hybridfree/eevblog-posts huggingface dataset:
Ferrite Beads - Page 1
Forum section: electronics / projects

author: TeraHz
author_rank: Contributor
timestamp: November 09, 2010, 03:55:20 am
content: Hello,I'm working with a ENC28J60 IC (Ethernet controller) that requires a ferrite bead "rated for at least 80mA" for EMI reduction (from the datasheet). I've been using a Murata SMD (Mouser: 81-BLM21BB600SH1D ) with the following specs:Impedance: 60 OhmsTolerance: 25 %Maximum DC Current: 200 mAmpsMaximum DC Resistance: 0.2 OhmsTest Frequency: 100 MHzI'd like to change it to a through-hole part, however all through hole parts are in the multiple A and mOhm range.Since I'm not sure how the maximum DC current and resistance are related to the effectiveness of the filter I wanted to ask here if something like the Panasonic EXC-ELS ferrite (Mouser: 667-EXC-ELSA35V) will be suitable replacement. Specs:Impedance: 50 OhmsMaximum DC Current: 7 AmpsMaximum DC Resistance: 10 m OhmsTest Frequency: 100 MHzFrom my reading it seems like the Impedance and size of the ferrite are what matter for the filter, but the reference design in the datasheet doesn't mention anything about that.ThanksEDIT: Ooops, that was for the beginners forum... sorry

author: qno
author_rank: Frequent Contributor
timestamp: November 09, 2010, 07:08:13 pm
content: Looks ok to me.Slightly lower impedance at 100 MHz.

author: TeraHz
author_rank: Contributor
timestamp: November 09, 2010, 08:29:21 pm
content: Thanks qno. There are also 80Ohm versions of it, will that be the better choice?...Since this is the projects forum I'll make the topic a bit more relevant. The project is a dual avr board with RTC, PH circuit, Ethernet circuit and port expander for LCD. It is going to be a Reef tank controller. I will post the schematic when I get home. Project is open source.http://code.google.com/p/hydra-reef/

author: Chris_R
author_rank: Contributor
timestamp: November 12, 2010, 12:00:14 pm
content: If you're just using it for fun instead of an actual project then you can just replace the ferrite with a piece of wire, which I have before with the ENC28J60. Obviously you shouldn't do this in a proper design as it won't conform to specs, but for non-commercial it's fine.

author: TeraHz
author_rank: Contributor
timestamp: November 12, 2010, 04:42:00 pm
content: Well it is mainly for fun, but also for others to benefit, so the goal is to be as good as we can make itSeems like the 50 Ohm ferrite will do the job.Thanks

author: cybergibbons
author_rank: Frequent Contributor
timestamp: November 12, 2010, 05:36:31 pm
content: Quote from: TeraHz on November 09, 2010, 03:55:20 amWhat's the drive for switching to through hole?

author: TeraHz
author_rank: Contributor
timestamp: November 12, 2010, 05:44:32 pm
content: This is a reef controller (aquarium etc) and we want to make it through hole so that it is accessible for more people. And that ferrite is tiiiny for people who have a radio shack solder
Ferrite core question - Page 1
Forum section: electronics / projects

author: Chris Wilson
author_rank: Super Contributor
timestamp: September 22, 2015, 09:39:15 am
content: Is this core:http://uk.farnell.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=15001&langId=44&urlRequestType=Base&partNumber=3056417&storeId=10151supposed to be used as is, or mated to a second one to form a split but enclosed core around any winding?That's to say, two placed legs to legs to form a square with a vertical central post around which the winding is placed? I see they do a bobbin, but I can't make out if the cores should be used singly or as a pair. Thanks.

author: Phoenix
author_rank: Frequent Contributor
timestamp: September 22, 2015, 09:57:11 am
content: 2 cores facing each other. Here are some assembled versionshttp://i01.i.aliimg.com/photo/v2/485733047/ETD49_20_3_Welding_welder_transformer_used.jpghttp://www.3dcontentcentral.com/ShowModels/ContentCentral/ETD49_NO_AIRGAP/ETD49_NO_AIRGAP.JPG(do a google image search for ETD49 for more examples)

author: Chris Wilson
author_rank: Super Contributor
timestamp: September 22, 2015, 10:11:42 am
content: OK, thanks, have ordered the other half and a bobbin and clips, I thought it seemed odd.....Appreciated!

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 22, 2015, 11:42:01 am
content: Datasheet says "CORE HALVES, blah blah, order number ETD49/25/16-3C90", which is the part number you ordered. So they should be single pieces.Tim

author: Chris Wilson
author_rank: Super Contributor
timestamp: September 22, 2015, 12:24:40 pm
content: Yes, I bought 2 halves, but need to make 2 transformers, so have ordered 2 more, plus 2 bobbins and the clips to hold the halves together without Heath Robinson stuffThanks!
Ferrite Core Transformer - Page 1
Forum section: electronics / projects

author: whatty
author_rank: Contributor
timestamp: February 16, 2023, 06:25:23 am
content: HiI am an Electronic enthusiast i am working on a project where i needed to design a SMPS (ac to dc) using FLYBACK topology. i understood how the flyback converter works all those stuff but i couldn't find a proper design procedure for the ferrite core transformer for the converter please can you help how i can design a ferrite core transformer by sharing any document or links.Thanks in advance

author: moffy
author_rank: Super Contributor
timestamp: February 16, 2023, 06:54:04 am
content: A flyback converter works by storing energy in the primary side inductance E = (Lp*Ip*Ip)/2 where Lp = Primary inductance and Ip = Peak Primary current and E = Energy in joules. The power transfer is E*f watts where f = the frequency of the primary pulses. You choose the turns ratio based somewhat on voltage in and out but that is a bit flexible with a flyback. Have you just tried Googling the term "How to design a flyback transformer"?

author: whatty
author_rank: Contributor
timestamp: February 16, 2023, 07:08:34 am
content: Hi thanks for the reply please can you share any detailed documents about this

author: armandine2
author_rank: Frequent Contributor
timestamp: February 16, 2023, 08:46:01 am
content: There is a pdf of Keith Billings I've seen which might be useful - not my area of expertise

author: Zero999
author_rank: Super Contributor
timestamp: February 16, 2023, 10:27:33 am
content: https://en.wikipedia.org/wiki/Flyback_converter?useskin=vectorhttps://media.monolithicpower.com/mps_cms_document/2/0/2021-aip-how-to-design-a-flyback-converter-in-seven-steps_r1.0.pdfhttps://www.ti.com/seclit/ml/slup261/slup261.pdf
Ferrite cores found salvaged from cables. - Page 1
Forum section: electronics / projects

author: firewalker
author_rank: Super Contributor
timestamp: August 11, 2015, 06:49:36 am
content: Are the ferrite core used as EMI filters suitable for inductors in DC-DC converter. What is the composition usually used?Alexander.

author: Kleinstein
author_rank: Super Contributor
timestamp: August 11, 2015, 10:24:21 am
content: The EMI filter inductors usually are high loss materia - so not really suited for an efficient converter. It will work, but lossed are high.An exception may be current compensated inductors - they may be just high permeability without extra going for high loss. So they might be ok in a forward DC/DC converter.

author: firewalker
author_rank: Super Contributor
timestamp: August 11, 2015, 10:26:24 am
content: Thanks you.Alexander.

author: MagicSmoker
author_rank: Super Contributor
timestamp: August 11, 2015, 10:39:41 am
content: Ferrite cores for EMI suppression are usually made of the same material as "power" ferrites - Manganese-Zinc - so they could be used in a switchmode power supply. They really start looking lossy around 1MHz, so as long as you kept the switching frequency below, say, 100kHz you shouldn't have any problem with core loss.They don't have an air gap (even the snap-on ones have very little gap when closed) so don't try to use them in applications where any DC bias is present (ie - chokes or flyback transformers). They also tend to have a very large core area to window area ratio, which helps with losses but hinders power transfer capacity (because you can't wind too many turns).

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 11, 2015, 09:40:47 pm
content: Eh, MnZn and NiZn are both used. Depends. NiZn "wideband" I would say are the most common formulations (e.g., Fair-Rite #43, 44).The loss isn't a problem at most power switching frequencies (< 500kHz).What you do have to beware of is magnetization. They saturate readily from DC, so they are only suitable in AC transformers and full wave converters. You won't have good performance (or any at all), even from a quite oversized core, in any method that requires DC (half wave forward converter, flyback, etc.).Tim
Ferrite inductor or Coil Inductor for Boost Converter - Page 1
Forum section: electronics / projects

author: SwissEngineer
author_rank: Contributor
timestamp: February 04, 2016, 09:48:11 am
content: Hello Everyone,I am designing a board and I need to choose the right inductor for my boost converter (TPS61220). The Vin is 3,6V and Vout 5,2V.But my question is: Can I use a Ferrite bead as an inductor (http://www.digikey.ch/product-detail/fr/MLZ1608N4R7LTD25/445-17071-1-ND/4869871), I can't see the difference between a 4,7uH ferrite and a 4,7uH coil...Thanks for the help

author: krivx
author_rank: Frequent Contributor
timestamp: February 04, 2016, 09:57:43 am
content: How much current are you looking for? It looks like that ferrite will saturate at only 80mA.

author: SwissEngineer
author_rank: Contributor
timestamp: February 04, 2016, 10:09:44 am
content: True... But why is the saturation current lower than the nominal? I wanted the maximum of the boost, so 400mA.

author: RobK_NL
author_rank: Frequent Contributor
timestamp: February 04, 2016, 10:21:55 am
content: Quote from: SwissEngineer on February 04, 2016, 09:48:11 amWell, I would suggest to look at the graph for "INDUCTANCE VS. DC BIAS" for that ferrite and then compare it to the graph for this coil:http://www.digikey.ch/product-detail/fr/CIG22B4R7MNE/1276-6218-1-ND/3972136Still don't see it?

author: SwissEngineer
author_rank: Contributor
timestamp: February 04, 2016, 10:26:30 am
content: Okay just found the awnser.A Ferrite will decrease the inductance as the current increases, so when the current is nominal, the inductance is null.On the opposite, the Coil will keep the inductance until the saturation current. (See pictures below)Conclusion (correct me if I'm wrong) : I can't use a ferrite instead of a coil with a boost converterPS : I saw the graph before your replybut thanks!!

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 05, 2016, 02:57:08 am
content: Ferrite beads are sold by small-signal impedance at some frequency, at zero DC. (I'm amazed those TDK parts are even sold by inductance!)They are not intended to function under DC bias (despite their typically generous current ratings, and frequent use in power supply rails).Inductors are sold by inductance and DC bias. (Conversely, they don't usually specify impedance at frequency, which makes it difficult to estimate efficiency.)Inductors are made to store energy, ferrite beads are made to crudely filter (or dampen) small signal pins.Shop accordinglyTim
Ferrites suitable for RF and balun - Page 1
Forum section: electronics / projects

author: mehdi
author_rank: Regular Contributor
timestamp: December 03, 2015, 05:58:24 pm
content: HiHow can I determine if a particular ferrite is suitable for RF work (like baluns)?In my country, finding good RF parts is difficult and they are not sold with part numbers , so we want to find a way to check if they're good for our RF works.Thanks

author: w2aew
author_rank: Super Contributor
timestamp: December 03, 2015, 09:47:16 pm
content: Quote from: mehdi on December 03, 2015, 05:58:24 pmWithout any knowledge of the core material, ferrite or powdered iron, or knowledge of the type/mix, the best thing you can do is wind some devices (inductors, transformers, baluns, etc.) and test the performance in the intended application. You can make an estimate of the material's suitability by making an inductor with the material and testing it.I did make a video on the basics of ferrites, although it probably won't answer your question...
FET driven remote ignition - Page 1
Forum section: electronics / projects

author: twjdeboer
author_rank: Contributor
timestamp: October 23, 2013, 08:47:27 am
content: Hi everybody,I'm currently in the process of building a remote igniter for a small project in my student society.I wanted to use an old doorbell in conjunction with a FET, for handling the high power and a 3,3 Ohm resistor.All the pieces work well. When I press the doorbell, my FET goes to '0' Ohms, and I measure the 4,7 volts of my 3 AA batteries. I can ignite the resistor with the batteries (I measured 8 Amps when shorted).The thing is: when I use my FET circuit, the output Current (again, shorted with the DMM) is only 400 mA. It was suggested to me that this was because of internal resistances in the batteries and fet circuit, but the math just doesn't check out for me.I wrote this little matlab script to find out my maximum output current and optimal value for the resistor. Don't know if I've done something wrong.Code:clear allclcclose allUb = 5 ;Rth = [1:0.01:10] ;Rl = [0:0.1:20] ;for j = 1 : length(Rth)for i = 1 : length(Rl)Ur = Rl(i) / (Rl(i) + Rth(j)) * Ub ;I = Ur / Rl(i) ;P(i) = Rl(i) * I^2 ;endPmax(j) = max(P) ;endRth_max = Rth(find(Pmax > 3, 1, 'last'));for i = 1 : length(Rl)Ur = Rl(i) / (Rl(i) + Rth_max) * Ub ;I = Ur / Rl(i) ;P(i) = Rl(i) * I^2 ;endfigureplot(Rl,P)I looked for the value where my maximum output power was >3 watts. I need a Rthevenin of around 2 Ohms, which I cannot measure with my cheapie multimeter. I get this plot for power vs. Heater Resistance.I'm usinghttp://www.irf.com/product-info/datasheets/data/auirf540z.pdfFET. This is my first encounter with FETs so far, so maybe I get the concept wrong, but it kinda works already.

author: twjdeboer
author_rank: Contributor
timestamp: October 23, 2013, 09:28:57 am
content: I'll draw up a schematic when I have the time. I'm trying to ignite a paper temple which is our symbol. Nothing maliciousI'm using Duracell AA batteries, fresh out of the pack. Should I get a different FET maybe?

author: twjdeboer
author_rank: Contributor
timestamp: October 24, 2013, 09:07:58 am
content: Thanks for helping me out. I had a brainwave and remembered the Li-ion batteries that came with my cordless drill.I decided to create it anew entirely and it now kinda works. It's still a bit hit or miss, but good enough. Thanks for helping me.I hope I didn't end up on some NSA watchlist...

author: peter.mitchell
author_rank: Super Contributor
timestamp: October 24, 2013, 09:53:43 am
content: Quote from: twjdeboer on October 24, 2013, 09:07:58 amyou were long ago.
FET gate drive transformer leakage figure....minimum is stated, not max - Page 1
Forum section: electronics / projects

author: ocset
author_rank: Super Contributor
timestamp: November 26, 2017, 01:57:49 pm
content: Hello,Do you know why this gate drive transformer family (HM42) states the minimum leakage inductance instead of the maximum?......as you know, the minimum figure is not useful....customers need the maximum, so as to calculate the delay in turning on the FET...http://www.farnell.com/datasheets/2333110.pdf?_ga=2.244164165.1106301863.1511695680-287702491.1506211291If you are also stumped, then please may you tell of a different family of OTS FET pulse transformer drivers?, which do state max leakage...F(sw) is 100khz so we need low leakage.
FFC (flat flex cable) in audio and powersupply - Page 1
Forum section: electronics / projects

author: strawberry
author_rank: Super Contributor
timestamp: September 30, 2017, 03:47:15 pm
content: I would like to use them in my design, audio, control signal, and power..

author: chris_leyson
author_rank: Super Contributor
timestamp: September 30, 2017, 06:07:13 pm
content: Hi, I've used 0.5mm pitch flat flex for carrying Gige ethernet without any problems and FFC connectors are used to interface many OEM Gige cameras for example. Crosstalk wasn't a problem and in fact my crosstalk measurements at 125MHz were limited by the home brewed test jig and not the flat flex.However, Gige ethernet signals are balanced and have 100 ohm differential terminations so this will reduce crosstalk. If you are going to use flat flex for low level audio signals just make sure you keep the terminating impedances low, say a few k ohms rather than M ohms.You might also nedd to consider using differential signals but a lot will depend on how well the enclosure acts as a screen and any stray magnetic fields from transformers or switched mode supplies for example.0.5mm pitch flat flex is a bit tricky to use or assemble in confined spaces and I've broken a few connectors from rough handling so I always order a few extra connectors so I can replace the locking strips if I break one. 1.0mm pitch is easier to handle and work with and has lower resistance but check the data sheets for current ratings.In principle I don't see why you can't use flat flex for audio but watch out for pickup from stray fields.

author: SeanB
author_rank: Super Contributor
timestamp: October 01, 2017, 04:58:56 pm
content: You can still get twisted pair flat cable, and it is reasonably immune to interference, though the regular one does quite well simply by using alternate wires as a ground.
FFC connection to PCB - Page 1
Forum section: electronics / projects

author: shadewind
author_rank: Frequent Contributor
timestamp: September 14, 2011, 03:16:09 pm
content: I know there are ZIF connectors which can be mounted on PCBs to interface with FFC cables but for some FFC styles I can't seem to find any connectors. How do you interface with these? Can you solder them to the board? Press them against pads on the board? What is the best way to do this?This is an example, an OLED display with 0.7 mm FFC pitch as far as I can tell:http://www.farnell.com/datasheets/56397.pdf

author: daedalus
author_rank: Regular Contributor
timestamp: October 04, 2011, 10:57:01 pm
content: On rigid displays such as lcds you come across designs using a type of rubber strip that is conductive only from top to bottom, not left to right (think a stack of slices of conductive and insulate material). This rubber is placed between a terminal strip on the screen, and similar pads on the pcb, and light pressure is applied. Where the slices make contact with a conductor on the display, and a pad, current can flow, but the adjacent pins are still electrically isolated from each other.I have no idea what the material is called I'm afraid, only came across the construction method stripping down some scales recently.Maybe something similar is possible with this display? It appears there are two holes in the FFC for attachment / clamping.

author: daedalus
author_rank: Regular Contributor
timestamp: October 04, 2011, 11:02:26 pm
content: Actually just did a quick check, and this stuff looks far more promising, it works the same as the rubber, but in a thin adhesive tape.http://solutions.3m.com/wps/portal/3M/en_US/AdhesivesForElectronics/Home/Products/SpecialtyTape/AnisotropicConductiveFilms/

author: Joshua
author_rank: Regular Contributor
timestamp: October 05, 2011, 02:08:44 am
content: Quote from: daedalus on October 04, 2011, 10:57:01 pmPeople commonly refer to these as 'zebra strips'. I think flukes official term for them(for use in their meters) is 'elastomer'

author: IanB
author_rank: Super Contributor
timestamp: October 05, 2011, 02:42:20 am
content: Quote from: Joshua on October 05, 2011, 02:08:44 amElastomer is just a technical word for an elastic compound like rubber. The term you are looking for is 'elastomeric connector'.

author: Joshua
author_rank: Regular Contributor
timestamp: October 05, 2011, 04:09:09 am
content: Quote from: IanB on October 05, 2011, 02:42:20 amAaahh that's what it is! I thought it sounded a bit different...
FFC connector non ZIF (snap in) - Page 1
Forum section: electronics / projects

author: Nikos A.
author_rank: Regular Contributor
timestamp: June 23, 2021, 08:55:52 pm
content: Hi, I am looking for a 10 pin FFC connector non ZIF and I am straggling to find one. I have searched in Mouser and Digikey without luck. Probably I do not apply the proper filtersI found this from JST but this is not available nor in Mouser or Digikeyhttps://www.jst-mfg.com/product/detail_e.php?series=554I have also found this type of connector in nrf52840 dev kit (NFC connector)Does anyone know how to search this type of connectors? I design a small PCB (3 x 1.5cm) board and I am looking for a very small connector to provide programming interface to my board. I would like you suggestions for alternative solutions as well

author: ajb
author_rank: Super Contributor
timestamp: June 24, 2021, 06:00:43 am
content: Development boards like this usually have published schematics, and in this case they show that part as a Cabcon 5141-05RZDNWR01. It looks like that's discontinued, but google brings up this, which recommends an alternate:https://devzone.nordicsemi.com/f/nordic-q-a/35070/nfc-connectorI'm not sure I'd want an FFC connector for a programming interface, since they're so fiddly. Maybe if I needed to bring out a bunch of signals for development and was really space constrained and wouldn't have to plug/unplug it often (FFC connectors are often only rated for a couple dozen mating cycles!). But for <10 signals I'd probably prefer either a less fiddly connector that will be easier to mate and unmate, or pads I can solder wires to for development or use with a little pogo pin adapter for programming. That NFC connector is five positions, and except for height doesn't look much smaller than a six position 50mil header. Lots of people like the Tag-Connect cables, so that's an option as well.

author: Nikos A.
author_rank: Regular Contributor
timestamp: June 24, 2021, 09:59:14 am
content: Hi ajb and thank you for you response,Quote from: ajb on June 24, 2021, 06:00:43 amI totally agree with you!! In the previous prototyping version, I included an FFC ZIF connector and I end ti up with a broken actuator after some cycles. That's the reason I want to avoid FFC connectors with actuator this time.Quote from: ajb on June 24, 2021, 06:00:43 amOk, I didn't even know about this type of connector. It looks promising for my application and they provide accessories as well to combine it with my J-Link debugger. Thanks for your suggestion!!Quote from: ajb on June 24, 2021, 06:00:43 amDo you something in mind? or you are just referred to the Tag-connect cable?
FFC PCB connector, top or bottom connections? - Page 1
Forum section: electronics / projects

author: wilfred
author_rank: Super Contributor
timestamp: June 09, 2016, 07:07:49 am
content: /.

author: DTJ
author_rank: Super Contributor
timestamp: June 09, 2016, 01:04:56 pm
content: As I understand it the top / bottom option is simply to allow for different board orientations.The ends are finished the same regardless of draw'ed or not. I prefer the drawer style as you need less force to install the cable. I always worry about slipping and putting a fold or kink in flat cables when pressing into non drawer types.

author: chris_leyson
author_rank: Super Contributor
timestamp: June 09, 2016, 02:47:48 pm
content: Never heard horizontal mount FFC connectors called drawer type before. There are two FFC cable types, type 1 with the contacts on the same side and type 2 with the contacts on oposite sides. You have to pick the connector and cable type so as to make the cable routing easy, you don't want to put multiple 45 degree or 90 degree bends just to get the contact orientation correct.Omron make FFC connectors with the contacts on both sides, which I thought was neat, but then again maybe not so, if you turn you FFC cable around 180 degrees the magic smoke might escape.

author: DTJ
author_rank: Super Contributor
timestamp: June 10, 2016, 12:50:24 am
content: The drawer type have a section that slides back allowing the cable to be inserted with close to zero force. The drawer is then pushed in and the cable is locked in place.
FFT or discrete bandpass filters - Page 1
Forum section: electronics / projects

author: Caleb_P
author_rank: Newbie
timestamp: June 17, 2013, 09:18:45 pm
content: I am adding a music visualizer to my current project and need some advice. The circuit has a MCU, LED display with driving hardware and a microphone with an opamp. I want to get the magnitude of a few frequencies and display corresponding animations on the LEDs. I can do an FFT on the MCU but I'm trying to maximize sleep time for power efficiency reasons. Running an FFT and doing lots of ADC measurements will drastically reduce battery life. My other option is to select 4 frequencies and build 4 second order pass band filters. I can then rectify these 4 AC frequencies using a diode and have a Resistor and Capacitor in parallel. This would give me an approximate magnitude reading for each frequency.Do you think it is worth the effort and extra cost to add the analogue front end or just take the hit on battery life? I plan for my project to be produced in small quantities (100-1000) but I am still concerned about cost. Any advice would be appreciated.

author: nctnico
author_rank: Super Contributor
timestamp: June 17, 2013, 10:52:27 pm
content: You can implement 4 IIR filters (elliptic 2nd or 4th order). These take little processing power if your MCU has a hardware multiplier.

author: Caleb_P
author_rank: Newbie
timestamp: June 17, 2013, 11:06:10 pm
content: Thanks nctnico. I will look into the efficiency of that compared to the other two options.
FGG676 BGA On 6 Layer PCB with Standard Fabrication Specifications Possible? - Page 1
Forum section: electronics / projects

author: petersanch
author_rank: Regular Contributor
timestamp: July 31, 2021, 03:12:57 am
content: Has any body had success routing a 676 pad 1 mm pitch BGA part using the standard JLCPCB fabrication specifications? This is for a Xilinx FPGA with the FGG676 footprint.I plan to have one layer for ground, one for power rails, and 4 layers for signals.

author: Boscoe
author_rank: Frequent Contributor
timestamp: July 31, 2021, 08:23:21 am
content: I’ve never completed this specific case but 1mm pitch is very doable as long as you can fit vias in between the pads. The layer count will only restrict how many pins you can fan out.

author: petersanch
author_rank: Regular Contributor
timestamp: July 31, 2021, 09:40:26 am
content: Quote from: Boscoe on July 31, 2021, 08:23:21 amThanks. I need to use most of the pins from the FPGA but I wonder if that is too many traces to fan out on 6 layers.

author: mon2
author_rank: Frequent Contributor
timestamp: July 31, 2021, 11:59:59 am
content: I think you will be facing "via-in-pad" process for your PCB layout. This process is not supported by JLCPCB. Many discounted PCB shops just cannot handle the same. We had to use this in our layout for our ICE40 WLCSP device (16 balls in 1.4*1.4mm) design.Here is a shop we have used and met in HK numerous times - not JLCPCB pricing but they get the job done for our complex designs at fair prices:Nicole is a pro in the PCB industry.QuoteYou can also consider ChinaFastPrint but know that after they setup their USA office a few years ago, we could build the bare PCB for a lower cost with North American shops. Since then, we have received contact from former CFP employees in Asia who will broker the job to their plant at "Chinese" prices. CFP has great capability and we have used them for 50++ projects to date but halted the relationship due to the inflated USA branch pricing. From last chats, CFP can support 3mil trace/space and fairly confident they can also handle via-in-pad process.

author: filssavi
author_rank: Frequent Contributor
timestamp: July 31, 2021, 12:19:54 pm
content: The first FPGA I have done a PCB for is a Spartan 7 ftgb196 on a standard 4 layer board, there was absolutely no issues…You might need more than 6 layers depending on the constrains of your design (how many voltage domains, signal integrity requirements, track width/spacing etc.But a low cost Chinese manufacturer like JLC or PCBway should be capable of handling it fine
Fiber optic FM modulation - Page 1
Forum section: electronics / projects

author: Bibiricat
author_rank: Contributor
timestamp: October 29, 2013, 10:25:59 am
content: Hello.I find myself asking you for help with one of my problems.What i need to build is an audio transmitter that will transmit via fiber optic a frequency modulated signal to a receiver that should be able to rebuild the signal.The problems i am having is that i can't find a schematic that will generate a 100kHz (or more) sine wave and could modulate that signals frequency based on a audio (max 20kHz) signal, and then transmit that through a fiber optic cable. I would also need a receiver that would take the fiber optic signal and recompose the audio signal.Any help would be greatly appreciated.

author: Zero999
author_rank: Super Contributor
timestamp: October 29, 2013, 12:09:19 pm
content: Just to be picky, this isn't optical FM because that would involve modulating the frequency of light which is possible with a tunable laser.You need a 100kHz VCO but the problem is getting sufficient modulation at that frequency sinewave isn't easy. You could build a triangle VCO and use a wave shaper to get a sine output. Another option is a beat frequency oscillator. Build two RF oscillators, one with a fixed frequency of 1MHz and a VCO with a centre frequency of 1.1MHz and a range and put them through a mixer. The output from the mixer will be 100kHz with no signal and you'll only need to change the frequency of the VCO by +/-20kHz to give a sweep of 80kHz to 120kHz.
fiber optic to BNC diode adapter thing? - Page 1
Forum section: electronics / projects

author: coppercone2
author_rank: Super Contributor
timestamp: February 21, 2021, 10:12:03 pm
content: So I have a amplifier with a BNC that I can hook up a diode to with some aligator clips and it works great for amplifying itBut I was wondering, is there some kind of sensor that you can buy that is just a diode with the mechanical reseptical directly connected to a BNC connector so you can plug a fiber line into it? I like the amplifier.Or a mechanical drawing to put a photodiode into that would allow for a standard fiber cable (what is this?) to connect to the amplifier. Or some kind of collet/screw thing that would allow me to connect different kinds of standard fiber cables to it? Can this be made? Perhaps optical epoxy + lapping (I can do a small amount of this) to pot the diode. I have a few IR? diodes that have like blue windows and are gold plated.I see plenty with an amplifier attached but I just want the diode, the amplifier I have can do the rest. The amplifier can do something like 60MHz, so I guess it could be coupled to some kind of medium speed fiber system? I have no idea at all about fiber optic parts specifics. I was imagining doing something with epoxy brass and a BNC connector, but this does exist already ? Does this need some kind of lens or is the little lens on the diode enough?this is what i have to work with for the diodehttps://www.ttelectronics.com/TTElectronics/media/ProductFiles/Optoelectronics/Datasheets/OP913.pdfand another one that has 80pF capacitanceAre they any good for this sort of thing?ok, some of these fit into a F connector, so you can put one inside of a f connector if it turns out the body polarity is correct then use a F to BNC adapter to make a cheap fiber hook upI think I will try a FC connector, they are cheaper then I thought. I decided doing anything with a F connector is fail

author: jmelson
author_rank: Super Contributor
timestamp: February 23, 2021, 02:14:37 am
content: Quote from: coppercone2 on February 21, 2021, 10:12:03 pmWhen reverse biased by even a few volts, the capacitance drops dramatically.

author: coppercone2
author_rank: Super Contributor
timestamp: February 23, 2021, 02:50:01 am
content: yeah i see the ones for sale have a power pin, so its not always amplified but its just a bias sometimes with those modules?
Fiber Transmitter and Receivers - Page 1
Forum section: electronics / projects

author: tchiwam
author_rank: Regular Contributor
timestamp: August 08, 2022, 04:51:08 pm
content: Hello all,Having another weird project here, I want to move the PPS and REF clock to the receivers in a moving part while keeping the GPS/Clocks etc in a nice room that is not moving.I am looking into fiber drivers, mostly Broadcom stuff right now, and I am wondering if one of you has a good suggestion, I'd want <1ns rise time on a 1Hz clock. I did find some DC to ~100MBaud pairs..anyone having an idea where I can find the highest From DC data bandwidth pair of Receivers and Transmitters ?

author: tchiwam
author_rank: Regular Contributor
timestamp: August 08, 2022, 05:58:38 pm
content: This is my favourtie so far : AFBR-1629Z
fiducials under through hole components? - Page 1
Forum section: electronics / projects

author: incf
author_rank: Frequent Contributor
timestamp: April 24, 2025, 02:44:10 pm
content: Do you ever place SMT fiducials under through hole components? Is there any reason not to?

author: Martinn
author_rank: Frequent Contributor
timestamp: April 24, 2025, 04:50:42 pm
content: In circuit testers/flying probe or AOI needing the fiducials?

author: thm_w
author_rank: Super Contributor
timestamp: April 24, 2025, 11:31:14 pm
content: https://www.eevblog.com/forum/manufacture/fiducials-under-chips/
Field-programmable analog arrays / Anadigm dpASP - Page 1
Forum section: electronics / projects

author: dmlandrum
author_rank: Regular Contributor
timestamp: April 06, 2011, 10:24:27 pm
content: I'm currently being tempted by the idea of implementing an analog synthesis system using FPAAs (or the Anadigm dpASP chips, which seem to be similar) and I'm wondering if anyone has any experience with these things. Here are the relevant websites:http://www.anadigm.com/dpasp.asphttp://www.anadigm.com/fpaa.aspThough to be honest, I'm having trouble telling the difference between these two products. They're both capacitor-switched discrete time devices (but still analog because the y-axis is still continuous, like the old BBD chips). Thanks for the help!EDIT: By "analog synthesis" I'm referring to audio/music synthesis, like the old Moog or Oberheim synths.

author: dmlandrum
author_rank: Regular Contributor
timestamp: April 08, 2011, 02:10:11 am
content: I'm guessing these are still a little exotic?I really don't know if they'd lend themselves to voltage-controlled applications, really. I guess I could always just ask the company. Their dev board are just a bit too pricey for a shot in the dark.

author: slburris
author_rank: Frequent Contributor
timestamp: April 08, 2011, 04:01:56 am
content: Wow, I didn't know Anadigm was still around. History hasnot been kind to companies trying to make a go withanalog FPGA's. I know of two that have failed, Motorola, andsomeone else I can't remember.As far as I know, the only success is Cypress with theirPSoC chips, but I don't know if any of them are powerfulenough in an analog sense to do what you want.Scott

author: daedalus
author_rank: Regular Contributor
timestamp: May 10, 2011, 05:38:53 pm
content: I had some dealings with them before, when i was doing investigations into building a custom synth for a friend. At some point in the past Anadigm developed a full synthesiser design using their FPAA parts, it might be worth contacting their sales guys and seeing if you can get your hands on the design. They were not very forthcoming with me, but your luck might be better.
Solved? - Hall effect probe for superconducting magnets - Page 1
Forum section: electronics / projects

author: ChristofferB
author_rank: Frequent Contributor
timestamp: August 01, 2020, 01:19:02 pm
content: Hi all!I've been given a gaussmeter from my uni, a 70's vintage Systron Donner 3101.A probe came along with it, but the probe is clearly from a different instrument, since it has a vastly different connector.I'd like to try and get the probe tested before messing with the huge rack instrument.Here is what is known:- It's a flat ceramic chip hall effect device on the end of a probe, model and manufacturer has been too smudged to read. Probe is potted.- The connector reveals 3 pairs of leads and a shield. I believe the pairs to be coaxial with individual shield:Connector pin wire colors:- White + Black- Red + Black- Green + Black- Cable shield-None of the black wires are connected to each other or to main cable shield.A hall effect device needs a current between two ports, and a voltage differential is extracted via two others:Since a pin is lacking for that, it stands to reason the current supply might be using its shield (black wire?) as return,and the two remaining colored wires are V+ and V-How will I go about testing this? What voltages/currents are usually used with naked Hall effect devices? Keep in mind, I believe modern Hall effect devices already has a regulator and current reference built in.Thanks in advance!

author: ChristofferB
author_rank: Frequent Contributor
timestamp: August 01, 2020, 06:53:12 pm
content: Ok so I've stripped the probe element, and it seems 6 wires lead to it. There is a small black nodule at the silicone strain relief right by the sensor which could be a thermistor, as a hall device really only should need 4 wires. I'm considering breaking these out to some headers for easier access, but it still doesnt solve the issue of pinout...Is there any semiconductor junctions in a hall device that can be checked with a diode checker?

author: ChristofferB
author_rank: Frequent Contributor
timestamp: August 01, 2020, 07:21:23 pm
content: 2 of the leads are almost certainly an NTC - at room temp. They have a resistance between them of 1.8K, when freezed with a freeze spray it shoots up over 10K. (white+black pair)Makes sense for a probe for a cryogenic magnet! That leaves only the 4 wires that would be expected!

author: ChristofferB
author_rank: Frequent Contributor
timestamp: August 01, 2020, 07:38:52 pm
content: Okay, almost got it figured out!Applying +5V through an 1K resistor to the green+black pair gives a voltage between 0 and 1 mV out on the red/black pair when a powerful neodymium magnet is brought near.I still have no idea what voltages/currents is expected for a device like this, although I think sensitivity is set with the bias current.
Filament bulb to heat PCB enclosure - Page 1
Forum section: electronics / projects

author: EEEnthusiast
author_rank: Frequent Contributor
timestamp: November 19, 2019, 07:07:12 am
content: Friends,I am in need for a heat source for my PCB which is enclosed in a metal case. The heat source needs to be controlled using an ON-OFF control using a MOSFET. I was looking at adding a large power resistor, then it stuck me that I could use a filament bulb as well. The objective is to heat the air inside the enclosure, in order to maintain a constant temperature which is higher than the ambient.Does anyone has experience using a filament bulb for this purpose? Any drawbacks using this idea?I plan to use a 12V bulb powered by a 5V source, so that the bulbs life time is extended.thanks

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: November 19, 2019, 07:11:49 am
content: What benefit would the bulb have over a resistor?

author: EEEnthusiast
author_rank: Frequent Contributor
timestamp: November 19, 2019, 07:21:41 am
content: Well, it might add some coolness to the product in addition to the warmth.I am wondering if the filament bulb may be a more effective radiator of heat than the resistor.

author: Psi
author_rank: Super Contributor
timestamp: November 19, 2019, 07:42:42 am
content: Quote from: EEEnthusiast on November 19, 2019, 07:21:41 amResistor = 100% heatLED = 70% heat 30% light (roughly)LAMP = 95% heat 5% light (roughly)

author: Berni
author_rank: Super Contributor
timestamp: November 19, 2019, 08:08:31 am
content: Well a lamp does spread its heat out more because the light it is radiating turns to heat once it hits other things.But yeah since incandescent lamps have really poor efficiency means the majority of the heating is the lamp itself rather than the light. And since lamps burn out eventually it makes more sense to just use a big power resistor instead.

author: EEEnthusiast
author_rank: Frequent Contributor
timestamp: November 19, 2019, 08:13:26 am
content: Thanks guys, i will stick with the resistor as I need not worry about lamp life times.. Will add an Orange LED for the glow.

author: macboy
author_rank: Super Contributor
timestamp: November 20, 2019, 06:17:07 pm
content: One problem with a lamp is that the cold resistance of the filament is much lower than the hot resistance. This can cause a current surge at startup of maybe 5x to 10x the nominal current. This in not the case for a simple power resistor. You might also consider that a bright light can affect operation of components. Not only will they be directly heated by the radiant energy (large dark components may get hotter than small or light colored ones, when the light is on), but semiconductors are light sensitive. Any glass package diode will behave differently depending if the light is on or off for example.

author: EEEnthusiast
author_rank: Frequent Contributor
timestamp: November 21, 2019, 05:36:18 am
content: Thanks all for the responses. Those were very helpful. For now it a 2W resistor that will do the heating duties.
Filling in missing connections on a schematic - Page 1
Forum section: electronics / projects

author: metertech58761
author_rank: Frequent Contributor
timestamp: February 07, 2024, 05:24:20 pm
content: Some time back I decided to see if I could reverse engineer a board from a couple close-up photos just for grins since I didn't want to spend > $200 just to get my hands on one for a closer look.The board in question controls a pair of solid-state relays for a heating system.I got 98% of the board figured out, but there remain several connections where the traces are obscured by parts or run underneath one IC.Here's the schematic I worked out, with the six remaining connections highlighted with ?Hopefully someone has an idea of where the remaining connections should go.
Film capacitors are polarised…? - Page 1
Forum section: electronics / projects

author: LektroiD
author_rank: Frequent Contributor
timestamp: July 09, 2015, 06:47:57 pm
content: Apparently…

author: Len
author_rank: Frequent Contributor
timestamp: July 09, 2015, 06:51:32 pm
content: https://www.eevblog.com/forum/projects/are-your-capacitors-installed-backwards/

author: helius
author_rank: Super Contributor
timestamp: July 09, 2015, 06:59:27 pm
content: Notpolarized, but one pin meets the outer layer.
Film Capacitors Not for High Frequencies? - Page 1
Forum section: electronics / projects

author: laingalion
author_rank: Contributor
timestamp: January 16, 2014, 11:43:40 pm
content: So from I read from the wiki and people talking on forums, film capacitors are great for high frequency stuff.I need a reliable capacitor that can handle high voltages at high frequencies (50V peak at 60 kHz, square-ish waves from full bridge amp).I went looking at datasheets and I noticed that for high frequencies the "permissible AC voltage" drops FAST.Example, page 15:http://www.farnell.com/datasheets/1468249.pdfand page 35 (3rd pdf page):http://www.farnell.com/datasheets/815363.pdfAre there film capacitors that work in high voltage and high frequencies? Do they exist? Or am I misunderstanding the datasheet and/or how film capacitors work?

author: The Electrician
author_rank: Frequent Contributor
timestamp: January 17, 2014, 01:21:07 am
content: Look up the specs on metallized polypropylene capacitors, MKP style.

author: Rufus
author_rank: Super Contributor
timestamp: January 17, 2014, 01:45:22 am
content: Quote from: laingalion on January 16, 2014, 11:43:40 pmHigh frequency and high voltage across a capacitor means high current which means resistive and dielectric losses cause the capacitor to heat up. The Wima data sheet states the plots are for a 10 degree C internal temperature rise.The plots are more maximum dissipation rating than maximum voltage rating.

author: laingalion
author_rank: Contributor
timestamp: January 17, 2014, 02:03:09 am
content: Quote from: Rufus on January 17, 2014, 01:45:22 amThat makes sense.Doing a bit more thinking about my application I realized these capacitors will not be seeing the full wave, but rather ripples. I will be using these as snubber capacitors connected between the full bridge source voltage and ground, and will be placed right next to the MOSFETs. If the rating graphed is due to the dissipation rating then I can likely get away with a much larger voltage.Thanks a lot, saved me a ton of trouble redesigning.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: January 17, 2014, 01:57:14 pm
content: You need the lowest dissipation factor you can find at the frequency of interest, and that's usually polypropylene. Just as a reference point, I built a small induction heater running at a similar frequency. The resonating cap was a very low loss polypropylene, yet it still got hot and I was duty cycle limited! Several caps in parallel can solve the problem.
Filter(?) capacitor for radio - Page 1
Forum section: electronics / projects

author: okw
author_rank: Frequent Contributor
timestamp: April 21, 2023, 02:19:18 pm
content: I have a question about the capacitor C9 in the schematic for si4455 (433MHz). I don't have 270pF, but 220pF and 330pF. What effect would I see from going up or down on capacitance on this one?And would this be dependent on my antenna design?

author: wasedadoc
author_rank: Super Contributor
timestamp: April 21, 2023, 02:53:33 pm
content: It is just a decoupling capacitor from a power rail to zero volt rail. Any of the 3 values will work just fine. No correlation with antenna design.

author: okw
author_rank: Frequent Contributor
timestamp: April 22, 2023, 05:23:10 pm
content: Thanks! Same question goes for CC1I guess this is to filter out DC? Going from 270pF to 330pF would be a big deal?
Filter options is not working on LCSC - Page 1
Forum section: electronics / projects

author: jealcuna
author_rank: Contributor
timestamp: July 18, 2021, 01:57:35 am
content: Has anybody else experimenting issues with filter in LCSC?The filters suddenly show less options and even the few ones are not working showing as result one o two components.

author: Miti
author_rank: Super Contributor
timestamp: July 20, 2021, 12:32:21 pm
content: Yeap, completely broken. I used it last week and it was ok. Maybe they tried to “improve” something.

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: July 21, 2021, 09:16:41 am
content: I noticed the same yesterday. They've done and gone full DigiKey. Never go full Digikey. It doesn't really matter though as essentially everything is out of stock.