hybridfree/eevblog-posts huggingface dataset:
BQ51013B qi receiver - Page 1
Forum section: electronics / beginners

author: mrmp17
author_rank: Contributor
timestamp: October 07, 2014, 04:47:50 pm
content: Hi!I'm putting together qi wireless charging receiver based on TI's BQ51013B. Everythink seems straight forward except connecting ILIM and FOD pins. In pin functions section in the datasheet it's written that you should connect ILIM to VSS (voltage out right?) via calculated resistor and connect FOD pin to ground via 188ohm resistor. But in typical aplication shematics those pins are connected together with resistors and they also connect to RECT and OUT via two resistors (see shematics in datasheet). How do I know how to connect them and what are the resistor values?Datasheet:http://www.ti.com/lit/ds/symlink/bq51013b.pdf

author: PA0PBZ
author_rank: Super Contributor
timestamp: October 07, 2014, 06:36:50 pm
content: Yes, it looks very confusing.First: VSS is normally used for ground or minus, but in the schematics it is connected to Vout.The ILIM pin is, as the name suggests, the current limiter and the datasheet tells you how to calculate the resistor:Programming pin for the over current limit. Connect external resistor to VSS. Size RILIM with thefollowing equation: RILIM = 250 / IMAX where IMAX is the expected maximum output current of thewireless power supply.Not sure what to believe here, because they say to connect it to VSS?The FOD (Foreign Object Detect) pin seems happy with a 188 Ohm resistor to ground,But then you have to use either Ros1 or Ros2, and the value is a mystery to me. Here is what a TI Employee has to say about it:(http://e2e.ti.com/support/power_management/wireless_power/f/693/t/275054.aspx)The ROS1/ROS2 resistors are used as part of the Foreign Object Detection (FOD) scheme, along with RFOD. These resistors are used as part of a calculation to estimate the power level to be sent to the transmitter.The ROS1 resistor would be tied between OUT and FOD. Or, the ROS2 would be tied between RECT and FOD.Using ROS1 on OUT gives a more stable voltage source than RECT, but then there would always be a resistive load on the OUT pin (on the battery). The RECT pin changes voltage levels based on the load. The key to this is that the FOD concern is during higher power levels when RECT is much more stable (close to OUT voltage). Most systems use the resistor between RECT and FOD.That doesn't really help. I also wonder what that does to the value of Ri (the ILIM resistor) because it is in series with either Ros1 or Ros2.Here is another discussion, this time even with a schematic with values:http://e2e.ti.com/support/power_management/wireless_power/f/693/t/282054.aspxSorry if this didn't help, it is all I could find at the moment.

author: mrmp17
author_rank: Contributor
timestamp: October 07, 2014, 07:06:39 pm
content: Thanks a lot!I guess I'll just try it out and see what works best. Looking at evaluation module user guide, resistor from ILIM to OUT is open and ILIM to RECT is fitted with 20K resistor. But then I have no idea what to place between ILIM and FOD. On evaluation module it's selectable - 5k pot or 110ohm resistor (but in BOM it's marked as 75ohm).
bq76920 query - Page 1
Forum section: electronics / beginners

author: alecjw
author_rank: Newbie
timestamp: April 03, 2015, 12:20:50 pm
content: (EDIT: I meant to post this to the projects, designs and technical stuff board - could someone move it please? Thanks!)Hi guys,I've been hacking mySinclair C5a bit lately, and at the moment I'm trying to design a control/protection circuit for the battery pack. The main chip on it is going to be a TI bq76920. It looks like a great chip which does most of the things I want to do, but I have one problem with the datasheet.On page 43 of thedatasheet, it shows a configuration with two anti-series MOSFET to open and close the pack output. What confuses me though is that it's possible to have CHG on and DSG off or vice versa. This means current can flow in one direction through one of the FETs but has to go through the body diode of the other. That body diode would then get very hot. It seems to me that the more sensible way to do it would be to have them both switched together, so they're either both blocking or both conducting.Does anyone know what they're trying to do here? I'm tempted to just AND up the CHG and DSC pins so that they're always in the same state.ThanksAlec
Brain Teaser for Gadget Genius's - Page 1
Forum section: electronics / beginners

author: RJSV
author_rank: Super Contributor
timestamp: March 15, 2025, 04:44:23 pm
content: This budget store TOY features spinning LED light show hand-held.

author: RJSV
author_rank: Super Contributor
timestamp: March 15, 2025, 04:50:00 pm
content: The pesky question is, how does the second conductor get through, to the spinning disk ?One of the switched (on-off) wires goes to a copper strip that does commutation, but the other side, the non-swotched side doesn't connect anywhere except to the motor.

author: RJSV
author_rank: Super Contributor
timestamp: March 15, 2025, 04:53:52 pm
content: ,,,but yet that side DOElpS connect, to the motor lohousing, somephow, omaybe internal but that would require a custom order, of toy type motors

author: SteveThackery
author_rank: Super Contributor
timestamp: March 15, 2025, 06:52:34 pm
content: https://www.eevblog.com/forum/beginners/why-writing-style-and-grammar-matters-in-posts/

author: RJSV
author_rank: Super Contributor
timestamp: March 21, 2025, 01:18:29 am
content: Sorry I've been busy elsewhere:I mis-worded the issue, as the motor DOES get the case grounded (or simply connects to battery minus (-). Just that there isn't a stray blob of solder shorting to the minus terminal.Could there have been a special run at the factory, for placing a deliberate case connection ? That would explain how that connection is being made,,, it's just that I've never seen such a modification, to such a very high volume of toy and miniature motors.The voltage delivered will be with some noise, due to the minus supposed be to lltoy going by way of the moving metal shaft, (and so creates a rubbing effect similiar to o other commutators.l

author: MarkT
author_rank: Frequent Contributor
timestamp: March 23, 2025, 11:35:11 am
content: Quote from: RJSV on March 15, 2025, 04:50:00 pmSurely you know the answer - "don't turn it on, take it apart!!" You have the toy, we don't, you are the only person in a position to investigate. We know its done somehow.
Brainstorming making PSU for 24+3 White LED flashlite - Page 1
Forum section: electronics / beginners

author: lordvader88
author_rank: Frequent Contributor
timestamp: February 21, 2018, 06:07:29 pm
content: I was given a broken flashlite that ran off 3 series AA batteries with 1 current liming resistor, on V+.It has a switch between 3 edge or 24 front white LEDs in parallel. I know some will pass a lot more current than others. I want to make something using old pulled transistors with 1 overall variable resistor turning the max current up to 30mA average on LEDs that pass the most current.I can adapt the PCB to 4 rows of 6, or even 6 rows of 3. I don't want to make 9 current mirrors(although it would be fun to solder).I also don't want to use an LM317, I want to use my basic know how of BJT regulators and current mirrors. I have lots of adjustable voltage references like TL431 and 2.5V LM336.I also want it to run off 9V or 12V since they are the walwarts I have. I could use a switch between 2 biasing paths or IDK yet.I'm disappointed at the brightness of 24LEDs at 325mA Thas was with 3.1V across 24. So this won't help much as the soldering station lights vs my room lights. Oh well.Any thoughts ?

author: Audioguru
author_rank: Super Contributor
timestamp: February 21, 2018, 06:30:22 pm
content: The LEDs in parallel on my cheap Chinese 24 + 3 flashlight are matched pretty well so all the LEDs draw about the same current. But the cheap switch is failing to make good contact so I must turn it on and off a few times to make it work. When the switch works it makes plenty of light.24 LEDs totalling 325mA is 13.5mA each. Their absolute maximum current is probably only 30mA each if you cool them somehow which will appear only a little brighter.For more light you need many more little LEDs or a few large 3W to 10W LEDs.

author: lordvader88
author_rank: Frequent Contributor
timestamp: February 21, 2018, 06:43:11 pm
content: Yeah I don't know about guessing the trace size, etc but I don't want to try 0.96A total . With the 5.7R 1/2W resistor in there I tried ages ago, at 325mW its too hot to touch for long. I think it had a 1R or 10R in there, and at a max of 4.5V none of them are on much tho.With V+3.88 and 3.03V arcoss the LEDs it pulls 165mA. At 2.94V+ and 2.75V LEDs its only 44mA or about 1.83mA each.
Brand new $20 Fluke 15B - Page 1
Forum section: electronics / beginners

author: bc888
author_rank: Regular Contributor
timestamp: September 24, 2018, 12:34:31 pm
content: Always suspicious of anything made in China....although I know Fluke has a facility over there and ebay is doing pretty good monitoring for counterfeits. Is this real Fluke?https://www.ebay.com/itm/FLUKE-15B-Digital-multimeter-Tester-DMM-with-TL75-test-leads-FLUKE-15B-Digital-1/132792320948?epid=0&hash=item1eeb0a03b4%3Ag%3AjwoAAOSwGbhazCtD&LH_BIN=1

author: keymaster
author_rank: Regular Contributor
timestamp: September 24, 2018, 01:57:36 pm
content: Quote from: bc888 on September 24, 2018, 12:34:31 pmsince whenebay is full of fake and counterfeits products . and this seller has only 20 transactions .most likely are stolen or fake for that price.

author: retiredcaps
author_rank: Super Contributor
timestamp: September 24, 2018, 06:46:27 pm
content: It's a real Fluke, but seller is likely a scammer. Seller will take money, but not ship anything.We have seen this before over the years. $10 for a Fluke 17B, etc, etc

author: jeffreyjames44
author_rank: Contributor
timestamp: September 24, 2018, 07:27:32 pm
content: Have had issues with knock off stuff in the past. I would contact the seller to confirm.

author: tautech
author_rank: Super Contributor
timestamp: September 24, 2018, 07:39:46 pm
content: Looks too good to be true.When I was buying 15B's in bulk they still cost ~$60 ea.

author: FotatoPotato
author_rank: Regular Contributor
timestamp: September 24, 2018, 07:43:58 pm
content: Seems like a fake to me. Any multimeter made by fluke that is under $100 just sounds too good to be true

author: Mr. Scram
author_rank: Super Contributor
timestamp: September 24, 2018, 08:24:27 pm
content: Low feedback seller, price too good to be true and a popular item. That's a scammer if I ever saw one.

author: bc888
author_rank: Regular Contributor
timestamp: September 24, 2018, 11:03:10 pm
content: Thanks, yeah, I needed to look more critically at that. I see some guy with 100% rating is selling the same thing out of Oklahoma for $29 each. Has like 10 genuine Fluke 15B+. A slower look at the 60 ratings the seller has shows them to all be purchases, not sales. This is the persons first sale.Ordered a second Dave BM235 (I've had a couple of chances to use the NCV on it) so I don't need a Fluke......but that yellow color is so enticing....

author: GregDunn
author_rank: Frequent Contributor
timestamp: September 25, 2018, 04:43:20 am
content: I've had excellent luck cruising pawn shops; sometimes the shop has no idea how much a multimeter is worth. I've picked up a Fluke 73 for about $30, a 115 for $50 and a 179 for $70 - all in excellent working condition if a bit dirty. But the dirt comes off and they're all clean inside. In my experience with Flukes, as long as the display works (obviously a condition for purchase) the meter has been in spec. There's currently a glut of 323/324 meters like new in cases around here, though not at such a good price. Not a bad way to get into the yellow cased meters without going bankrupt.
brd. file disappeard from project folder - Page 1
Forum section: electronics / beginners

author: amin08
author_rank: Contributor
timestamp: November 10, 2017, 06:34:01 am
content: Hi!Yesterday I was finishing my brd. file design, and then when I closed the project and opened t¡it again I only found sch. file, brd. file has disappeared. Please, can anyone help me, because I've been working on this project since a lot of time.
Bread Board - Page 1
Forum section: electronics / beginners

author: M0BSW
author_rank: Frequent Contributor
timestamp: August 04, 2013, 03:07:36 pm
content: I know ~I'm a bit slow, thought I'd get that one in before anyone else did.But I finally got into bread boarding , I Used to just build straight on to a bit of vero, try and solve any problems later, but now I bought a double bread board, and a box full of link wires, I may not waste so many components, and I think will allow me to correct errors more easily.

author: metalphreak
author_rank: Frequent Contributor
timestamp: August 05, 2013, 01:18:00 pm
content: Yep, breadboards are incredibly handy for knocking up a circuit quicklyI made these little power supply boards a while ago (5V/3.3V switchable) because I always found it a pain to hook up wires from a bench supply.

author: SLJ
author_rank: Frequent Contributor
timestamp: August 05, 2013, 01:48:40 pm
content: I built this top one in the 1980s with fixed and variable power supplies, a DVM, clock, etc. I've gotten a lot of use out of it over the years.The middle one is a newer one I bought. It's made by RSR and has a built in function generator and power supplies. It looks new so I could not pass it up for $40.A lot of these show up on ebay for cheap.The bottom one is a Heathkit Microprocessor Trainer from the 1970s that I added to the collection. Not as good for analog but it has an on board 6800 microprocessor, hex keypad and display. I'm a sucker for the vintage stuff.
Bread board - Page 1
Forum section: electronics / beginners

author: M0BSW
author_rank: Frequent Contributor
timestamp: February 06, 2013, 05:44:17 pm
content: not one for rushing into things ,but I just bought my first breadboard, and how did I ever manage without one , it has1260 contacts + & - power rails with bindind post 3 infact red ,black, green, and I'm really enjoying making things before comitting to vero board, which was the way I used to do it , wasted a lot of boards, not aa many now I hope, next I'll get some fero acid and have a go at making my own custom boards, mind you there's no rush here. one step at a time you know

author: AmirTheGreat
author_rank: Unknown
timestamp: February 20, 2013, 03:19:30 am
content: I'm interested in making some PCB as well. take some pictures during your process for newbies like me please

author: brainwash
author_rank: Frequent Contributor
timestamp: February 20, 2013, 06:30:01 pm
content: I just tried using normal paper on the laser printer and it still works. So this might be the cheapest (and one of the lowest quality) ways of doing PCB.Eagle -> Print (mirrored, black, upside down, solid) -> put the board on the paper, fold paper on edge -> run through the laminator 4-5 times (2-3 times on each side) -> submerse under water 15 minutes -> clean paper and etchYou have to add a thick edge around the circuit because the sides will probably be lost, like in the attached photo.This is probably the dirtiest method of getting circuits done, using just normal copier paper and no tape to hold it down.
Breadboard Amp Rating - Page 1
Forum section: electronics / beginners

author: made2hack
author_rank: Frequent Contributor
timestamp: March 21, 2014, 03:57:06 pm
content: Hello all,According to a previous post,https://www.eevblog.com/forum/beginners/usual-specs-of-a-breadboardprotoboard/, breadboards are not meant for high current.I want to prototype a schematic which will have 40V/1A going in and around 38V/0.8A going out.Can a breadboard handle this?If not, what is an alternate prototyping method?

author: made2hack
author_rank: Frequent Contributor
timestamp: March 21, 2014, 03:58:25 pm
content: If anyone cares, I am using an Olimex breadboardhttps://www.olimex.com/Products/Duino/Breadboarding/BREADBOARD-1/and no datasheet, except for size and pitch.

author: Phaedrus
author_rank: Frequent Contributor
timestamp: March 21, 2014, 04:08:24 pm
content: It won't catch on fire or anything, but it's higher than I'd normally like on a breadboard. Consider doing it dead bug style instead--hot glue your components leg-side up on a piece of cardboard and connect things directly using wires.

author: w2aew
author_rank: Super Contributor
timestamp: March 21, 2014, 05:56:48 pm
content: Quote from: trs80 on March 21, 2014, 03:57:06 pmThat is a bit much for breadboards - even a nice high quality 3M unit. I would recommend a direct soldered prototype. There are a lot of different methods that are easily built and modified. I did a video on some of the various techniques several weeks ago...

author: made2hack
author_rank: Frequent Contributor
timestamp: March 21, 2014, 07:55:14 pm
content: Thanks all and very informative videos!
Breadboard and ground - Page 1
Forum section: electronics / beginners

author: jproject
author_rank: Contributor
timestamp: June 17, 2011, 02:08:48 am
content: Hello everyone,I started playing around with circuits about a month ago and I realized I forgot to set up my breadboard's ground screw as ground. So, how do you set the ground screw to the ground on a large breadboard?Thank you.

author: Simon
author_rank: Unknown
timestamp: June 17, 2011, 05:43:32 am
content: connect it to the negative of the power supply ? if I have understood correctly that it

author: jproject
author_rank: Contributor
timestamp: June 17, 2011, 06:37:20 am
content: Look at this link:http://alienproject.files.wordpress.com/2009/04/gps-breadboard-overview.jpgYou see the black screw in the top middle of the board right? What I meant was how do I make that into a ground when I have one terminal voltage source.

author: Simon
author_rank: Unknown
timestamp: June 17, 2011, 06:43:52 am
content: usually you connect the negative or ground of your power supply to this and then use it to supply negative/ground to your circuit.if your working with batteries and need a physical ground connect it to earth instead (cold water pipe)

author: jproject
author_rank: Contributor
timestamp: June 17, 2011, 08:34:45 am
content: I understand that but I thought there was a way, for an example, to make the oscilloscope provide one terminal AC power source and you connect that to the ground. I remember doing this in a lab a while ago but I guess I'll recheck again to see the full circuit.

author: Simon
author_rank: Unknown
timestamp: June 17, 2011, 01:38:02 pm
content: oscilloscopes don't provide power. the oscilloscopes earth is connected to the mains earth so you may have used that to ground your circuit which saves you the hassle of making up a specific ground wire if you device needs physically grounding
Breadboard from Aliexpress with banana plugs - Page 1
Forum section: electronics / beginners

author: ergya
author_rank: Contributor
timestamp: October 09, 2018, 06:32:33 pm
content: Hi Everyone, I bougth a (let's just say) relatively cheap large breadboard with "external plugs" from AliExpress and I have a question. I took a picture:from the back of the panel because I surprised that the back of the plugs are actually not covered (insulated). Is this normal (speaking of for example an "expensive" breadboard)? Especially because according to the package it can "whitstand" 300V/3-5A. I am just curious I will never let this much voltage/current through the breadboard but are there breadboards (let's assume not from China) which can indeed allow this much voltage/current flow trough it?

author: tooki
author_rank: Super Contributor
timestamp: October 09, 2018, 06:46:08 pm
content: I don’t doubt that the binding post/banana jack can handle that. But I certainly wouldn’t do it when installed into the metal baseplate of the breadboard!!! :pAs an aside, maybe someone can explain to me what good such binding posts are on a breadboard. How do you guys use them? I’ve not found them to be especially helpful, since they’re not wired to anything on the breadboard itself. Do you just run a jumper from the binding post to a power rail? (I’ve done that and it’s just rarely as practical as the banana-to-male-jumper cables I built.)

author: Nusa
author_rank: Super Contributor
timestamp: October 09, 2018, 09:27:16 pm
content: There's no one right way, but the most common is probably to install wire jumpers from the binding posts to breadboard power rails, then to use banana cords between the binding posts and the lab power supply or supplies. Which makes it easier to disconnect and put aside when you need the lab supply for something else.
Breadboard power termination - Page 1
Forum section: electronics / beginners

author: netdudeuk
author_rank: Frequent Contributor
timestamp: March 26, 2019, 11:45:44 am
content: HiWhat does anyone do to terminate multiple power rails (e.g. 5v, +9v, 0v, -9v) for breadboards ?I know that there are things like thishttps://uk.rs-online.com/web/p/breadboards/8352712/, and boards that have 4mm sockets on their baseplates, but they don't seem to add much value.Thanks

author: tggzzz
author_rank: Super Contributor
timestamp: March 26, 2019, 04:08:46 pm
content: Just stick the wires in directly.If you are using solderless breadboards you are already in a state of sin, so one more "suboptimality" won't be noticed.Alternatively consider that every non-soldered connection is a problem waiting to surface, so it is not a good idea to add unnecessary connections.Have fun debugging your solderless breadboard (with parasitic and varying L,C,R); after that you can move on to debugging your circuit.

author: zirconx
author_rank: Contributor
timestamp: March 26, 2019, 05:22:50 pm
content: I discovered these recently:https://www.ebay.com/itm/3X-MB102-Breadboard-Power-Supply-Module-3-3V-5V-for-Arduino-Bread-Board/222743649206it plugs into your breadboard and provides either 3.3v or 5v on both sides.I ordered one. Will be here in a few weeks.

author: netdudeuk
author_rank: Frequent Contributor
timestamp: March 26, 2019, 10:12:25 pm
content: Quote from: zirconx on March 26, 2019, 05:22:50 pmI have quite a few I’d those thanks but I’m referring to multiple rails.

author: netdudeuk
author_rank: Frequent Contributor
timestamp: March 26, 2019, 10:13:20 pm
content: Quote from: tggzzz on March 26, 2019, 04:08:46 pmYes. Factor in the fact that these are Chinese ones and you get to have even more fun

author: Doctorandus_P
author_rank: Super Contributor
timestamp: March 27, 2019, 12:22:55 am
content: A long time ago I used a piece of 10 pin male 2.54mm header.Soldered 5 wires to one wire, and the 5 others to the other wire.Because of the 10 pins and the low profile it's sits solidly in the breadboard.Added a loop from solid 2.5qmm mains wiring.With the loop you can easily pull it out the breadboard and it is also a GND connection for your oscilloscope, DMM, etc.Also added a bit of yarn and glue to increase it's longevity.

author: zirconx
author_rank: Contributor
timestamp: April 06, 2019, 02:29:28 am
content: Quote from: Doctorandus_P on March 27, 2019, 12:22:55 amDoctorandus that is brilliant.I sometimes use these jumpers I made, I soldered on a stub of stiff wire from a resistor, for example. Plugs right into the breadboard.

author: radiolistener
author_rank: Super Contributor
timestamp: April 06, 2019, 05:33:12 am
content: This is how I do
Breadboarding a castellated SMD daughter board  - Page 1
Forum section: electronics / beginners

author: paulca
author_rank: Super Contributor
timestamp: March 29, 2018, 11:44:01 am
content: So I bought myself one of these:https://uk.rs-online.com/web/p/bluetooth-modules/8696218/RN-25 Bluetooth 3.0 Audio module.I am hoping on having a quick play with getting it running on a breadboard.I noticed the castellated pins are only 1.2mm pitch.I would assume my only real option is to solder breadboard jumper wires onto the pins I need and leave the rest floating.Any tips?

author: Rerouter
author_rank: Super Contributor
timestamp: March 29, 2018, 11:45:09 am
content: get a bit of veroboard, solder some pin headers to it, and break it out with mod wire,

author: paulca
author_rank: Super Contributor
timestamp: March 29, 2018, 12:26:11 pm
content: Quote from: Rerouter on March 29, 2018, 11:45:09 amNice idea. Thanks.
Breadboards and MHz - Page 1
Forum section: electronics / beginners

author: paulca
author_rank: Super Contributor
timestamp: November 22, 2022, 07:23:27 pm
content: I googled this before I started and found all kinda of opinions on whether you can successfully run, say a 24Mhz clock on a breadboard. Some saying you can't, most saying you could but really shouldn't, YMMV type thing.This evening I successfully integrated 2 x I2S buses(?) and 1 x SPI bus on a breadboard with a TFT, an ADC and a DAC all running through an STM32F411.It's almost faultless, if you don't nudge it too hardWhat is pretty hilarious is the noise on the analogue ground. A perfect example of why mixed signal applications need special attention. I can literally hear my code. I can hear a lower harmonic of it cycling between doing nothing, rendering the TFT, and processing the audio frames. It's got quite the groove.But thats... lets see...1x24.576Mhz I2S Master clock split 3 ways via the breadboard, making lovely attenna loops in the air of course2x3Mhz (ish) I2S streams/BCK.1x48Mhz SPI clock.1x48Mhz USB clock.And the only fault is the digital switching noise.... and you have to not look at it funny when you move it. Hold you face right of have to fidget a few wires.Breadboard is well caps with all the power rails having a 10uF and a 0.1uF at each device power pick up. The TFT had an additional 10uF on it's pins.From experience I would recommend, if you are powering the board from the MCU pins... don't use 10uF caps. Limit them to 1uF. The MCU does NOT like charging a 10uF cap during boot and will probably bounce a few times.

author: paulca
author_rank: Super Contributor
timestamp: November 22, 2022, 07:28:16 pm
content: Photo:

author: paulca
author_rank: Super Contributor
timestamp: November 22, 2022, 07:37:38 pm
content: Moving the ADC module off the breadboard, uncrossing some lines, adding 100nF right up against all the digital VDD lines, placing 10uFs near the power hungry MCU and TFT about halved the noise.
Break in laminations in an industrial choke?? - Page 1
Forum section: electronics / beginners

author: Chris Wilson
author_rank: Super Contributor
timestamp: September 23, 2014, 04:02:18 pm
content: I have had a choke for a TIG welder rewound and the new choke has issues when set to AC welding. The arc is splattery and unstable. The makers issued a description of how the choke modifies the AC waveform. Looking at how the choke has been wound compared to photos of the old one they were sent to rewind shows the break in the laminations, (some people seem to call it a shunt), is by a different winding bobbin. Let's call one bifilar wound bobbin the input bobbin. This is wired in series with the "output bobbin". The break in the laminations is bridged by a piece of mild steel channel. You can say either the channel section is now by the "input coil" or the input coil in now by the channel. Originally the channel section lamination break was by the output coil. Photo of the original choke hopefully attached, as well as a link to the .pdf file the makers kindly let me have, showing original winding info. I am wondering if the channel being by the wrong coil now could affect its operation in modifying the AC waveform?. Another anomaly of this rewind is when the welder is running AC welding current the steel cabinet sides hum and buzz at about 50Hz, and you can feel the panel vibration as well as hear it. the excitation is in the region of the new choke, and it seems magnetic flux leakage is causing this. The original windings did not do this at all. any clue?Turning it around is possible, but would need some heavy copper straps making to re -orientate the wiring. Thanks!
Breaking out a 0.35mm BGA on a budget - Page 1
Forum section: electronics / beginners

author: kcuzner
author_rank: Newbie
timestamp: February 16, 2018, 04:07:52 am
content: I am looking to see what it would take for me to mess with the iCE40UL FPGA at home, especially to see how small I can get everything. It comes in two packages I'm interested in: a 16-ball 0.35mm BGA and a 36-ball 0.4mm BGA. I'd like to stay with a 2-layer board so I'm favoring the 16-ball BGA, though theoretically the 36-ball should be possible on two layers with appropriate via sizes.The first issue I'm running into is the capabilities available to me on a budget. Normally, I believe the breakout on a BGA this tiny would either necessitate via-in-pad with filled and plated vias or using absurdly small traces to pass between the balls (and that option works only for the 16-ball). However, when I start hunting around, things start to get expensive:- I can only find one vendor that even offers trace widths for low-quantity prototypes below 6/6 (pcbway can do 5/5 and 4/4). I think a 5mil trace is the absolute widest trace I can even begin to think of using.- uVias are not an option I have managed to find. Even moving to 0.25mm conventional drills from the usual 0.3mm increases the cost by over 15x, so I assume if I managed to find uVias they would be absurdly expensive.Now, here's what I understand:- I know I'm running into a technology limit on the trace widths that probably hasn't bubbled up to the low-cost low-quantity hobbyist PCB world.- I won't be able to find uVias at hobbyiest pricing, and even if I did, I think I would need a 4-layer board minimum since I'm pretty sure 62.5mils FR-4 is too thick for a uVia.One potential thing I could tweak is my footprint. The balls on the 16-ball 0.35mm package are nominally 0.218mm and maximally 0.25mm. Right now, I've got my pads sized at 0.17mm with a solder mask clearance of 0.05mm. This is my first time building a footprint without a vendor-suggested option, so I'm not sure how small I can go with the pads before I start running into solderability issues.Here's my question: Does anyone here have any thoughts on how these packages could be broken out on a budget PCB without resorting to high-technology PCB requirements?

author: tautech
author_rank: Super Contributor
timestamp: February 16, 2018, 04:16:04 am
content: https://www.eevblog.com/2017/10/06/eevblog-1029-bga-pcb-fanout/

author: kcuzner
author_rank: Newbie
timestamp: February 16, 2018, 04:41:37 am
content: Oh man I didn't remember that one! Excellent!However, he does use the 4mil traces so I'm starting to become more doubtful I'll be able to do this for a reasonable cost in low quantity.

author: tautech
author_rank: Super Contributor
timestamp: February 16, 2018, 04:49:48 am
content: Quote from: kcuzner on February 16, 2018, 04:41:37 amWatch it again and again. There's lots to learn from Dave that used to do this stuff as a job and for years and years.
Breakout PCB electric path between any two pins - Page 1
Forum section: electronics / beginners

author: stafil
author_rank: Regular Contributor
timestamp: March 27, 2020, 12:39:27 am
content: I have a STM32 MCU breakout PCB that I just received from JLCPCB and while I was checking for something I thought I screwed up, I observed that there is always a path between any two pins on the board (the resistance is in the order of MOhms). It this normal and expected?PS: It's not the mat.

author: JustMeHere
author_rank: Frequent Contributor
timestamp: March 27, 2020, 02:49:56 am
content: Yes. This is very normal.

author: Gyro
author_rank: Super Contributor
timestamp: March 27, 2020, 09:30:03 am
content: You are measuring a current path through the STM32 that you have soldered on, it's nothing to do with the PCB.Yes, it's quite normal to see some resistance indication when probing between any two pins of an IC.

author: JLCPCB Official
author_rank: Regular Contributor
timestamp: April 03, 2020, 03:11:32 am
content: Yes,the parameter information is here:https://jlcpcb.com/capabilities/Capabilities.It exceeds the production capacity

author: stafil
author_rank: Regular Contributor
timestamp: April 03, 2020, 03:39:43 am
content: Quote from: JLCPCB Official on April 03, 2020, 03:11:32 amThanks. I didn't mean to imply that it was something wrong with the manufacturing. I was afraid I screwed up someway during design, like putting traces too close to each other or something like that.Your service is fantastic, and your prices even more so. I just hope you keep increasing your parts library size. Oh, and I love the small surprise gifts in every orderThanks!

author: JLCPCB Official
author_rank: Regular Contributor
timestamp: April 06, 2020, 02:54:43 am
content: Thank you so much! We are developing our SMT service which means we are going to increase the parts as well, the time needed, you guys support also needed. For the small gift, we will design and offer more practical and interesting little gifts for everyone.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 06, 2020, 07:02:11 am
content: Quote from: JLCPCB Official on April 03, 2020, 03:11:32 amCan you explain what parameter is exceeded, and by how much? I do not see insulation resistance on that page.Tim

author: JLCPCB Official
author_rank: Regular Contributor
timestamp: April 22, 2020, 09:48:13 am
content: please send the question to rebecca@jlcpcb.com. the picture is not clear enough. Thank you
Breathalyzer using an LM324. Can this sensor be bought? - Page 1
Forum section: electronics / beginners

author: Cliff Matthews
author_rank: Unknown
timestamp: November 24, 2017, 02:46:58 pm
content: Just curious.. Seems the heater wire would be so thin that after one drop, and this thing's trash.

author: Lee Leduc
author_rank: Regular Contributor
timestamp: November 24, 2017, 04:22:59 pm
content: https://www.pololu.com/product/1634
Bridge amplifier/complementary push-pull amplifier(class AB) - Page 1
Forum section: electronics / beginners

author: hung211203
author_rank: Newbie
timestamp: April 15, 2023, 10:19:45 am
content: Hi guys i'm working on a project involving the bridge amplifier using class AB input(this is what its called at my place) and im struggling to figure out which circuit would be the correct one. On the web, i searched it but it keeps showing me the circuit but using ICs instead of transistors, and it's really difficult to solve the IC with electronics math. Also i found a limited sourse showing that i need to use 2 pairs of transistors with a pair consists of a NPN and a PNP; i think this is only the input or something im not sure because i have another document but its showing the OTL amplifier but also uses 4 transistors with output power of 60W and im trying to design a bridge typed one with 80W output power.Do you have any useful video links or books i can have the electronics solution to understand the circuit and to design one by myself?Thank you for reading this. Also i wil send a png file of the OTL amplifier below, i don't know if its relevant to my bridge type.I will mostly check my messages in e-mail so if i dont reply to you soon in here then i'm sorry. Have a great day!

author: barshatriplee
author_rank: Regular Contributor
timestamp: April 15, 2023, 11:20:08 am
content: Are you trying to make this type of AMP?https://www.electronics-tutorials.ws/amplifier/class-ab-amplifier.html
bridge or center tapped rectifier question (Is it obsollete?) - Page 1
Forum section: electronics / beginners

author: 001
author_rank: Super Contributor
timestamp: November 19, 2018, 10:29:53 am
content: Hi!I see that simple brige rectifier is ok for most of classic PSsBut what about advantage of "center tapped transformer + two diodes" and "center tapped transformer + brige" circuits?Is it obsollete?

author: mvs
author_rank: Frequent Contributor
timestamp: November 19, 2018, 11:54:14 am
content: Quote from: 001 on November 19, 2018, 10:29:53 amOn the one hand less diodes means better efficiency and less heat. On the other hand it requires more copper in the transformer.This rectifier topology is commonly used in SMPS supplies (push-pull, half-bridge, full-bridge topologies), since at high frequency the transformers are small, and copper usage is not a concern.QuoteIt is useful for dual power supplies, since center tap is half voltage point. You will find this rectifier for example in audio amplifier or linear lab power supplies. Or even in power supplies of PCs to generate +12V and -12V rails (with unsymmetrical rectifier, 2 large Schottky diodes for +12V rail and 2 small diodes for -12V rail).

author: floobydust
author_rank: Super Contributor
timestamp: November 19, 2018, 07:14:22 pm
content: Full-wave center-tapped (two-diodes) is no longer popular.The reason is transformer utilization. Only half (one) secondary winding is being used so you need more copper on the transformer. It's one diode+sec winding or the other that have current flowing.For this reason, it is higher cost even though with FWB you need two more diodes to make a bridge.
Bridge rectifier current - Page 1
Forum section: electronics / beginners

author: Jwillis
author_rank: Super Contributor
timestamp: November 29, 2019, 04:59:37 am
content: How do I determine the current rating of a full bridge rectifier. I'm thinking it to be the same as the current rating of any one of the diodes used. But them I'm thinking that any one diode will only pass current every half cycle. So I could use lower rated diodes than the current i want to pass. Or am I second guessing and the first idea is correct?

author: floobydust
author_rank: Super Contributor
timestamp: November 29, 2019, 06:54:47 am
content: The current rating is for any one diode, as far as the junction's capability.But in a bridge rectifier, the diodes are on in alternating pairs, so heat is generated from two diodes. The package might not actually be able to dissipate the heat even though the diodes have the current rating. Both parameters have to be considered.Careful if you have a capacitive load, the current waveform is not sinusoidal at all. But the rectifier's datasheet usually assumes 50/60Hz sine loads for the ratings.On power up there is a surge for many cycles until a filter capacitor charges up.

author: gbaddeley
author_rank: Regular Contributor
timestamp: November 29, 2019, 09:50:02 am
content: Lower rated diodes than what is needed is generally a bad idea. It leaves no margin for overload or thermal demands and will probably fail in the long run. As an estimate, I suggest a rating at least 2 - 4 times the average current.

author: Jwillis
author_rank: Super Contributor
timestamp: November 30, 2019, 08:53:24 am
content: Thanks for the help.I was trying figure out why I was getting such screwy wave forms on the scope so I thought the rectifier was hosed. Since I didn't have one rated for what I needed I could throw something together to get me going again . But after some contemplation I realized that in order for the rectifier to work properly it needs a load on it .. Slapped 100k resister across the positive and negative now it works as expected.
Bridge Rectifier datasheet questions - Page 1
Forum section: electronics / beginners

author: advark
author_rank: Contributor
timestamp: July 25, 2022, 03:57:58 am
content: Hi everyone,I need to use a bridge rectifier for a device that will draw around 3.5A from a 18VAC supply. Typically, a GBU/KBU device has more or less 1V drop per diode according to a few datasheet that I looked at. So that will mean a 7W power dissipation. Most of these devices can be used up to 3A without a heatsink (yeah, lucky me!).Here is a few that I looked at:Vishay KBU4Ahttps://www.vishay.com/docs/88656/kbu4.pdfGeneSIC GBU4Ahttp://www.diodemodule.com/bridge-rectifier/gbu/gbu4a.pdfOnSemi GBU4Ahttps://rocelec.widen.net/view/pdf/s2epgwqjmy/ONSM-S-A0003587643-1.pdf?t.download=true&u=5oefqwMCC GBU4Ahttps://www.mccsemi.com/pdf/Products/GBU4A-GBU4M(GBU).pdfQuestion 1:The Maximum Average Rectified Current. What does the "Average" means? Is it the average as in IAV= IPK* 0.636 as opposed to IRMS= IPK* 0.707?Question 2:Since I will be dissipating 7W, I will require a heatsink. Now, the thermal resistance is specified (per leg) as RJL=X°C/W (RJLinstead of the usual RJC). What the heck is a leg? My guess is that since each half cycle of the AC goes through 2 diodes, a leg is 2 diodes? Which means that each full cycle will go through 2 legs (positive and negative) and the thermal resistance will be twice RJLThanks for any hints.

author: bob91343
author_rank: Super Contributor
timestamp: July 25, 2022, 07:04:40 am
content: A leg is one diode.

author: Benta
author_rank: Super Contributor
timestamp: July 25, 2022, 10:22:04 am
content: If the bridge is followed by a storage capacitor, you should select a bridge bigger than that. The current will have a very large peak value.
Bridge Rectifier Dissipation - Page 1
Forum section: electronics / beginners

author: boatanchorguy
author_rank: Newbie
timestamp: January 15, 2018, 04:40:53 pm
content: With a basic 4 diode bridge rectifier where there is no load - just open circuit on the output side - am I correct that the only energy expended in this system would be heat due to the voltage drops across the diodes?

author: rx8pilot
author_rank: Super Contributor
timestamp: January 15, 2018, 04:44:15 pm
content: An open circuit has no current. Without current, there is no heat.Short and misplld from my mobile......

author: TimNJ
author_rank: Super Contributor
timestamp: January 15, 2018, 05:18:29 pm
content: Not sure the context of your question but yes, without any current, there cannot be dissipation.On a side note, if you try to probe a bridge rectifier open circuit (or effectively open circuit with a 10M scope probe), you may see some weird nonlinear waveforms. Apply a little load to it and you’ll see what you’d expect.

author: madires
author_rank: Super Contributor
timestamp: January 15, 2018, 05:37:50 pm
content: There would be a negligible small power loss because the diodes have a tiny leakage current.
Bridge rectifier identification  - Page 1
Forum section: electronics / beginners

author: decoder_82
author_rank: Regular Contributor
timestamp: February 09, 2024, 07:59:19 am
content: Hello,I found this bridge rectifier. See the picture below. It is an AEG B30/24.According to what I found online it is a bridge rectifier.I am wondering from what kind of device it comes from ? Anyone has information?Many thanks in advance

author: soldar
author_rank: Super Contributor
timestamp: February 09, 2024, 08:25:05 am
content: I remember those. Fifty years ago they were widely used in consumer electronics. Had a very characteristic smell.https://en.wikipedia.org/wiki/Selenium_rectifierIn the early stage of failure they produce a modest amount of sweet-smelling gas. Sometimes described as 'sickly-sweet'. At that point the rectification properties are almost totally gone, allowing reverse voltage to leak through the rectifier. During catastrophic failure they produced significant quantities of malodorous and highly toxic hydrogen selenide that let the repair technician know what the problem was. By far the most common failure mode was a progressive increase in forward resistance, increasing forward voltage drop and reducing the rectifier's efficiency. During the 1960s they began to be superseded by silicon rectifiers, which exhibited lower forward voltage drop, lower cost, and higher reliability.

author: decoder_82
author_rank: Regular Contributor
timestamp: February 09, 2024, 08:31:19 am
content: Thanks ! Do you have example of appliance / device using them ?

author: retiredfeline
author_rank: Frequent Contributor
timestamp: February 09, 2024, 08:56:21 am
content: I last saw them in valve TVs when I was a kid. But even by then silicon rectifiers had started to displace valve and selinium rectifiers, so I never had to deploy one.

author: soldar
author_rank: Super Contributor
timestamp: February 09, 2024, 04:32:34 pm
content: My sister had a record player of the type that was like a portable case with a handle and the lid was the loudspeaker and the base had the turntable and amplifier and it had one of these selenium rectifiers. I reckon it was around 1967. It was not on any PCB but screwed directly inside the wood case, same as the transformer..Soon later I saw the first silicon diodes, I believe they were BY127, with bright red body with square section, not round and black like they would be later. I might still even have one of those old ones in my generic diode drawer.
Bringing audio into a PC from a waveform generator? - Page 1
Forum section: electronics / beginners

author: elroy
author_rank: Regular Contributor
timestamp: May 08, 2019, 09:58:36 pm
content: Recently I downloaded the software Spectrum Lab (https://www.qsl.net/dl4yhf/spectra1.html), and would like to bring some audio into my PC to play around with it.Can I just generate audio with my Siglent SDG2042X waveform generator, rig up a BNC-to-1/8" cable and plug the Siglent's output directly into a USB sound card?

author: ogden
author_rank: Super Contributor
timestamp: May 08, 2019, 10:11:13 pm
content: Yes indeed. Just make sure to not exceed consumer audio line level specs, −10 dBV (0.9V peak-peak).
broadcom chip datacheet  - Page 1
Forum section: electronics / beginners

author: loordgek
author_rank: Contributor
timestamp: March 04, 2021, 06:42:25 pm
content: i am looking for info for this chip but i don't know how to google itand is it possible to run custom linux on it

author: Terry Bites
author_rank: Super Contributor
timestamp: March 04, 2021, 09:12:41 pm
content: What PCB is that chip on?BCM7229ZZKFEB03G?

author: loordgek
author_rank: Contributor
timestamp: March 04, 2021, 10:09:38 pm
content: it is from a Kamai entone 510b

author: amyk
author_rank: Super Contributor
timestamp: March 05, 2021, 02:55:56 am
content: Broadcom? Datasheet?Broadcom is already one of the most infamous companies for not releasing any documentation about anything. Especially for a set-top box, they are going to be even more secretive.You'll have to do some really hardcore reverse-engineering if you want to do anything with that.

author: mon2
author_rank: Frequent Contributor
timestamp: March 05, 2021, 04:39:31 am
content: https://gathering.tweakers.net/forum/list_messages/1763209

author: rfclown
author_rank: Frequent Contributor
timestamp: March 05, 2021, 05:52:06 am
content: Quote from: amyk on March 05, 2021, 02:55:56 amBefore I scrolled down and saw this response, that was my precise reaction. Even when you are designing with their parts it's hard to get the datasheets. We are using some Broadcom parts at work. NDA required. If they give them to you, they will have your company name plastered on every page over the text indicating that it is confidential so that you can't leak the information.

author: james_s
author_rank: Super Contributor
timestamp: March 05, 2021, 06:44:40 am
content: I used to work for a company that used a lot of Broadcom SOCs. I had to sign a NDA to even look at the schematic, some of the source code was tightly controlled, builds were signed on an airgapped machine that was stored inside a locked vault, it was all a bit over the top. So yeah, good luck finding anything.

author: Ice-Tea
author_rank: Super Contributor
timestamp: March 05, 2021, 07:39:04 am
content: Quote from: james_s on March 05, 2021, 06:44:40 amSame here. Even though we used insane amounts of BCM chips, Istilldidn't have access to anything I wasn'tdirectlyusing.