hybridfree/eevblog-posts huggingface dataset:
PCB Review Request - Power Distribution Board for a Drone - Page 1
Forum section: electronics / projects

author: mila_dae23
author_rank: Newbie
timestamp: February 07, 2024, 11:33:09 pm
content: Hi everyone! I am part of an team designing autonomous drones. Although not expert circuit designers, we intend to make our custom power distribution board for a micro drone. I made the design in KiCad and would love to hear your thoughts on it!The board is supposed to supply :20A at 17.4V to a 4in1 ESC (powering 4 BLDC motors) max.5.3V to flight controller at 2.5A max.12V to video transmission system at 1A max.Before buying the components, requesting a review of the work.PDBV2-D002SCH.pdf(898.8 kB - downloaded 122 times.)PDBV2-D002BRD.pdf(93.84 kB - downloaded 113 times.)Image:3D VIEWTOP LEVEL AND BULK CAPACITORBUCK CONVERTERSFRONT CUINNER CU 2INNER CU 1 AND BACK CU ARE GND POURSFor the prototype and testing stage I plan to run it at low currents and use 1oz copper on all four layers as it’s cheaper.Some of the things that I am eager to have reviews on:Buck converter layouts on front cu.Current sensor layout on front cu.Effectiveness of the 330uF electrolytic capacitor against hot plugging and motor disturbances.The layup goes:Front Cu : Sensors and Buck Converters, Battery and GroundInner Cu 1: GroundInner Cu 2: Sensors and Buck feedback, Battery and GroundBack Cu: GroundThank you!
updated with better files for PCB REVISON: smart pixel differential receiver. - Page 1
Forum section: electronics / projects

author: Pr0cess0r
author_rank: Newbie
timestamp: February 23, 2021, 05:35:32 pm
content: Since i dont have any reply yet i completly edited this post.Im designing a board and would like you help to make my pcb design better.What it do: Its a board that receive 4 differential data line and convert them back to spi signal for ws281X adressable LED. It also power those sting up to 5A.Ok here are all the files so you can see my design.PDF files of front and back:https://docdro.id/J0KBj72https://docdro.id/dvV2SQ8New 3D render:SVG files of the 2D render:https://svgshare.com/i/UNn.svghttps://svgshare.com/i/UQr.svgshematics in PDF format:https://docdro.id/p8mNK29Hope those files will be easy to look at !Thank you for all your help it allow me to learn a lot!
PCB routing question - Page 1
Forum section: electronics / projects

author: halexa
author_rank: Regular Contributor
timestamp: November 19, 2014, 08:03:51 am
content: Hi,Is it bad practice to route tracks to the side of an IC pin?As shown in the picture:

author: Precipice
author_rank: Frequent Contributor
timestamp: November 19, 2014, 08:15:22 am
content: It's fine. More concerning on that board - are you planning to use the pale blue as silkscreen? If so, it's awfully close to the pads.What isn't fine is running from the side of one pad into the side of its neighbour. When you're inspecting, this can look like a solder bridge, and you'll waste time trying to 'fix' it. This is especially the case on fine pitch devices, where there's no solder mask between pins - then there really is a solder bridge, and it'll worry you every time you look at it.

author: halexa
author_rank: Regular Contributor
timestamp: November 19, 2014, 08:43:48 am
content: @"Precipice"Thx for the tips.Regarding the silk screen I used KiCads stock footprints, but maybe they need some tweaking cause my plan is to use the blue as silkscreen.
PCB, Routing SPI Bus pitfalls - Page 1
Forum section: electronics / projects

author: gogoman
author_rank: Regular Contributor
timestamp: November 26, 2016, 04:47:26 pm
content: Hi trying to eliminate mistakes before a fab,The bus consist of one sources and two destination. The routing is "T" Shape. The bottom of the "T" connects to the source. The top of the "T" connects destination A and destination B. The length between destination "A" to "B" is 12 inches and the source branch ~5 inches. The Bus Speed is ~3mhz.At the source end 50 ohm resistors are in series with the CLK and MOSI, At the destination A/B end, a 50 resistor is in series with the MISO line.Is this the proper method the terminate the line, is there a better method?Trace length, how closely match should they be?Is there a recommend trace width and spacing?thanks

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: November 26, 2016, 04:59:53 pm
content: At 3MHz, pretty much anything will work -you'd have to get prety creative to come up with something that wouldn't.Series R's can't hurt, and should deal wirh any issues caused by fast risetimes.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 26, 2016, 06:32:35 pm
content: Er, well... the MHz doesn't matter, the edge rate does.I'm happy with the described design. You could even use much larger resistors (up to maybe 220 ohms), which will slow the edge and reduce EMI (if that's a concern).I'm assuming the traces go over ground plane.Tim

author: gogoman
author_rank: Regular Contributor
timestamp: November 26, 2016, 07:05:55 pm
content: Quote from: T3sl4co1l on November 26, 2016, 06:32:35 pmyes, Routed over continuous planeregarding length any thoughts?thanks

author: gogoman
author_rank: Regular Contributor
timestamp: November 26, 2016, 10:21:31 pm
content: Quote from: blueskull on November 26, 2016, 07:25:41 pmEEweb reports an impedance of 57 ohms, 10 mil micro strip and 7mill height (distance between inner layer 2 and micro strip ).with a 6 mill micro strip 10 mill height the reported impedance is 73 ohms.with a 6 mill micro strip 4 mil height the reported impedance is 54.9unsure why the difference

author: void_error
author_rank: Frequent Contributor
timestamp: November 29, 2016, 07:15:05 am
content: Instead of starting a new thread I thought I'd post here...If I understood correctly each of the devices on the SPI bus needs a series resistor close its output pin?If my micro has output current control could I use that to limit rise/fall times?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 29, 2016, 12:38:09 pm
content: Yes. Output current, or drive strength, or slew rate limiting, are suitable alternatives.Tim
Critique request  — 18650 battery pack protection PCB / schematic - Page 1
Forum section: electronics / projects

author: microbug
author_rank: Frequent Contributor
timestamp: July 28, 2015, 07:44:22 pm
content: My current project is a protection circuit for 4 lithium-ion 18650 batteries, which effectively turns them into a 4-cell (series) battery pack with protection. The protection is provided by 4 TI BQ29703 single-cell protection chips (one per cell). These provide all the (primary) protection needed (the project I'll use this with will have a low-voltage cutoff and a fuse for added safety).The PCB / schematic files can be foundhere. They are in KiCad (I have generated PCB gerbers in case you don't have it). I have also attached a PDF plot of the schematic.I'm fairly new to KiCad. I've been successful with a much smaller project, but this is my first attempt at something larger. Please would you look at the schematic / PCB and tell me if you spot anything wrong.Thanks in advance!EDIT: I will increase the space between the edge of the board and the edge of the battery holder by a few millimetres. Also, will there be any major problems with using a cheap PCB service like Elecrow for this board? I did design the trace widths around 35uM copper.

author: microbug
author_rank: Frequent Contributor
timestamp: July 29, 2015, 12:33:10 pm
content: Bump

author: microbug
author_rank: Frequent Contributor
timestamp: July 30, 2015, 10:14:24 pm
content: Last bump before I let this topic dissolve into obscurity.

author: amyk
author_rank: Super Contributor
timestamp: July 30, 2015, 11:35:22 pm
content: Why 4 single-cell protections, instead of one 4S protection IClike this one?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 31, 2015, 02:13:40 am
content: *Shrug* seems okay? One thing to look out for, that comes to mind: they won't all turn off at the same time, right? So if they're under heavy discharge, and one decides to open, and the others are normal, suddenly you have -12V across the one that's open. Is that okay for the controller and transistors?Is there an easy reset function? (Will it recover if current is reduced -- if so, by how much? Does the load have to be completely disconnected to allow leakage to restore voltages back to normal?)Tim

author: microbug
author_rank: Frequent Contributor
timestamp: July 31, 2015, 10:46:50 am
content: The controller can cope with -28V on V- and 12V on BAT, so it should be fine in fault conditions. The FETs are rated for a max of 30V across the drain/source, so they should be OK too.I chose to use 4 single-cell ICs because I couldn't find any 4-cell ICs that provided over/under voltage protection and over current protection. These ICs provide that.This is what the datasheet says about overcurrent release conditions:QuoteFrom that, my understanding is that the IC won't turn off overcurrent protection until the load is disconnected, or until a charger is connected. Overcurrent protection is more of a failsafe in my usage case: it's unlikely to ever kick in unless I accidentally short-circuit the pack!
PCB silkscreen symbol TTF font some advice - Page 1
Forum section: electronics / projects

author: sideshow bob
author_rank: Newbie
timestamp: September 10, 2025, 08:11:09 am
content: Hi all!I am working on a PCB silkscreen TTF font. See attached font map(work is still in progress). I plan to release it on here for freehttps://www.1001fonts.com/What I am unsure of is this symbolhttps://commons.wikimedia.org/wiki/File:ESD-warning-symbol.svgI have seen a lot of it on packing material. But not so much if ever on a PCB. What do you think should it be included??

author: Fire Doger
author_rank: Regular Contributor
timestamp: September 11, 2025, 06:39:46 pm
content: CE looks a bit thin

author: tggzzz
author_rank: Super Contributor
timestamp: September 11, 2025, 07:33:17 pm
content: Quote from: sideshow bob on September 10, 2025, 08:11:09 amI suggest you look at how silk screen characters are rendered on PCBs, and ensure your the details in your symbols will be legible.PCB manufacturers publish their "design rules", which will vary between manufacturers.
PCB spark gap - Page 1
Forum section: electronics / projects

author: marc1996
author_rank: Contributor
timestamp: July 11, 2018, 09:31:13 am
content: Hello to everyone, I have started to study about the PCB spark gaps and their utility. I'm doing an university project about that, related to the automotive ESD so I'm trying to recollect information about this.Something that I have been asking myself a lot is if there is or someone experienced a better formula about the breakdown voltage of the arc, considering more facts like humidity, dirty, etc...Also if someone have interesting information about PCB spark gaps, personal experience or whatever that can help me, I would be so thankful to read it.Thanks to everyone and sorry if my english is not that good!Marc

author: TimFox
author_rank: Super Contributor
timestamp: July 11, 2018, 07:00:14 pm
content: I believe that the breakdown voltage along a circuit board surface will not be well-determined. Normal spark gaps use the voltage between two electrodes separated by gas (possibly in a sealed package), where the “creepage” path along the insulating structure is very much longer than the air (or other gas) gap.
PCB stack for 3.3V and 1.18V power plane - Page 1
Forum section: electronics / projects

author: jtronix
author_rank: Regular Contributor
timestamp: September 28, 2015, 04:38:37 am
content: hello,two supplies are there in my Renesas microprocessor, how these suplies devide in power plane for multlayer PCB design???is there have any standard practice to design power plane for dual supply MPU for 4 layer PCB?My PCB stack:Layer 1: signalLayer 2: Power(3.3 & 1.18)Layer 3: GNDLayer 4: signalcan i use one layer for two supplies??please guide me for power plane design.

author: marshallh
author_rank: Unknown
timestamp: September 28, 2015, 04:52:58 am
content: https://www.practichem.com/blogs/Q5hSewfEB2q3ym9qX

author: jtronix
author_rank: Regular Contributor
timestamp: September 28, 2015, 05:02:20 am
content: i read the artical but could not found how to split two power plane in one layer..can you share more information

author: ConKbot
author_rank: Super Contributor
timestamp: September 28, 2015, 05:46:16 am
content: What are you doing? Your plane layout depends on your actual needs. Is it a 1.18 vcore and 3.3v io bank? Are either of them high speed? Are other things using either of the voltages?Assuming it's vcore and IO bank voltages, and both are high speed, (sort of worst case), your micro would be on layer 1, ground on layer 2, power on 3. Your 1.18v should be in a square under the micro just big enough that your decoupling caps (if they are on the same side) or vcc pins (if the de-caps are on the back) can punch right down to the plane. Keep the regulator close and plane running to it wide. The rest can be 3.3v. It might be a tiny bit fiddly to get it so the vcore and Vio pins can both connect by via right to a plane.If it's not high speed, io or core, your requirements relax. If

author: John_ITIC
author_rank: Frequent Contributor
timestamp: September 28, 2015, 05:49:34 am
content: Your 4-layer stackup completely depends on the current requirements from your ICs on the PCB as well as the impedance requirements on the outer layers. Technically, this is Power Integrity (PI) and Signal Integrity (SI) issues:PI: You must ensure that power is available with low inductance to all power pins. Decoupling capacitors are used for this purpose in combination with PWR/GND inter-plane capacitance (for very quick charge response to fast current spikes).https://en.wikipedia.org/wiki/Power_integritySI: You must ensure that there is a ground plane under the signals that can carry the return current. Make sure that your signals do not route over the splits in your inner PWR plane because this forces the return current to take a detour, increasing the loop inductance, impacting SI AND EMI.https://en.wikipedia.org/wiki/Signal_integrityOnce you have met these design criteria, you can split the planes any which way you want.The wiki articles are too thin on usable formulas etc but take a look here:http://www.thehighspeeddesignbook.com/If you want to buy a single book, I would recommend the above one. Note that there is a 2nd book in the series with more refined information.
PCB Stackup Question for high speed design - Page 1
Forum section: electronics / projects

author: the_torch
author_rank: Newbie
timestamp: July 08, 2025, 12:23:33 am
content: I am currently designing an 8 layer board (see photo). I am planning to route my DDR3 signals on the MIX_SIG3 and SIG4 layers, as this will keep the design as simple as possible(I. E. no messing will different dielectric constants because of using a mix of microstrips and striplines). However, you will notice that there is no GND plane between these signals, this isn't a problem as long as the Dielectric is thick enough between the layers, unfortunately, I have been unable to find a resource that could tell me whether 0.3mm is enough or whether I should have a thicker dielectric. Any tips would be greatly appreciated!
PCB standoff cover - Page 1
Forum section: electronics / projects

author: cio74
author_rank: Regular Contributor
timestamp: February 12, 2018, 02:51:46 pm
content: Hello,I would like to build a cover for a PCB project, that's it, a plastic sheet covering the PCB area, with 4 holes where the plastic standoff will fit and a map of the connectors printed on top of it. I was thinking of some sort of 1-2mm thick PVC/plastic that I can easily cut and print using an Inkjet printer.Has any of you tried such thing before, any recommendation?Thanks.

author: CopperCone
author_rank: Super Contributor
timestamp: February 12, 2018, 05:34:19 pm
content: its a good idea especially if its a module in a system because it can prevent something like a screwdriver tip shorting out a pcb during testing or calibration.A higher end solution would be to cut out an acrylic or plexiglass plate and glue transparancy paper to it.Also works as a blast shield for power electronics explosions and protects tou from mains.Of course ideally you should use a full metal shield to protect the circuit...
PCB stepper motor - Page 1
Forum section: electronics / projects

author: luiHS
author_rank: Frequent Contributor
timestamp: November 13, 2019, 05:16:34 am
content: Hi.I want to try to make stepper motors printed on PCB. I think there are important differences with conventional PAP motors with coils made of cableFundamentally, I am interested in knowing how to control these motors made with PCBs, in order to obtain the greatest number of steps and with it the greatest possible precision.In a conventional PAP motor, from what I have seen, between the stator and the rotor, there is something more complex than a magnet / coil coupling, to achieve a large number of steps. But in these PAP motors with PCB printed coils that is not possible, so we have the number of steps equal to the number of printed coils multiplied by two, to achieve intermediate steps by activating two adjacent coils at the same time.What is not clear to me is how many transistors are needed to activate a sequence of steps. For example, with a stator of 8 coils, I suppose we would have 16 possible steps, which is not much, and if I extend it to 16 coils it would have 32 possible steps.But how many transistors are needed to control the 16 coils printed on PCB and in which sequence they should be activated?I have seen that with 8 coils, they are activated 2 in 2, one coil and the opposite at the same time, and in other cases I have seen that with 12 coils, they are activated 3 in 3, and always in a sequence of 4, with which always use 4 transistors.With 16 printed coils, should I also use 4 transistors, how do I connect these coils and in what sequence do I activate them?On the other hand, I suppose that the way to increase the power with these motors, is by making larger coils, with more turns and putting bigger magnets, is that so? My idea is to use round neodymium magnets of at least 10mm in diameter, and increase the coils to the same diameter, with a 4-layer PCB that has each coil printed on each layer, connected in serial to increase the total number of turns.Regards

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: November 13, 2019, 06:47:54 am
content: Did you rotate that thing?

author: martin1454
author_rank: Regular Contributor
timestamp: November 13, 2019, 07:31:07 am
content: Check this project:https://hackaday.io/project/85502-pcb-stepper-motor

author: luiHS
author_rank: Frequent Contributor
timestamp: November 13, 2019, 07:48:42 am
content: Quote from: martin1454 on November 13, 2019, 07:31:07 amI already know that project, but it doesn't solve my doubts.
PCB stiching vias - Page 1
Forum section: electronics / projects

author: Nikos A.
author_rank: Regular Contributor
timestamp: May 26, 2021, 08:06:01 pm
content: Hi everyone,I'm looking a PCB design and I would like to know the reason of so many vias (stiching vias).I mean, are there any advantages of overflow the pcb with vias?In general this is a good practice?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 26, 2021, 08:30:07 pm
content: Reason? Because it's easy. A couple clicks in most enterprise tools.Is that just a demo board? Who cares about production cost, or routing density, it's one chip, an antenna and a bit of fanout...As for technical requirements, no it isn't important beyond a modest density (probably not even as many as they've used here) around the perimeter, and less density if any at all in unused areas. Same goes for the active element (antenna), which I'd probably just use a single layer for, likely no benefit to stitching bottom side (or middle) copper to it.Tim

author: ataradov
author_rank: Super Contributor
timestamp: May 26, 2021, 10:57:56 pm
content: To be fair this looks a bit nuts even for a prototype. 1/10 of this amount would be plenty.Also, it is not clear what is being stitched. I see traces, but I see no polygons. And the board does not seem to be complex enough to warrant 4 layers.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: May 26, 2021, 11:15:23 pm
content: The antenna also looks weird, with mounting holes on their side and the via stitching next to it.In well designed HF PCB's you sometimes see via stitching with a close pitch that follows critical impedance paths, and this PCB also does not have that.The via's here are just a plain simple grid that is interrupted wherever a track is laid, and the person who did this has probably put less thought into it then you have.My advise is to ignore this design (and the people who made it) and move on to some more sensible.

author: tkamiya
author_rank: Super Contributor
timestamp: May 27, 2021, 02:04:56 am
content: I can think of purpose of vias being1) connecting layers2) thermal dissipation3) isolation (guarding)4) stability in RF region5) current handlingA lot of times, small surface mount devices require under side to be copper and stitched to help dissipate heat. That could explain some of them. Areas AROUND the antenna makes sense for ground plane. But vias on antenna itself doesn't make any sense. As someone said, I think this was done without much thought.
PCB Switching power supply and digital signals - Page 1
Forum section: electronics / projects

author: AlexeyKH
author_rank: Newbie
timestamp: March 04, 2023, 08:10:48 am
content: Hello All,I'm new on this forum. Love the youtube channelI'm not an electrical engineer, so my questions maybe not correct one, so I apologies from beginningI design pretty tight PCB, that includes some processing unit and peripherals (digital part of the board).This board also includes buck converter to power the board.It is 4 layer PCB.I try to occupy maximum of the board surface, but my main concern is the buck converter (include all the magnetic parts).So this part of the PCB is clear from other components (bottom layer of PCB too) I try to avoid routing in this area too.my questions please :1. All my power supply parts are on top layer. Can I use the bottom part of the board (same location, beneath the power supply) for digital components/routing? Inner layers 1 and 2 are GND.2. Will the grounding of the inner layers be sufficient enough, so I can route signals on bottom layer? For general gpio signals? For high speed signals (USB3/PCIE)?3. On some designs I noticed that Power supply part is "disconnected" from main circuitry. It looks like a thin gap on pcb layer between the power supply and other electronics. Why do we need it? Since ground are still same for all pcb.Thanks

author: moffy
author_rank: Super Contributor
timestamp: March 04, 2023, 08:50:27 am
content: The thin gap or slot on the PCB could be for isolation purposes or it might just be a star connection to the PSU to prevent circulating currents in the PSU escaping and causing noise elsewhere in the rest of the circuit.

author: wasedadoc
author_rank: Super Contributor
timestamp: March 04, 2023, 11:18:17 am
content: Is there AC mains, eg input to the buck converter, on the board?

author: jonpaul
author_rank: Super Contributor
timestamp: March 04, 2023, 11:52:54 am
content: impossible to comment without a schematic and PCB layout screenshotsj

author: AlexeyKH
author_rank: Newbie
timestamp: March 04, 2023, 12:42:58 pm
content: No.Input is DC 12-24V

author: AlexeyKH
author_rank: Newbie
timestamp: March 04, 2023, 12:50:08 pm
content: This is the Power supply part of the board. (in attachment)As you can see, all components are located on top layer.Inner Layer 1 and 2 are groundCurrently bottom layer is also ground.I would like to put some components (resistors and optocouplers) on bottom side, just beneath the Power supply unit.Will two ground planes (inner layer 1 and 2) be sufficient enough from EMI and other parasitic noises?

author: Terry Bites
author_rank: Super Contributor
timestamp: March 04, 2023, 05:07:27 pm
content: It’s very unlikely that noise from the converter will couple into the GPIO lines and cause problems.You probably don’t need a ground plane to separate the GPIO either, but it’s a good idea if your PCB can accommodate it.
PCB Tarrifs for PCB's from China to US - Page 1
Forum section: electronics / projects

author: mgwalker95
author_rank: Contributor
timestamp: March 30, 2021, 02:36:59 am
content: Hi,The last time(April 2020) I ordered a PCB and had it assembled in china and then shipped to the US there was a 25%-30% tariff at customs. Are these tariffs on PCB's still in effect this year? What are some tips for importing PCBs?Thanks for the help!

author: KL27x
author_rank: Super Contributor
timestamp: March 30, 2021, 05:18:14 am
content: Curious, did your boards contain microcontrollers? There's a customs fee for importing microcontrollers from China. I don't know why else you would have been "taxed."After the boards clear customs and you receive them, you end up getting the bill a few weeks later.

author: mgwalker95
author_rank: Contributor
timestamp: March 30, 2021, 05:53:47 am
content: Yes, It did contain a Silabs MCU maybe that was the reason.

author: KL27x
author_rank: Super Contributor
timestamp: March 30, 2021, 08:13:51 am
content: Rumor has it that if you send microcontrollers to China for assembly, you can fill out some forms so that you don't pay any customs/tariffs. But I don't know anyone who knows how to do this.I actually used a local company, back in the olden days when I didn't know how to buy them direct from China, myself. I provided the microcontrollers to this local company. They sent the stuff to China and dealt with the fab. I got my boards.A few weeks later, the local intermediary sent me an additional bill for the customs fee. Apparently, this professional company didn't know how do do that, either.If anyone knows, that would be nice info!

author: Mecanix
author_rank: Frequent Contributor
timestamp: March 30, 2021, 08:19:26 pm
content: Done "legally" the Border Customs should not be adding import tax on the cost of the PCBs, but only on the cost of the components rather. If you have been taxed on the cost of the PCB you can claim this back.The US Trade Representative (USTR) has updated its list of imports excluded from tariffs under Section 301 to include 2- and 4-layer rigid printed circuit boards (Items 77 and 78). Under the new rules, the US will no longer levy a tax of 25% on those imports.

author: mgwalker95
author_rank: Contributor
timestamp: April 01, 2021, 04:52:16 am
content: Hi Mecanix,Thank you for the information, I does it also apply to boards other than 2 and 4 layer boards? where did you find that information?

author: Mecanix
author_rank: Frequent Contributor
timestamp: April 01, 2021, 10:58:17 am
content: Hi, mgwalker95The "unofficial" information concerning "Section 301 to include 2- and 4-layer rigid printed circuit boards (Items 77 and 78)"https://boardbuying.com/2-and-4-layer-pcbs-excluded-from-china-tariffs-you-may-be-entitled-to-a-refund/The "Official" information concerningHTS code: 85340000https://ustr.gov/issue-areas/enforcement/section-301-investigations/search^ however this returns unfriendly search result; a pointer to countless documents. (see visual)Recommend contacting your USTR for validity and additional details on #85340000. Tel/Hotline: (202)395-5725
Pcb Test Design - Page 1
Forum section: electronics / projects

author: Rasklnc
author_rank: Newbie
timestamp: May 16, 2024, 09:33:36 pm
content: I am making electronic circuit design but the PCB test takes a lot of time. I thought if I design a test circuit I could be earning time. What do you think about these project? Do you have any idea or how can I make ıt ?If I design test card only one circuit I can't use other design. I want to one card for the a lot of PCB card

author: Konkedout
author_rank: Frequent Contributor
timestamp: May 17, 2024, 04:58:24 am
content: I don't understand what you are requesting, and I guess others feel similarly. Are you trying to design a pcb to test a pcb? If you want a better response, please give more detailed information as to what you are trying to do.

author: Mark
author_rank: Frequent Contributor
timestamp: May 17, 2024, 09:32:37 am
content: Something like a home-made bed of nails jig?https://www.reddit.com/r/electronics/comments/albymi/built_a_bed_of_nails_test_jig_to_speed_up_testing/

author: tooki
author_rank: Super Contributor
timestamp: May 17, 2024, 10:23:56 am
content: I’m thinking they want a universal test bed.Such things already exist, but they cost a fortune.

author: aliarifat794
author_rank: Regular Contributor
timestamp: May 17, 2024, 05:58:39 pm
content: If you want an universal test bed like someone guessed here, you can make a PCB tester. A PCB tester will help you test all PCBs. You can perform short circuit test with a PCB tester. You can also check for broken traces with the tester. If will help you easily find faults with your PCB. You can make one such device following this design here.https://www.pcbway.com/project/shareproject/Miniature_PCB_Tester_c2b226d2.htmlIt's a miniature PCB tester. It is based on ATTINY45-20PU from Microchip Technology. While a simple project, one thing that seemed clever was the way that the two output pogo pins/LED was mounted. The 3D-printed fixture is designed to hold the LED leads like a spring.

author: tooki
author_rank: Super Contributor
timestamp: May 19, 2024, 08:34:40 am
content: Quote from: aliarifat794 on May 17, 2024, 05:58:39 pmBut that isn’t universal, it’s a classic tester that is specific to a PCB.
PCB test pads - when and where should they be placed. - Page 1
Forum section: electronics / projects

author: anishkgt
author_rank: Frequent Contributor
timestamp: January 19, 2018, 01:16:22 am
content: Hi All,Not sure if this topic is relavant here or should it go to the general chat.I am going to get my boards send to the fab house a few questions before i do.When and were are test pads to be placed ?who does it benefit, the manufactures or end users ?Are these necessary ?What pins on a MUC should those be or components ?

author: ataradov
author_rank: Super Contributor
timestamp: January 19, 2018, 02:06:27 am
content: If you don't know how you are going to use them, then you don't need them.Generally it starts the other way around, you figure out what you need to test/program, and the rest follows from that.And the placement is highly dependent on the scale of your manufacturing, and your ability to make jigs.

author: ajb
author_rank: Super Contributor
timestamp: January 19, 2018, 03:40:47 am
content: -The board fabricator doesn't need test pads, because if (IF!) they do electrical testing they can just use the existing pads and flying probes.-The board assembler doesn't need test pads unless you tell them they need pads in the test plan you send them. If you don't send them a test plan, they won't (be able to) test anything, so they won't. Some companies require 100% testing of assembled boards to verify component placements and check for shorts/opens, in this case you'll need a test pad for every net, or test equipment that can probe on placed parts.-You might need test pads while developing the device, but in that case you'll have to try to anticipate what you'll want to probe often enough to want a test pad.-End users probably never need test pads as a rule, unless your target market is engineers and your device is designed for them to tinker with it.As far as what signals to provide test pads for, a minimum would be one for each power rail, plus debug connections for MCU etc if there isn't a dedicated header. A serial port is nice for debugging, and generally if you have any unused pins on the MCU it's nice if you can at least bring them out to a test pad--spare IOs you can twiddle and watch on a scope are always nice. Anything else depends entirely on the application.Once you've decided what signals should have test pads, you'll need to discuss placement of them with whoever is doing the testing. If it's a contract manufacturer using their own equipment, you'll need to consult with them on what their capabilities are. If you're doing the testing, or designing a jig for a CM to use, then it's down to what sort of jig you're comfortable designing. Probably you want to at least keep all test pads to one side. But it all depends. If the test pads are just for development/debugging then make sure you can get to them easily when the device is in whatever configuration it needs to be in while developing it. For instance, if parts of the board will be shielded or obstructed by large components or displays etc then these are not good places for development test points.
PCB thickness for 3U backplane - Page 1
Forum section: electronics / projects

author: radar_macgyver
author_rank: Frequent Contributor
timestamp: July 01, 2018, 08:06:04 am
content: I have a design that needs a custom backplane for 3U Eurocards. Could I get away with the standard 1.6mm PCB thickness, or would I need to use a thicker and more expensive PCB? This would be purely for mechanical strength, not for signal routing. Connectors used would be DIN 41612, with coax pins. The backplane would fit inside a card cage, like a Schroff Europac:https://schroff.nvent.com/wcsstore/ExtendedSitesCatalogAssetStore/Attachment/SchroffAttachments/Documents/6_1_europacPRO_e_.pdfThanks in advance.

author: Benta
author_rank: Super Contributor
timestamp: July 01, 2018, 09:02:47 am
content: 1.6 mm is enough, that's what other backplanes are.

author: Siwastaja
author_rank: Super Contributor
timestamp: July 01, 2018, 10:21:06 am
content: Should be designed so that the connector plastic directs the insertion force into the case, so no PCB flexing occurs.

author: radar_macgyver
author_rank: Frequent Contributor
timestamp: July 01, 2018, 05:03:50 pm
content: Thanks for the replies!Quote from: Benta on July 01, 2018, 09:02:47 amSome examplesI found of commercial 3U backplanes indicated 4 mm thick backplanes, as did an old 6U VME backplane I dusted off at work. I suppose it could have been over-designed, or that VME requires higher layer count.Quote from: Siwastaja on July 01, 2018, 10:21:06 amThe enclosure drawings show the mounting holes to be 128.55 mm apart. The DIN 41612 connector mounting holes are 90 mm apart, leaving 15 mm of PCB on each side to take up the insertion force. Maybe I need to add a stiffener? The enclosure catalog shows a direct mount, see attached.

author: cat87
author_rank: Regular Contributor
timestamp: July 03, 2018, 02:54:18 pm
content: From what i've seem the 16mm backplane is quite stiff if you use the lower and upper bolt holes and shouldn't flex when inserting or removing a card. I have a few at home and none use a stiffener.Update 5.07.2018:I just tried attaching a bacplane to two z rails on a 3u 19 inch subrack to see how stiff everythong is. I bolted the backplane using both the holes for thw DIN connectors and the row of holes above those. I have to say it's rock solid.Can't really get to bendt it much even when applying more force than needed for card insertion.
PCB to PCB connector, 90°, 1.27mm pitch - Page 1
Forum section: electronics / projects

author: davorin
author_rank: Unknown
timestamp: February 18, 2025, 10:55:53 am
content: Good afternoon (o;Spent the whole morning at mouser and digikey sites to search for a components to connect a PCB vertically onto another PCB but without luck.Basically what I need is a 10 position connection with 1.27mm pitch and 2 rows.The bottom PCB should be a SMT socket and on the mounted PCB with a 90° header, preferably with a notch to protect for wrong polarity when plugging in.Like those small ARM SWD connectors for in-circuit programming with the according 90° socket.Just found something for 2.54mm pitch like the Sullins model above.

author: bigendian
author_rank: Regular Contributor
timestamp: February 18, 2025, 11:41:51 am
content: at least to exist they exist, seeing them herehttps://www.optimusdigital.ro/en/pin-headers/8899-2-x-3p-127-mm-smd-female-pin-header.htmlProbably 2.00 pitch is more common, or other kind of connectors

author: davorin
author_rank: Unknown
timestamp: February 18, 2025, 11:49:21 am
content: Guess I finally found something (o;Molex series 78120 and series 201021:

author: mtwieg
author_rank: Frequent Contributor
timestamp: February 18, 2025, 12:56:25 pm
content: Quote from: davorin on February 18, 2025, 11:49:21 amI'm actually surprised something like this exists in 0.05" pitch (outside of a fancy FMC connector with >100 pins), I'll have to remember these for future projects.I hope you don't plan on these connectors being the sole mechanical support for the board though. You'll want some external mechanical support which is also precise enough to allow the connectors to mate properly. Not as easy as it sounds.Also it looks like the female side has locking ramps, might want to file that down if you plan on unmating these often.
PCB trace impedances of integrated circuits with high input impedance - Page 1
Forum section: electronics / projects

author: electronx
author_rank: Regular Contributor
timestamp: May 13, 2024, 12:18:38 pm
content: There is an ADC front end IC (opamp) at the input of my ADC card and it has high input impedance, What should I set the differential trace impedance to when drawing the PCB? Does this matter much?

author: moffy
author_rank: Super Contributor
timestamp: May 13, 2024, 01:01:43 pm
content: For a 0-20kHz frequency range the trace impedance is not an issue, but if you have to run them any length keep them close to one another to reduce differential pickup.

author: shapirus
author_rank: Super Contributor
timestamp: May 13, 2024, 04:10:34 pm
content: It depends on the speed of the signal (edge rise/fall times), source impedance, and the length of the traces between the source of the signal and the ADC.What numbers are you dealing with in terms of the above?
PCB Trace Width for 10A Servo Motor - Page 1
Forum section: electronics / projects

author: K1JOS
author_rank: Regular Contributor
timestamp: November 19, 2014, 01:36:13 pm
content: I have a proprietary (no schematic) servo motor (12vdc, 10A startup) controller used outdoors that got zapped in a lightning surge. I have replicated the circuit that uses 4 MOSFETS (2 N and 2 P enhanced channel -- IRL540N and IRF 5210) in a H bridge controlled by as PIC18F MCU. I was surprised to see on the original board that the traces carrying the 10A +12vdc was only 2mm wide. I cannot tell how thick the copper plane is but it doesn't look any thicker than most of the PCB's for low voltage applications.Is 2mm wide enough or should the design be as wide as possible - like the large ground plane on the PCB bottom?thanks in advance for any advise

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 19, 2014, 04:04:33 pm
content: I would go with 2oz and 100-200 mil (2.5-5mm) width (or build the route out of polygons of similar average width).If that's 10A continuous, that is. If it's only pulsed for much shorter periods (0.1s?), you can get by with less.Tim
PCB track goes to two areas. How do you prefer to split it? - Page 1
Forum section: electronics / projects

author: tom66
author_rank: Super Contributor
timestamp: January 12, 2015, 10:15:48 pm
content: I have to split a low speed signal track out to two places. Routing through a pad won't work here. Either way, it just doesn't look "right" to me. What do others do when presented with this problem?Option 1. "Y" bendOption 2. Fork out 90 degreesOption 3. Via and fork outOption 4. Something else?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 12, 2015, 10:27:29 pm
content: What..?Oh, the trace on the right..? You didn't make it obvious what you were talking about... the screenshot isn't cropped around the subject, and the cursor and crosshairs aren't anywhere near it either...1. is undesirable because of acute angle.2. is fine.3. is also fine but wastes two vias and penetrates the ground pour.You can augment 2 by adding a triangle or diamond or fillet sort of thing (gussets or teardrops), but this isn't usually important. Sometimes, manufacturers will request that they add such features, though usually around THT pads (where the drill can miss and cut the annular ring apart from the trace).Tim

author: voja
author_rank: Contributor
timestamp: January 12, 2015, 11:26:33 pm
content: If there are no extra requirements, then option 2, of course
pcb transfers - Page 1
Forum section: electronics / projects

author: m3vuv
author_rank: Super Contributor
timestamp: June 20, 2019, 07:43:43 am
content: i remember a while ago maplin uk used to sell self adhesive pcp symbols for marking out copper clad before etching,can anyone remember what they were called,ive looked on ebay but cant remember what to search for!

author: alanb
author_rank: Frequent Contributor
timestamp: June 21, 2019, 01:06:15 pm
content: The name that springs to mind is Letraset. I remember both symbols for schematics and pads, lines and bends for PCBs. I've not seen or used them for about 40years.
PCB transformer rated power less than specified  - Page 1
Forum section: electronics / projects

author: danv
author_rank: Newbie
timestamp: March 19, 2014, 02:12:43 pm
content: We are using the transformer 3 VA 12V PCB transformer BVEL305 2052 .When measuring voltage current and power on a load of about 54 ohms I get a maximum power of 3W monetarily but when I leave the load for 5 hours to settle downthe max power is only 2.74W instead of 3W as notes in the data sheet even trying to vary the load to get the maximum powerIs it Ok, why is the rated power less than specifiedThank you

author: nerdyHippy
author_rank: Contributor
timestamp: March 19, 2014, 06:01:37 pm
content: Power = V^2/R. 12^12/54 = 2.7. Change your load and you will get a different amount of power.

author: danv
author_rank: Newbie
timestamp: March 20, 2014, 11:30:55 am
content: Thank you for the replayBut the max power delivered from the transformer was adjusted through a series of resistors to get the maximum power. So the point is that the transformer gives the rated power when cool, when it warm up the power decreases form 3 W to about 2.5W I would think it is to do withA short circuit-proof transformer is a transformer for which the temperature does not exceed established limit values when the transformer is overloaded or short-circuited and which continues to fulfil all the requirements of the Standard listed above once the overload or the short circuit has been eliminated.• An unconditionally short circuit-proof transformer is a short circuit-proof transformer without a protective device for which the temperature does not exceed the established temperature limit values in cases of overload or short circuits which can continue to be operated after the overload or the short-circuit has been eliminated. Note: Due to physical limitations, this kind of transformer permits only structural designs with low levels of rated power of up to circa 4 VA. The open-circuit voltage factor can thereby take on a value of up to 2.00. The shape of the curve of the output voltage can deviate from the sinusoidal form. It is not mandatory that unconditionally short circuit-proof transformers need be permanently short circuit-proof.• A conditionally short circuit-proof transformer is a short circuit-proof transformer with a built-in protective device, which opens the electrical circuit or limits the electricity in the input or output circuit when the transformer is overloaded or short-circuited. Note: Examples of protective devices are fuses, overload releases, temperature fuses, automatic and non-automatic resetting temperature limiters, posistors and automatic mechanically-triggered protective switches.A non-short circuit-proof transformer is a transformer which is intended to be protected against excessive temperatures by means of a protective device which is not built into the transformer
PCB USB PLUG - Page 1
Forum section: electronics / projects

author: wreeve
author_rank: Unknown
timestamp: September 11, 2015, 03:41:41 pm
content: Has anyone got a design for a PCB footprint you can plug directly into a USB socket; I've seen a number in the wild, as a business card for instance, but I wondered if there is any specification (official or otherwise) on the pads and PCB thickness / dimensions which work reliably. Anyone ever done it?

author: amyk
author_rank: Super Contributor
timestamp: September 12, 2015, 03:24:36 am
content: Look in the USB spec; I think I've seen the dimensions in there.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 12, 2015, 07:24:04 am
content: Or just pull apart a USB plug and measure it.

author: jc101
author_rank: Frequent Contributor
timestamp: September 12, 2015, 07:54:57 am
content: I've got an FTDI module which is just a bare board to plug into USB A sockets, the data sheet has some dimensions on it but not the pads themselves...http://www.ftdichip.com/Support/Documents/DataSheets/Modules/DS_UMFT201_220_230XB.pdf{Page 8}Meaning the pads, and this will be approximate, the outside ones are 1.75mm x 11mm with the inside 1.25mm x 10mm.Combine this with page 99 of the following and you should have all the dimensions needed to create a layouthttp://www.usb.org/developers/docs/ecn1.pdf

author: LukeW
author_rank: Frequent Contributor
timestamp: September 12, 2015, 08:43:57 am
content: Those Cypress CY8CKIT-049-42XX boards are super cheap, like $4 or something. So if you can't get the info from their open-source files you could always just buy one and measure it.Also:https://github.com/freetronics/LeoStickI just measured the thickness of a LeoStick and a Cypress PSoC board at the USB connector... they're 1.9mm.
PCB UV box - Page 1
Forum section: electronics / projects

author: Deathwish
author_rank: Unknown
timestamp: June 05, 2015, 08:16:12 am
content: I purchased one of those UV nail curing boxes a while back, I got it for setting LOCA , but I am now wondering if I could gut it or get another to gut for use in a PCB exposure box. At the cost of around £14 for the unit itself which has an inbuilt timer as well as the lamps it would be worth it too me rather than spend more on separate components, BUT, yep always one of those isnt there, would the wavelength of those lamps be good for the job ?.I have the idea of purchasing a aluminum case/box, some 12mm batten and a piece of glass to put the lamps under and the pcb onto for exposure, possibly even lamps on top in the lid for double sided single exposure and a double sheet of glass to sandwich the pcb and circuit in as exposing.

author: sleemanj
author_rank: Super Contributor
timestamp: June 05, 2015, 08:35:49 am
content: Yes the wavelength is fine. See bigclive's videos on the subject, first 3 results herehttps://www.youtube.com/results?search_query=bigclivedotcom+nails

author: Deathwish
author_rank: Unknown
timestamp: June 05, 2015, 08:36:56 am
content: Oooh I like vid's, thank you for that one.

author: Deathwish
author_rank: Unknown
timestamp: June 05, 2015, 08:50:28 am
content: You just made my day. Thank you.

author: Canobi
author_rank: Regular Contributor
timestamp: June 08, 2015, 10:12:31 am
content: I made an exposure box with one of those just recently. I used an aluminium briefcase to house everything and used the glass bed from a flatbed scanner.Works a treat and don't often need more than two mins so the timer is perfect

author: Quiggers
author_rank: Contributor
timestamp: June 09, 2015, 12:20:19 pm
content: About to use two uv note checkers to do a similar thing. Small PIC (12F675) and a relay as control or maybe a 555.

author: Deathwish
author_rank: Unknown
timestamp: June 09, 2015, 12:29:42 pm
content: Sorted !, love it, I love doing such things when i can.