are lucky to have so much available, but without skill and experience you will waste time on stuff that isn't worth your time. Especially 99.9% of yoootoob videos. even The Art of Electronics, uploaded by one of the authors, Win Hill. It is still available where he put it, and I imagine it has been copied elsewhere.

author: Analog Kid
author_rank: Super Contributor
timestamp: August 17, 2025, 07:48:41 pm
content: I agree:Learn how to design voltage dividers, how they work, how to select resistor values: very important!For this "project", just skip making a PCB; it's trivial, and the project isn't useful in a general-purpose way

author: xvr
author_rank: Frequent Contributor
timestamp: August 17, 2025, 07:51:09 pm
content: QuoteThis project is definitely not for PCB design but for learning about voltage divider circuits.The PCB here is trivial, there is nothing to learn in terms of PCB design.

author: tggzzz
author_rank: Super Contributor
timestamp: August 17, 2025, 07:59:09 pm
content: Quote from: xvr on August 17, 2025, 07:51:09 pmI disagree. For a first PCB designeverythingwill be learning.

author: Analog Kid
author_rank: Super Contributor
timestamp: August 17, 2025, 08:02:03 pm
content: Quote from: tggzzz on August 17, 2025, 07:59:09 pmYes, but hasn't the OP already got a PCB design going elsewhere here?This one just seems too trivial, thus a waste of time.Pick something worthwhile for your next PCB.

author: the offset voltage
author_rank: Regular Contributor
timestamp: August 18, 2025, 03:41:52 am
content: I will do like this: i will replace Floyd application with Elektor projects, i will do one project a month from Elektor because i like to design PCBs, as Elektor projects are practical and real life i should not have any complains. It will be funny as in the morning i will learning about capacitors and in the afternoon i will design a pcb maybe for a circuit that have an IC 😂

author: stoica adrian
author_rank: Contributor
timestamp: August 18, 2025, 05:50:56 am
content: It's better like this. Focus now on analog and integrated circuit (IC) projects from Elektor. Include microcontrollers and FPGAs when you learn about digital electronics + C programming.Focus on Floyd book for theory learning, (also see that Floyd has Electronic Devices and Digital Fundamentals books, beside the one you are using), do not skip the problems and use LTspice simulation to check your answer.Focus on Elektor only for PCB design skills for now.

author: the offset voltage
author_rank: Regular Contributor
timestamp: August 18, 2025, 06:37:38 am
content: OKRegarding the PCBs, I will skip the PCB applications from Floyd, and i will design PCBs from Elektor magazine.For the theory, yes, i will try to solve all the problems from Floyd, and i will also try to simulate them on LTspice.I also check the other books of Floyd.Thank you

author: BeBuLamar
author_rank: Super Contributor
timestamp: August 18, 2025, 08:06:18 pm
content: I didn't see that they tell you to make the PCB or actually build the circuit. You only need to write. You need to do1. Using color code determine the values of all the resistors.2. Do the calculations to determine the "Expected Voltages". Compared with the "Measured Voltages" they provided.3. Explain the possible reason for why the measured voltages are not matched the expected voltages like resistors tolerances etc...4. Calculate the current draw and determine if the 1/4 W is sufficient.5. Calculate how long the 6.5Ah battery will last with the current draw you calculated.

author: tggzzz
author_rank: Super Contributor
timestamp: August 18, 2025, 09:18:12 pm
content: Quote from: BeBuLamar on August 18, 2025, 08:06:18 pmCorrect.He has chosen to domorethan specified in the textbook. If nothing else, that looks good to employers during interviews.He has chosen to check the theory matches the world i.e. ascientificexperiment. Repeating past experiments is not done frequently enough; there is an on-going scandal with the number of published results that cannot be duplicated.He has chosen a way to add practical experience to his theoretical understanding. Each supports the other, both arenecessary, neither aresufficient.He is having fun.Really, given all that, what's not to like?Would you or I do exactly what he has done? No. So what.

author: BeBuLamar
author_rank: Super Contributor
timestamp: August 18, 2025, 10:04:10 pm
content: Quote from: tggzzz on August 18, 2025, 09:18:12 pmWasting time. Should go on with theory. For like a couple of weeks now there isn't much in term of electrical theory. But any way he does what he wants. Just an opinion.

author: tggzzz
author_rank: Super Contributor
timestamp: August 18, 2025, 10:08:39 pm
content: Quote from: BeBuLamar on August 18, 2025, 10:04:10 pmYou and I would be wasting our time.It seems I have to point out that the OP is before the start of his career. He is in a different position, so the assessment will be different.