hybridfree/eevblog-posts huggingface dataset:
Requesting office hours / tutor - Page 1
Forum section: electronics / projects

author: ibash
author_rank: Newbie
timestamp: July 19, 2021, 12:50:04 am
content: I just got done designing a pcb based on a few other designs.As a beginner I’d love to have a 1-2 hour video call where I can take you through the design, and the schematics they’re based on, and ask questions about things I don’t understand. Sometimes it’s just way better to have a quick back and forth about a topic.I’ll happy take the names of topics I should learn about and go do my homework, but sometimes it’s hard to know the right question. Examples of questions I’d ask:“Why in this schematic do they set one resistor at 5.1k and this other one at 1.5k?”“What’s this ferrite bead doing here? Is it arbitrary?”“Can I choose whatever pins I want on this stm32 in this design? Or is there a reason one might prefer one over the other?”“What are all the things that might go wrong in this design that I’m not seeing?”This doesn’t need to be reoccurring, a one off would be super helpful. Happy to make it paid as well. Im in pacific time.Is anyone up for a 1-2 hour q&a?

author: ataradov
author_rank: Super Contributor
timestamp: July 19, 2021, 01:07:42 am
content: If you can do it today around 9 PM Pacific, then I'm up for that.If that works for you, PM me an invite link to any conference system that works in a browser and does not require registration or account (probably anything but Teams).

author: ibash
author_rank: Newbie
timestamp: July 19, 2021, 01:11:54 am
content: Hey thanks!

author: ibash
author_rank: Newbie
timestamp: July 19, 2021, 05:00:52 am
content: Thanks again! Came away with a lot of things to read up on and way more confidence in what's going on. Super appreciate it!
Required pin diagram for DIL8W/SOIC8 ZIF 200mil SFlash-1a - Page 1
Forum section: electronics / projects

author: jtronix
author_rank: Regular Contributor
timestamp: March 17, 2020, 07:30:44 am
content: Hi,I need pin diagram for programming adapterDIL8W/SOIC8 ZIF 200mil SFlash-1a. I have Elnec Beeprog+ programmer.Basically I want to program S25FL128 QSPI Flash without purchasing adapter because at this stage I'm evaluating the chip.Adapter Link:https://www.elnec.com/products/programming-adapters/DIL8W_SOIC8_ZIF_200mil_SFlash-1a/?utm_source=sw&utm_medium=searchNote: Same adapter is used for Datacom, Elnec and BK PrecisionCan anyone check their adapter and share the diagram?

author: jtronix
author_rank: Regular Contributor
timestamp: March 19, 2020, 10:03:18 am
content: Anyone have adapter?
Requirement to release schematics for Canadian CE mark? - Page 1
Forum section: electronics / projects

author: Pack34
author_rank: Frequent Contributor
timestamp: July 13, 2016, 02:43:42 pm
content: We're looking at going through another company to get the equivalent of a CE mark in Canada and they're asking for full schematics. Is this typical? We're using a certified power brick so it should just be emissions, correct?

author: AndyC_772
author_rank: Super Contributor
timestamp: July 13, 2016, 03:35:32 pm
content: Is your product - or, more specifically, couldanyproduct powered from that PSU - ever start a fire? Or cause a high voltage to appear on something user-accessible?If you're asking a safety lab to assess your product, then they need schematics. It's an entirely reasonable request, and they'll probably ask for your BoM and build instructions too, as well as any other relevant information about your safety critical parts (fuses, isolating components, MOVs and so on).

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 13, 2016, 04:21:05 pm
content: I've been asked for fab drawings prepared in a certain way. Dunno if schematics were needed, but I guess they didn't need modification from as-provided.Tim
ResCalc - Custom Valve Resistor Search Calculator - Page 1
Forum section: electronics / projects

author: mucek
author_rank: Contributor
timestamp: May 01, 2014, 06:08:03 pm
content: Hi there!Elektronik.si is Slovenian electronics forum and its member Gumby created very useful program, which calculates potential candidates for a custom valve resistor using resistors from "standard" E (12, 24, 48, 96) sets. In the first post onhttp://www.elektronik.si/phpBB2/viewtopic.php?t=39603&start=0you can find last version of the program (also included in ZIP here).Regards,Gregor

author: electr_peter
author_rank: Unknown
timestamp: May 01, 2014, 06:39:51 pm
content: Hi,Program seems to be nice and simple, but there are many alternatives on www, for examplehttp://www.wolframalpha.com/input/?i=1234+Ohm

author: codeboy2k
author_rank: Super Contributor
timestamp: May 01, 2014, 08:19:08 pm
content: Quote from: electr_peter on May 01, 2014, 06:39:51 pmmind blown.

author: SArepairman
author_rank: Frequent Contributor
timestamp: May 01, 2014, 09:46:08 pm
content: my mind is too blown by the wolfram linki admit brute forced solutions on a piece of papercan the wolfram do E higher then 12?

author: sleemanj
author_rank: Super Contributor
timestamp: May 01, 2014, 11:13:35 pm
content: See also my own athttp://sparks.gogo.co.nz(choose it in the top menu bar there, i'm on mobile and can't remember the exact url), it works from your personal "stock list" rather than assuming you have any particular value(s) available, only takes a few seconds to define your stocklist (base values and num of usual decades of those, missing vals from those decades, and extras not in those decades) then "save" it for future.
research in connectors/novel designs? - Page 1
Forum section: electronics / projects

author: coppercone2
author_rank: Super Contributor
timestamp: December 23, 2018, 03:56:18 am
content: What are the frontiers of connectors? Is there any upcoming designs and research or things to be excited about?Two things that come to mind:1) integrated x2y capacitors in filters2) is it possible to implement spark gaps in connectors to offer protection?3) magnetic latching4) self cleaning from dirtwhats the connector of the future look like?
Reset esp8266 when circuit *broken* with minimal power draw at rest - Page 1
Forum section: electronics / projects

author: puterboy
author_rank: Regular Contributor
timestamp: April 18, 2024, 05:00:14 am
content: I am using an esp8266 to monitor the continuity of a loop of wire (for an alarm).When the loop is cut, I want to awaken the esp8266 from deep sleep and process the alarm signal.I want to minimize power drain during the deep sleep phase to preserve battery power.Note that the esp8266 typically awakens by driving RST low (e.g., grounding it) to create a HI->LOW transition.Basicaly I need something to "invert" the signal so that cutting (i.e, interrupting) the signal will create an output that acts as a "sink" and drives RST low.Using a pulldown resistor will surely draw too much current at rest.Other choices I have considered are:- One-shot/Monostable chip?- Microcontroller?- Discrete transistor circuit?- MOSFET circuit? (with one end of loop grounded and the other end going into the GATE with high value resistor to VCC and RST attached to SRC with DRAIN grounded so that when loop is broken, gate is pulled high and and source is driven low)Note total loop resistance is about 50-60 ohms (it's a 200ft+ loop of thing gauge wire)So what circuit & components would you recomend so that current draw is minimized when monitoring loop before cut?
Reset IC Recommendations - Page 1
Forum section: electronics / projects

author: craigfoo
author_rank: Contributor
timestamp: March 27, 2014, 07:53:08 pm
content: Are there any parts out there that will perform the following function?When a pulse that is sitting at 0 goes to 1, I want to trigger an output that will go from 0 to 1 then back to 0 around 200ms later on it's own. How could I accomplish this?See attached picture for illustration.

author: craigfoo
author_rank: Contributor
timestamp: March 27, 2014, 07:59:36 pm
content: As in a 555 timer in monostable mode?

author: Rick60
author_rank: Contributor
timestamp: March 27, 2014, 08:25:29 pm
content: You haven't given a voltage for in and out would a TPS3837 power on reset chip fit the bill ?

author: craigfoo
author_rank: Contributor
timestamp: March 27, 2014, 08:29:36 pm
content: Thanks for the suggestion but that's not going to work. The input is monitoring the output of a logic gate and it's output is dependent on the output of the chip I'm trying to use (probably a monostable 555 timer).The supervisory chip you mentioned will only assert the reset when the input changes.

author: tree
author_rank: Regular Contributor
timestamp: March 27, 2014, 08:52:16 pm
content: Try the MAX803. It can give you a pulse up to 140ms.
Simple ESP8266  with power module resets - Page 1
Forum section: electronics / projects

author: markus1234
author_rank: Newbie
timestamp: January 31, 2017, 05:26:59 pm
content: Hello,I want to build a small wifi in wall switch which just switches a relay on or off. For simplicity I have taken a HLK-PM03 (http://www.hlktech.net/product_detail.php?ProId=59) since it's easy to use and small. This power module will power a ESP8266-03 which than will switch a relay (by using a transistor).My schematics:This work pretty well in any room but in the kitchen - there it will randomly reset. Also if I just touch the ac at the terminals or the power outlet below, it will reset. Does someone know why?thanks in advance

author: TheDane
author_rank: Regular Contributor
timestamp: January 31, 2017, 07:00:17 pm
content: A decoupling capacitor (or several) might be what's missing, and causing your stability issues.From the AC-DC converter datasheet it states:Output ripple and noise: ?70 (mVp-p)Rated input voltage, full load. Using 20MHz of bandwidth,The load side 10uF and 0.1uF capacitor to be tested.Your schematic shows no caps at all. A 10µF and 100nF cap is required, be sure the voltage rating is okA kitchen tends to be grounded quite well, and since your body works great as an antenna - touching electronics can cause large voltages (and currents) that easily can (and will) cause resets, etc. when no ESD components has been fitted.https://en.wikipedia.org/wiki/Electrostatic_dischargeBuild it into a case, touching mains AC isn't for beginners - and isn't recommended, even for advanced geeks

author: markus1234
author_rank: Newbie
timestamp: January 31, 2017, 09:42:21 pm
content: Hi,thanks for the fast answerI tried that right now and added a 10uF and a 100nf cap right after the 3.3v output of the power brick (in parallel - with 1 cm of wire).The problem still exists (althought it seems to be getting better)

author: jm_araujo
author_rank: Regular Contributor
timestamp: February 01, 2017, 12:50:54 pm
content: You should also use a base resistor in Q1, and a flyback diode across the relay coil.Leaving those out will give you problems when switching the relay!
Resetting Write Protect (WP) bit on MCP46XX digital potentiometer - Page 1
Forum section: electronics / projects

author: fedeza
author_rank: Newbie
timestamp: March 10, 2023, 01:20:54 am
content: Hi all,I'm a noob here, so apologies if my question may seem a bit simple.I am using a MCP4661 10K digital potentiometer (Microchip, datasheet found here:https://ww1.microchip.com/downloads/aemDocuments/documents/OTH/ProductDocuments/DataSheets/22096b.pdf) and I'm interested in writing a value into the non-volatile register for wiper 0 or wiper 1. On my PCB, the WP* pin on the IC (active low) is connected to a GPIO of my MCU and set high (3.3V), whereas pins A0, A1, A2 are tied to ground (connected to ground plane using vias underneath pads) to assign the slave address for I2C (I am using 2 units of this digipot on the same I2C bus).My question is: how can I reset the internal WP bit so that I can write to the memory, please? I read the datasheet over and over again but I am just more confused. Should I put a high voltage (8.5V-12.5V) on the WP* pin or on the A0 pin before I send the I2C command to reset the WP bit? Or should I do something else? I just can't figure it out.Any suggestion is very much appreciated, please!

author: DavidAlfa
author_rank: Super Contributor
timestamp: March 10, 2023, 03:02:13 am
content: Basically, yes. Also read22107B, page 20

author: fedeza
author_rank: Newbie
timestamp: March 10, 2023, 09:34:37 am
content: Hi DavidAlfa,Thanks for your help. I had a look at the datasheet you linked and that is in fact the one I meant to include the link for since I'm using the Nonvolatile Memory MCP4661, so apologies for that. I'm not too sure which section of page 20 you're suggesting I should look at. Could you specify which graph, please?Regarding my issue her:1. The WP* physical pin tied to 3.3V is effectively useless and is not sufficient to reset the WP bit?2. If I were to connect the WP* to my 12V supply, would that be enough to be able to write to the memory? Or would I still need to put high voltage onto A0 and send the below command to register 0x0F to achieve that? Or both simultaneously maybe?Thanks again!
Residential wiring in India - branch circuit fuse or circuit breaker rating? - Page 1
Forum section: electronics / projects

author: Jester
author_rank: Frequent Contributor
timestamp: February 14, 2017, 07:15:22 pm
content: A typical 120V branch circuit in USA/Canada uses a 15 or sometimes 20A fuse or breaker. Anyone from India that would know what a typical branch circuit fuse rating is?

author: SeanB
author_rank: Super Contributor
timestamp: February 14, 2017, 07:58:29 pm
content: Well, as South Africa and India use the same ( UK derived) plug and socket, and here you typically use a 20A breaker, with a socket rating of 16A, I would guess the same applies. 2.5mm wire as well for the cable, though depending on exactly who did the install these can be all disregarded quite often.Breaker is rated to protect the cable, and the cord to the appliance must be able to handle the short circuit current for longer than the breaker trip time.

author: Jester
author_rank: Frequent Contributor
timestamp: February 14, 2017, 10:22:07 pm
content: Quote from: SeanB on February 14, 2017, 07:58:29 pmThank you that's helpful. I'm guessing when you say 20A breaker and 16A socket rating, the actual socket is rated 20A, but is de-rated to 16A? Much like they only put 12 lights on a 15A circuit in N/A. Well those were the rules back in the 70's when I played with residential wiring in high school, may have changed now.

author: RGB255_0_0
author_rank: Frequent Contributor
timestamp: February 14, 2017, 10:58:04 pm
content: Quote from: Jester on February 14, 2017, 10:22:07 pmSounds right. In the US you're not allowed to continuously draw more than 80% than the socket is designed for. Math works out for the 16A.

author: kaz911
author_rank: Super Contributor
timestamp: February 15, 2017, 08:31:04 am
content: Hmm have you seen wiring in India?..... CB's??? not that many.....

author: Miyuki
author_rank: Frequent Contributor
timestamp: February 15, 2017, 09:32:24 am
content: Quote from: kaz911 on February 15, 2017, 08:31:04 amThat reminds me thisvideo (warning it can be racist for someone), she telling about how cables was connected to steal electricity
Solved, obsolete. - Page 1
Forum section: electronics / projects

author: evb149
author_rank: Regular Contributor
timestamp: June 22, 2022, 05:49:39 pm
content: Solved, obsolete.

author: ajb
author_rank: Super Contributor
timestamp: June 22, 2022, 07:11:14 pm
content: https://www.mcmaster.com/multi-cord-grips/Specifically this style seems most like what you want:https://www.mcmaster.com/cord-grips/low-profile-wet-location-break-through-multi-cord-grips/Many of those have little 'punch through' seals over the holes, so very easy to add a new cable. There are also split grips, where there are two rubber pieces that get pressed together around the cords, which would generally provide better grip at the expense of taking slightly more effort to add cables.For trimming it out, there are mounting blocks designed to work with vinyl siding and provide a nice trim ring around the box. They usually have integrated flashing to keep water from getting behind the siding, and some have an integrated electrical box while others are designed to go over top of a standard box mounted in the sheathing:https://www.homedepot.com/p/Ply-Gem-8-5-in-x-7-5-in-Khaki-Electrical-Mounting-Block-EBLCKHN4H/202674765?source=shoppingads&locale=en-USFor my house, I couldn't find a mounting block that would go where I wanted because of the way our siding lines up to the rim joists. Instead I bought a chunk of 1x6 PVC trim board and ripped it to an angle that matched the siding, so that it would provide a plumb face when screwed and siliconed to the siding, and then I mounted surface mount boxes on the front of that. You could just as easily use a similar method but install a box behind the trim piece for a more flush solution. Either way I would probably want a box on the outside to avoid creating any paths for critters to find their way into the house around the trim block.

author: themadhippy
author_rank: Super Contributor
timestamp: June 22, 2022, 07:30:44 pm
content: Here in the uk id use a bit of plastic conduit,either 20mm or 25mm through the wall , back entry into a stop end boxon the outside,spout pointing down , add a bead of silicone around the box before screwing it to the wall to keep water from getting in,job done
Residual current device  - Page 1
Forum section: electronics / projects

author: Red_Micro
author_rank: Regular Contributor
timestamp: September 10, 2020, 12:42:50 am
content: I'm just checking this device from ABB:https://library.e.abb.com/public/56f56bae475a5325c1257d50002d806f/2CSC444001B0201.pdfThe document says:QuoteSince this is an earth leakage device, it must respond extremely quick. But I'm wondering if this can be quick enough as it does RMS. Usually, if one wants to capture both 50Hz and 60Hz, we would want to capture at least 5/6 cycles (100 ms) of the signal to get good RMS. Isn't this too slow for this kind of protective?

author: uer166
author_rank: Super Contributor
timestamp: September 10, 2020, 05:00:03 am
content: Define "extremely quick". The required timing ranges massively depending on standard, anywhere from 20ms to10 seconds. Consider that even at 20ms one can measure the RMS current, maybe not accurately, but at those high leakage currents levels nobody cares.Some other food for thought is Type B RCCBs that have to respond to DC, 60Hz AC, and even high-frequency 2kHz AC leakage.

author: Gyro
author_rank: Super Contributor
timestamp: September 10, 2020, 11:15:35 am
content: The required trip time for a Type B RCD at 5 times rated leakage current (i.e. 150mA) is amaximumof 40ms, which is two mains cycles at 50Hz. In practice, they trip in about half that. Tripping at 30mA is typically pretty similar. That doesn't leave much time for RMS conversion.Industrial stuff is no doubt different - from the look of the brochure you linked they seem to have an adjustment for instantaneous to 5s.

author: Red_Micro
author_rank: Regular Contributor
timestamp: September 10, 2020, 12:03:20 pm
content: Quote from: Gyro on September 10, 2020, 11:15:35 amInstantaneous often mean ~30 ms or less in type A&AC RCDs. That's why I wonder how they perform RMS for both frequencies in that short time.

author: Gyro
author_rank: Super Contributor
timestamp: September 10, 2020, 12:46:50 pm
content: I assume at that timescale it's an a mean/peak approximation. A fair chunk of that time is going to be taken up mechanically opening the contacts. They probably get into more clever RMS stuff for the longer trip times.

author: Zero999
author_rank: Super Contributor
timestamp: September 10, 2020, 01:04:04 pm
content: Why don't you ask the manufacturer?I suspect they don't calculate the RMS current, but use the peak current fed into a low pass filter.

author: Jeroen3
author_rank: Super Contributor
timestamp: September 10, 2020, 01:14:34 pm
content: "instantaneous" for these units is around 50 to 100 ms. Can't go much faster otherwise closing of the breaking or downstream switching may trip it already.It's also possible to calculate a moving rms value, which is probably what they do.
Residual light comming from LED Driver - Page 1
Forum section: electronics / projects

author: lmagalhaes
author_rank: Contributor
timestamp: February 10, 2022, 11:47:04 am
content: Hi there,I've designed a LED board with multiple colors (true green, deep blue, white 5000k, etc) and am using individual LED drivers for each color. The LEDs are "sprinkled" around the PCB, which uses aluminum as the dielectric for better dissipation. I'm using DALI to control the dimming of the various drivers, but some of them, when turned OFF, leave some of the LEDs glowing. Only after removing the phase connection the leds stop glowing. Either that or disconnecting both outputs (LED+ and LED-). Leaving the phase connected with the neutral disconnected, the LEDs keep glowing, leaving both the phase and neutral connected and just disconnecting LED+ leaves the LEDs glowing too. I don't think it's a case of a faulty LED driver since I've switched the drivers between themselves and the problem keeps happening. The heatsink where the PCBs are screwed down to is connected to Earth, but I have also tried disconnecting the earth wire and nothing changed. I am going to try and add some capacitors to the input, but don't think it's going to help much.Any ideas?

author: FlyingDutch
author_rank: Regular Contributor
timestamp: February 10, 2022, 12:32:57 pm
content: Hello,if you have LED of high brightness than can be glowing with liitle current (even fractions of microamperes). Your LED drivet IC might to produce such small currents on it's outputs - hence the behavior of the circuit.You can try use diodes conected in parallel to LEDs and resistors (serially and parallel). You have to experiment with your circuit to get best behavior of it.Best Regards

author: Siwastaja
author_rank: Super Contributor
timestamp: February 10, 2022, 12:43:40 pm
content: Try a resistor in parallel with LED. Assuming the leakage current is really small, huge value like 100-470kOhm will solve the issue without causing any meaningful extra power consumption.The tiny leakage current will then flow through that resistor, creating a small enough voltage drop so that the LED does not light up.If the LEDs are brightly on, or a say 100kOhm resistor in parallel does nothing to it, then there is probably something more seriously wrong.

author: lmagalhaes
author_rank: Contributor
timestamp: February 11, 2022, 12:47:13 pm
content: I added a 249k ohm resistor in parallel with the output of the LED Driver, still the LEDs keep glowing ... If I disconnect the LED+ of the driver, the LEDs glow even brighter, just like they are on. Any ideas?

author: FlyingDutch
author_rank: Regular Contributor
timestamp: February 22, 2022, 05:49:05 pm
content: Hello,you can try adding diodes (normal not Schotky) in paralel to LEDs. You can also try resistor in series with LED.Best Regards
Resin Splice On Shielded Cable? - Page 1
Forum section: electronics / projects

author: klr5205
author_rank: Regular Contributor
timestamp: August 05, 2020, 01:46:06 pm
content: I have a cable intended to go underwater that I want to wye-off into 2 different whips near its end. The cable consists of 5 individually shielded pairs (2 tiny motors and 1 resolver)My first thought was to use a resin splice similar to this product from 3M:https://www.3m.com/3M/en_US/company-us/all-3m-products/~/3M-Scotchcast-Wye-Resin-Splice-kit-82-B1N-1-5-kV-Non-Shielded-10-Case/?N=5002385+3291144871&rt=rudHowever the very first bullet on the webpage states that it is for unshielded cables only. Can anybody say why this is?Any other products out there that would be appropriate to splice 3 underwater cables together that can be done in house without any super specialized equipment? I only intend on making 2 such connections so farming it out somewhere might not be very cost-effective however I haven't gotten far enough to seriously look into that yet.

author: geggi1
author_rank: Frequent Contributor
timestamp: August 08, 2020, 07:38:49 pm
content: I have used similar stuf for ROV thethers and umbilicals. The thing about screens is that the kit proably dont come with the bits to run it through the splice. if the screen is copper mesh just solder the mesh together end your probably good if the signals running through them are not tcritical for noise. If noise is critial get some coppper mesh on roll and wrap this around the wires before assambling the shell and pouring the potting.
Resistance and Capacitance for any 2D shape - Page 1
Forum section: electronics / projects

author: zofz
author_rank: Regular Contributor
timestamp: April 29, 2015, 07:32:23 am
content: Maybe that solves no real life problems at the moment, but it looks interesting. The are two small pieces of software.Resist2Dshows a voltage drop and a current flow in the flat arbitrary surface (e.g. PCB track or flat thin film resistor like inhttp://www.eevblog.com/2015/04/04/eevblog-730-thin-film-resistor-networks/)Cap2Dshows a charge density and a potential/voltage in the two layer capacitor cross-section, for two arbitrary 2D shaped plates (png or other bitmap defines the shapes).Downloadhttp://www.zofzpcb.com/Resist2D.htmlhttp://www.zofzpcb.com/Cap2D.html

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 29, 2015, 03:28:13 pm
content: There's also ATLChttp://atlc.sourceforge.net/for the ideal impedance of an arbitrary cross section transmission line.Tim

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: April 29, 2015, 03:36:28 pm
content: Quote from: zofz on April 29, 2015, 07:32:23 amSweet. Thanks.
Resistance measuring IC to interface with MCU - Page 1
Forum section: electronics / projects

author: rosak
author_rank: Contributor
timestamp: November 19, 2019, 06:54:14 pm
content: Hi,I'm looking for a simple IC to measure resistance and communicate with MCU like STM32 or Atmega via I2C/SPI/UART.Basically the same thing as on ordinary multimeter but with only resistance measurement with scale up to 1kOhm.I know I can do that using voltage divider and analog input of MCU but in my application it becomes overly complicated. I'm hoping to find similar solution to tiny INA219.Thanks in advance for any help.

author: GeorgeOfTheJungle
author_rank: Super Contributor
timestamp: November 19, 2019, 07:49:24 pm
content: MAX31865?
Resistance of internal trace polygon copper pour  - Page 1
Forum section: electronics / projects

author: jonwilhelmjr
author_rank: Regular Contributor
timestamp: December 01, 2020, 06:01:16 pm
content: I am new to Altium and for work i need to determine the "rule of thumb" based trace resistance of all the copper in the design. Some of the traces are polygon. Some of the traces are internal and some external. Yes its 4 layer. I am doing a worst case circuit analysis. I need to show my math, so equations are required. Can any one suggest a tool or script to calculate the resistance? Maybe export the gerber to a script and determine the resistance. My main goal is to determine the voltage drop of the trace. Thank you in advanced for any help.

author: jonwilhelmjr
author_rank: Regular Contributor
timestamp: December 01, 2020, 06:45:17 pm
content: I would like to point out that these two websites are very helpful.https://www.eeweb.com/tools/internal-trace-width-calculator-pcb/https://www.eeweb.com/tools/external-pcb-trace-width/so that covers the equations, but that leaves the question how to apply it to a polygon and Altium? I think after this project I will try to write a script but is there anything i can use right now?

author: phil from seattle
author_rank: Super Contributor
timestamp: December 02, 2020, 04:13:28 pm
content: I would simply just take the narrowest point and use that as a trace width. There may be other geometrical shapes you could use rather than a simple long and narrow rectangle, though. It gets complex quickly. I'm sure that leaves current capacity on the table because the charts and calculators factor in a 10C heat rise which will be lower with more radiating surface area.

author: mag_therm
author_rank: Frequent Contributor
timestamp: December 02, 2020, 09:03:03 pm
content: Voltage drop of a trace.Here is a quick lash up of a "problematic" trace in QuickField with sharp corners and holes.The top is grounded.The bottom of the trace is supplied from a 10 Amp peak current source.The long vertical part is 2 mm wide. Copper thickness ( into page) is 35 micrometre with rho = 22e-9 Ohm.metre.The AC Conductivity model is run at 10 Hz.The color graph shows the current density.Using the probe, the voltage at the current source is 0.283 Volt peak ( as highlighted).R_trace = V/I = 0.283/10 = 23 milliOhmI have not tried, but it might be feasible to turn off all the tracks except the ones needing examination,and import that layer as a .dxf into the 2D. Then a number of tracks could be examined in one solution.

author: Siwastaja
author_rank: Super Contributor
timestamp: December 04, 2020, 09:03:47 am
content: For pours, mentally divide it in squares that are in series, count the number of squares. Sheet resistance of the typical ½oz inner plane foil is approx. 1mOhm/sq. Multiply by the number of squares.For example, if you have a large unbroken area say 5x5cm, another separate 5x5cm area, and a tiny 0.2mmx0.2mm neck connecting them, the resistance across both areas and the neck is 3 squares * 1mOhm/sq = 3mOhm.
Resistive behaviour using a buck - Page 1
Forum section: electronics / projects

author: snoop33
author_rank: Contributor
timestamp: January 28, 2023, 01:42:05 pm
content: Hi,What would be your method for implementing a buck that simulates a resistor feeding into a large super-capacitor?My end goal is to set a resistive equivalent load by MCU DAC. My initial thoughts were to use an op-amp deriving a target using the dc & dac, which is compared to a high current sense, which drives either a comparator for hysteretic mode or triggers fault on a fixed duty PWM signal.But perhaps there's a more appropriate way...?

author: snoop33
author_rank: Contributor
timestamp: January 28, 2023, 04:32:21 pm
content: I've been playing and made it work using hysteretic buck mode.The challenge now is how to make a voltage or PWM controlled attenuator to control it.
Resistive Sheet - Page 1
Forum section: electronics / projects

author: skipjackrc4
author_rank: Regular Contributor
timestamp: May 27, 2014, 10:02:58 pm
content: Does anybody know a source for bulk resistive film? I'm needing a few square inches of material with something around 300 ohm/square.The closest thing I have found to that has been Bare Conductive Paint, which has a surface resistivity of 55 ohm/square at a thickness of 50 microns. In theory, of course, using a thinner coating would work, but I feel like controlling the thickness may be fairly difficult. Does anyone on here have any ideas?

author: stevefwg
author_rank: Newbie
timestamp: August 06, 2014, 02:39:45 pm
content: We do three types of conductive Inks. You can download the Technical Data Sheets here:http://fwgltd.co.uk/index.php/downloadsOur water resistant ink is around 200-240 ohms sq/mil untreated.We have applied the inks to PET film and other substrates. You can see our videos here:https://www.youtube.com/user/RobertMurraySmith/videosIt might be easier to make your own and control the process.Sorry, not trying to blatantly sell anything here. In fact I'll give members of the forum a discount. I am interested in what results you get for different applications.

author: f5r5e5d
author_rank: Frequent Contributor
timestamp: August 06, 2014, 04:43:19 pm
content: if there is some scale below which you don't care then you can make a grid pattern of higher conductivity material to get the particular large scale average sheet resistance

author: woodchips
author_rank: Frequent Contributor
timestamp: August 07, 2014, 11:36:44 am
content: Tried Teledeltos paper? This is paper with a uniform carbon film that was used years ago to plotting field lines, and is apparently still available.
Resistor decade and Murphy - Page 1
Forum section: electronics / projects

author: tszaboo
author_rank: Super Contributor
timestamp: August 17, 2017, 01:34:45 pm
content: Murphy gets you every time.I don't like resistor decades anymore.

author: Rerouter
author_rank: Super Contributor
timestamp: August 17, 2017, 01:54:09 pm
content: better than 1% of value, likely better than 0.5% when you remove all the contact resistance, trace resistance and lead resistance, (not in rel mode) :pYes i see the missing range

author: tszaboo
author_rank: Super Contributor
timestamp: August 17, 2017, 02:00:38 pm
content: Yes, it is better than 1%. I made it with 1% resistors, and the typical is 0.3%, contact resistance is around 0.2 ohm, lead resistrance is 0.1 ohm, quite irrelevant. 0.5mm traces.But that missing range...

author: Kalvin
author_rank: Super Contributor
timestamp: August 17, 2017, 03:31:37 pm
content: It is not missing. You have just soldered 10 x too high value resistors to highest range

author: tszaboo
author_rank: Super Contributor
timestamp: August 17, 2017, 05:05:56 pm
content: Well, it is kinda on the silk-screen.I started the assembly of the first one from the 10M side. An then i switched to the right side. At the 1k-10k range, I was reaching for the last 10 resistor. Wait a minute... there is no space for this...
Resistor Decade Box - Page 1
Forum section: electronics / projects

author: norEL
author_rank: Contributor
timestamp: July 27, 2011, 08:42:28 pm
content: Hello,Dave mentioned in his last live show that there was some request for a simple DIY resistor decade box.I made this one my self last year because I needed a decade box fast. It is sadly in hurry made and I had some trouble with my etching so the finish was not the finest though...But it works perfectly and I have used it several times!The resistors used is: 0207 smt 1W 1% (big enough for my use)Have attached the board layout (Eagle). This board you can copy and paste to build with as many resistor values you like ( 1R, 10R, 1K.... )I had to etch three pcb`s (two with 3 values and one with 1 value, so I have 1R, 10R, 100R, 1k, 10k, 100k and 1M that goes from 0-9 times (goes to 9 999 999R/10M almost with all switches on 9times)) and connect together to make my decade box, because I did not have big enough pcb card at that point.So hope this is some guidance to make your own decade box.Would be nice if you post your`s under this topicQuestions and comments are welcome!Marius
resistor is making me crazy help - Page 1
Forum section: electronics / projects

author: jacobsan
author_rank: Newbie
timestamp: July 30, 2012, 02:56:23 pm
content: someone help me i got these resistors with this bulk of leds i got off the net there is one problem the resistors are giving me some problems. i don't think the people i got them from labeled them right. the resistor has a blue body and i think the bands are yellow , purple ,black, black, and brown i hope i got that right its a bit hard to tell. i was told they were 12v ones or something they came with leds that were from 3 -3.2v.

author: IanB
author_rank: Super Contributor
timestamp: July 30, 2012, 03:00:07 pm
content: Sounds like they are 470 ohm resistors, which will give about 20 mA through a 3 V LED on a 12 V supply.You could measure one with a meter, or test it carefully with an LED at 3 V, 6 V, 9 V and then 12 V and see how the LED runs.

author: 6502nop
author_rank: Regular Contributor
timestamp: July 31, 2012, 01:11:55 am
content: So, what, exactly, is the problem with them? Just the labels?As IanB pointed out, the codes (which are easily Googled) make these:Yellow = 4Violet = 7Black = 0Black = x1Brown = 1% value tolerance- or - a 470 ohm (+/- 4.7) resistor.Using Ohm's law (or an easily Googled LED resistor calculator), we can figure:Vin - Vled = Vres (12Vin - 3Vdrop = 9V across resistor)Vres / Iled = Rled (9V / .02A = 450 ohms)So, those 470 ohm resistors will allow about 19mA, which is just under the max rating. We can confirm this by reversing the math:Iled = Vres / Rled (9V / 470 = 0.019148936A, or 19.14mA).Now, all this is assuming that the LEDs are 3V types. They may be 2V (or, if these are really old stock, 1.8V "teardrop") types. In that case:Vin - Vled = Vres (12V - 2V = 10V)Iled = Vres / Rled (10V / 470 =0.021276596A, or 21.27mA)Which might be pushing it a bit. Personally, I like to limit standard LEDs to 10-15mA - just in case - and haven't had any problems, as newer LEDs are much brighter than those of 20 or 30 years ago. So, where most folks would put a 470R, I'd go for a 510-680R.So, the resistors may be just fine, it may be the LEDs that are the problem. I'd suggest breadboarding an LED and a 1K resistor @12V and actually measure the drops and current with a known (easily calculated) value, and see what you come up with, then adjust the Rled values accordingly.nop

author: Mechatrommer
author_rank: Super Contributor
timestamp: July 31, 2012, 01:09:32 pm
content: buy a multimeter.
Resistor on a post in CRT monitor? - Page 1
Forum section: electronics / projects

author: gmc
author_rank: Regular Contributor
timestamp: May 27, 2024, 03:31:21 pm
content: I'm busy trying to repair a old 12" CRT from the early 80's - Yes, I'm aware of the electrical dangersOne of the components is a 56R resistor which is now reading 100R. Looking at the schematic it's a 56R RN1/4 which from what I can gather is a 0.25W Metal Film Resistor. Resistor looks a bit worse for wear and has overheated.That's all good and easily replaceable. One thing that I've noticed is that there are a few resistors around the HV side that have one leg soldered to a post which I've not seen before.Guessing it's to keep it off the PCB for cooling? But why one leg and why mount it to a post? (Or is the post also some sort of heat sink?)Was this a standard for the CRT's in the 80's?

author: johansen
author_rank: Super Contributor
timestamp: May 27, 2024, 04:38:31 pm
content: Usually 2 posts were used to keep the heat away from the board

author: jonpaul
author_rank: Super Contributor
timestamp: May 27, 2024, 04:56:26 pm
content: post keeps HV arc to PCB surface eg dust.Very common.Use carbon comp resistor rated for the HVJon

author: gmc
author_rank: Regular Contributor
timestamp: May 27, 2024, 06:08:33 pm
content: Thanks for the info. Will source the correct resistor replacement.

author: inse
author_rank: Super Contributor
timestamp: May 28, 2024, 03:57:50 am
content: You can see the windings, this isn’t a carbon composition resistor but a metal film type.

author: CaptDon
author_rank: Super Contributor
timestamp: May 28, 2024, 04:31:22 pm
content: I absolutely agree that it is metal film!!! Carbon Comp replacement is a huge mistake seeing how the metal film burned up. I would also recommend the flameproof version FP which the original resistor probably was. Looks like the O.E.M. expected a possible failure mode of this part and could be part of the reason for the post mounting.
Resistor rating for surge test - Page 1
Forum section: electronics / projects

author: LectroNoob
author_rank: Newbie
timestamp: January 16, 2019, 09:31:12 pm
content: I'm designing a new circuit and I have to use SMD resistors directly on 240Vac. The thing is, this device may undergo surges of 6kV (for a couple of uS) and I don't know which package to use to prevent arcs through or over it. It's a 300K so I don't really worry about power and current. Is there a table somewhere for surge vs package of a resistor?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 16, 2019, 09:40:41 pm
content: Yes, the datasheet gives numbers on that.You may find you'll need an inconvenient number of resistors in series, following the ratings exactly. Pulse ratings (with respect to pulse width) are less often provided, and the parts that provide them are more expensive because they've been tested for that purpose. YMMV.I normally see 3-4 in series, 1206 size, in an application like that. Mind that commercial mains is only tested to 1.5/2.5kV surge, not 6.Resistor ratings aside, note that the layout needs adequate clearance. For example, IEC 60950-1 requires total creepage and clearance such that, in event of a single component failure (i.e., one resistor shorting), the remainder is adequate. This is where 3-4 x 1206s comes from.You may find that it's easier to solve this problem with a few THT resistors, rated for HV or pulse duty. Depends also on what degree of confidence, of standards compliance, and budget, you require.Tim

author: LectroNoob
author_rank: Newbie
timestamp: January 16, 2019, 09:49:44 pm
content: Thank you for your reply.The problem is space for such a high number of resistors.They would have to be placed next to each so the surge would jump to one another without going through the resistor.Maybe THT is the way to go on that one.Clearance has been taken care off.

author: spec
author_rank: Frequent Contributor
timestamp: January 16, 2019, 09:50:01 pm
content: Hi LectroNoobA transient voltage suppressor (TVS) may solve your problem and protect the electronics in general: look at the bi directional TVS:https://www.littelfuse.com/~/media/electronics/datasheets/tvs_diodes/littelfuse_tvs_diode_smcj_datasheet.pdf.pdf

author: Benjawran
author_rank: Newbie
timestamp: January 17, 2019, 07:21:22 am
content: It's the information I'm looking for as well.

author: PartialDischarge
author_rank: Super Contributor
timestamp: January 17, 2019, 07:32:35 am
content: Try one unit of the chv2512, I bet they can repeatedly handle 6kv for a few us, but you will have to test. The board will need a cut and probably a bit of coating though.https://www.mouser.es/datasheet/2/54/HV-777595.pdfOtherwise use a Vishay VR25, it is rated for that pulse, cheap and smallhttps://www.mouser.es/datasheet/2/427/vr25vr37vr68-837991.pdf
Resistor string DAC as audio volume pot? - Page 1
Forum section: electronics / projects

author: technix
author_rank: Super Contributor
timestamp: July 15, 2016, 06:29:31 pm
content: I went back to my TLC5615 DAC datasheet yesterday and it said that its reference voltage have a 30kHz bandwidth. Somewhat higher than audio range already.So how good is this resistor string DAC as audio volume pots? Those cost about the same (if not lower) as MCP41010s but offers better tempco and 4x resolution.

author: singapol
author_rank: Frequent Contributor
timestamp: July 15, 2016, 07:00:42 pm
content: Maybe this one if you are serious? PGA2311https://www.yuan-jing.com/pga2311-lcd-remote-volume-amp-channel-selector-boardwww.ti.com/cn/lit/gpn/pga2311

author: technix
author_rank: Super Contributor
timestamp: July 15, 2016, 07:08:14 pm
content: Quote from: singapol on July 15, 2016, 07:00:42 pmI'm not really okay with its price... 2x TLC5615 costs less than half of that PGA2311.

author: Kleinstein
author_rank: Super Contributor
timestamp: July 15, 2016, 07:36:20 pm
content: One problem with the TLC5615 is, that the internal amplifier is not really low noise this limits the S/N ratio. Like with the digi-pots the voltage range is 5 V only. So with the digi - pot one could use a better amplifier and this way get better S/N. S/N might be a real problem here, as the signal here is at maximum loudness, so S/N in a low volume setting can be rather low. The better temperature specs are not relevant, as nobody can hear it. The temperature of the speaker usually has a much larger effect. Higher resolution helps a little, but the range for adjustment is still relatively small, so one might need to cascade two, or add a few coarse steps. If done right, this also reduces the problem with noise.The PGA2311 gives much better performance and allows a much wider range. So it replaces more than the TLC5615 and at a way better performance.There should be other, cheaper audio level chips, cheaper, not as good, but still higher performance than the tlc5615. It's just that a log scale is much better for audio.
Resistors in a led chaser strip - Page 1
Forum section: electronics / projects

author: Unknown
author_rank: Unknown
timestamp: November 12, 2014, 04:42:13 pm
content: I'm designing a led chaser with 64 leds with pwm capability and for budget constraint i have to use the 74hc595. The leds are blue and have a typical Vf of 3.1V and a max of 3.8V. The power supply of the leds is 3.3V. Is in your opinion ok to omit the resistor and connect the leds directly to the 595? Keeping im mind that the leds will be pulsed. I don't think there will be any problem with the leds but i don't know how the 595 will behave.

author: Tandy
author_rank: Frequent Contributor
timestamp: November 12, 2014, 04:55:02 pm
content: Am I understanding you correctly, you are trying to run LEDs with a minimum 3.1V requirement from a 3V supply?EDIT: I see you edited your post from 3V to 3.3V, in that case it should be OK.

author: klr5205
author_rank: Regular Contributor
timestamp: November 12, 2014, 05:02:55 pm
content: Cheap led keychains simply short a white led across a coin cell and count on the voltage being just right to not burn it out, so it might work to an extent.Hook your supply to the exact led you plan on using and measure the current (if any) that flows. Then you can make a judgement whether you can get away without resistors.

author: Unknown
author_rank: Unknown
timestamp: November 12, 2014, 05:06:23 pm
content: Quote from: Tandy on November 12, 2014, 04:55:02 pmSorry, the supply is 3.3v and 3.1 is the typical Vf, on the current/vf graph it goes down to 2.8V . Post edited.
Resource: Made in China with Love - Chinese-designed awesome chips - Page 1
Forum section: electronics / projects

author: technix
author_rank: Super Contributor
timestamp: August 22, 2015, 08:43:32 pm
content: Here it is:https://github.com/xcvista/micwl/Made in China is always cheaper but is it really worse in quality? Maybe not, especially for those semiconductor components.Everyone is welcomed to contribute - just send me a pull request.
Resource or Guide: 'Certifications for selling consumer electronics worldwide?' - Page 1
Forum section: electronics / projects

author: Chendy
author_rank: Contributor
timestamp: September 20, 2019, 11:12:10 am
content: Hi,I'm in the process of bring a 110 - 240VAC product to market that contains an 'intentional emitter'. I want to learn more about what certifications are needed, and a bit about them. I am using a certifications consultant, but want to study up.focus is on European and North American markets, but also some other major global markets. Especially interested when they deviate from what needs to be done for EU & USA..Thinking terms like CE, FCC, CSA, European RED directive. Ideally stuff covering lithium batteries.As well as mandated things like perhaps CE, what is practically needed or potentially beneficial to have, such as UL, VDE(?). As I understand retailers will insist on UL + ??.I have found this book, which I may buy and read:https://emcfastpass.com/cert-ebook/Has anybody read it?Can anybody recommend any other or better resources?All the best

author: Benta
author_rank: Super Contributor
timestamp: September 20, 2019, 03:45:28 pm
content: I'm no expert on UL, but concerning the EU certifications, you need a layered top-down approach.At the top level, there's CE, which is the manufacturer/importer's legal obligation. It's is a signed certificate of conformance that the equipment fulfills the norms needed/specified.Below that, you have the directives, like EMC, LVD, RED etc., these are totally equipment-type relatedAnd below that, you have the harmonized standards, usually with an ENxxxxx number.VDE is no longer relevant, it's been replaced by the EU-wide regulations.
Resources for designing a sensored BLDC ESC? - Page 1
Forum section: electronics / projects

author: trilerian
author_rank: Regular Contributor
timestamp: December 20, 2024, 05:44:59 am
content: I think it is about that time... I am going to start researching how to design and build a sensored BLDC ESC. I've been tinkering around on other stuff for the last couple of years now, trying to gain the experience to start this project.I would like to use N channel mosfets on the high and the low side, I know P channel are generally used on the high side, but I would like to go with N channel. Also this should be able to handle 50-60A. I need to have 2 different voltages that the motors can run at, 7.4V and 3.7V, the idea is to provide as close to a constant voltage as I can, as this device will be for motor testing. But in the end, it is an ESC...I would appreciate any resources to read and study up on.Thanks in advance!