hybridfree/eevblog-posts huggingface dataset:
SMD Components popping up - Page 1
Forum section: electronics / projects

author: praveen_khm
author_rank: Contributor
timestamp: October 15, 2014, 06:28:57 pm
content: Hi,I am using a toaster oven to solder smd components. It was all fine till yesterday (tried it yesterday after a gap of 2 months) and when I tried soldering yesterday, the components started popping off from its position just like pop-corn. Has anyone got this issue and have a way to solve this?Just to give a hint, the solder paste seemed dry and I mixed liquid flux into it and then applied it over the board. Secondly, the paste is little old (6 months).Thanks for any help provided.

author: tautech
author_rank: Super Contributor
timestamp: October 15, 2014, 06:54:16 pm
content: It's called Tombstoning as in graveyard tombstone.Google "smd tombstone effect" for lots of info

author: praveen_khm
author_rank: Contributor
timestamp: October 15, 2014, 07:02:22 pm
content: Well tombstone effect is when one side of the component rises and stands like a tomb stone.But here, it just pops out. Jumps away from its location and sits in another location, and few jump out of the board. Seems weird...

author: mrflibble
author_rank: Super Contributor
timestamp: October 15, 2014, 07:06:33 pm
content: Strange. Only thing I can think of is something like flux present in solder paste cooking off ==> gas expansion ==> component goes on vaction. But that is a rather random guess.

author: Legit-Design
author_rank: Frequent Contributor
timestamp: October 15, 2014, 07:10:49 pm
content: Quote from: praveen_khm on October 15, 2014, 06:28:57 pmYou provided the most probable answer yourself, you're welcome.

author: Monkeh
author_rank: Super Contributor
timestamp: October 15, 2014, 07:10:56 pm
content: The flux you've mixed in isn't suitable for solder paste. It's vapourising rapidly and blowing the parts off.You might get away with slowing down the temperature ramp, but the proper solution is to buy fresh paste.

author: praveen_khm
author_rank: Contributor
timestamp: October 15, 2014, 07:21:45 pm
content: QuoteQuoteWell, maybe yes. The logic was since solder paste already has flux in it, what is harm in adding more flux? That seems to be bad.I guess I will pull out some fresh solder paste and try using it.Thanks for the responses....

author: Monkeh
author_rank: Super Contributor
timestamp: October 15, 2014, 07:23:04 pm
content: Quote from: praveen_khm on October 15, 2014, 07:21:45 pmWhat flux was in the paste? ... not the same stuff you added.The air has CO2 in it, what is the harm in adding more?

author: mazurov
author_rank: Frequent Contributor
timestamp: October 15, 2014, 09:52:53 pm
content: Quote from: praveen_khm on October 15, 2014, 07:21:45 pmNext time add less flux. My workflow is this: apply rosin flux to the PCB using an applicator which looks like a felt pen, let the flux dry, then print the paste, populate the board, and reflow as usual. Still, fresh paste and PCBs give better results.
SMD Diode (?) E27 NMC. What is it? - Page 1
Forum section: electronics / projects

author: Aller
author_rank: Contributor
timestamp: March 01, 2023, 06:23:42 am
content: I haveDRUCK UPS-III-IS Loop Calibratorto repair, and I found one faulty diode (O.L. both ways, even out of the circuit). The SMD code on it isE27 NMC.by ON Semi. I can't find anywhere on the internet what kind of diode it is. Being the calibrator, all elements may be crucial, to be exact, so I really don't want to mess up with any diode there. Especially if it needs to be Shottky or a particular Zener. It is connected between a Poly capacitor and in series with another (different) diode (MX47A) - pictures attached.

author: darkspr1te
author_rank: Frequent Contributor
timestamp: March 01, 2023, 09:39:46 am
content: do any of these fit the billhttps://octopart.com/search?q=onsemi+e27&currency=USD&specs=0

author: TurboTom
author_rank: Super Contributor
timestamp: March 01, 2023, 10:05:10 am
content: Could be Fairchild / OnSemiSMBJ64CAbi-directional TVS. Marking code "NM" for 64V breakdown and the "C" maybe for the bidirectional variant. If you measure no continuity whatsoever, I'ld consider the component to be healthy, though.

author: lotas
author_rank: Newbie
timestamp: March 01, 2023, 03:46:06 pm
content: 1SMB64CAT3
SMD DIODE in 0603 case needed "HELP" - Page 1
Forum section: electronics / projects

author: MrsR
author_rank: Regular Contributor
timestamp: September 03, 2012, 03:39:20 pm
content: Hi!Guys,I am trying to repair some Digital Servos and have run into a problem.After a great deal of research I have found all the Data Sheets for the The active components and reverse Engineered the circuit so I have a schematic.The plug from receiver to servo is a 3 pin type that can be put in both ways. The V+ is the center pin at 7.4v to 8.4v DC and the outer pins are V- and Signal.The Signal is an AC 3v to 5v 50Hz square wave with the positive part of the pulse Min. .9ms to Max. 2.1ms.I don't know what the Max. current is but there is a 1k resistor on input to the signal circuit and the max amperage to the ATMEG Microcontroller is 40Ma.The problem:There is a Diode in parallel reverse bias at the input of the voltage regulating circuit from what I can understand it is to protect the circuit from the V+ half of the AC Signal and this Diode I don't seem to be able to find. I have found D size case types but I need a 0603 case size. Can anyone help me please?THANK YOURachael

author: MrsR
author_rank: Regular Contributor
timestamp: September 04, 2012, 05:42:33 pm
content: Thanks,I forgot about ELEMENT14, Ive been using RS lately and I went over and found a couple that would do the job and I found that the HexFets I needed were half the price.Thanks againRachael
SMD glue for bottom layer parts - Page 1
Forum section: electronics / projects

author: bson
author_rank: Unknown
timestamp: December 09, 2015, 04:25:29 am
content: Looking for a heat-cure glue for bonding bottom-layer SMD parts to the board. Don't want them to drop off when I heat the top layer, or put the board on a hot plate... Looking for something for manual assembly. I've only found two-part heat-cure epoxies, and I'm sure these are the bee's knees for mass production, but not so great for manual use. (Or are they?) Am I missing something obvious?

author: jeremy
author_rank: Super Contributor
timestamp: December 09, 2015, 05:51:39 am
content: One part thermal cure (~120C - 150C for a few minutes) is the norm I think, and it usually some red stuff.It's pretty nasty, so make sure the place you buy it from can actually ship it to you. In Australia, no-one would ship it over the ocean, but I ended up finding some from RS locally.Edit: this one:http://au.rs-online.com/web/p/surface-mount-silicone-adhesives/0567581/?origin=PSF_435906|alt

author: rx8pilot
author_rank: Super Contributor
timestamp: December 09, 2015, 07:02:03 am
content: Loctite Chipbonder 3609 is one part. I just ordered a syringe but have not yet received it. Planning to use it with my pneumatic dispenser for manual application.Hope it works.Sent from mobile device.... Keeping it short and mis-spelled

author: bson
author_rank: Unknown
timestamp: December 09, 2015, 09:58:21 am
content: Ah, thanks for the pointers! Ordered some Chipbonder 3621 (10ml, $33! Yikes!) to try out...

author: rx8pilot
author_rank: Super Contributor
timestamp: December 09, 2015, 10:25:59 pm
content: Yes, it is not cheap. I suspect the product will go bad before I use it all. I only have one PCB with heavy parts on both sides.What parts are you needing this for? Have you already checked to see if the surface tension of the solder is strong enough?
SMD Header Pins  - Page 1
Forum section: electronics / projects

author: nicksydney
author_rank: Regular Contributor
timestamp: October 28, 2016, 07:51:37 am
content: Hi,I'm trying to design a small baseboard with Kicad and was thinking of using SMD header pins like this onehttp://www.digikey.co.il/product-detail/en/sullins-connector-solutions/NPPN161BFLC-RC/NPPN161BFLC-RC-ND/4558093does anyone know whether header pins with the same kind of specs can be bought from eBay or Aliexpress or have comes across in other online shopping website besides digikey ?Thanks

author: sleemanj
author_rank: Super Contributor
timestamp: October 28, 2016, 08:51:10 am
content: SMD headers take up a surprisingly large amount of board space, and are also a bit of a pain to hand solder in my experience, they are also considerably more expensive. If you don't NEED to use surface mount, probably better to stick with through hole.2.54mm (0.1") and 1.27mm (0.05") pitch headers are fairly easy to come by in surface mount forms:https://www.aliexpress.com/wholesale?SearchText=+header+smdno recommendation on any of the vendors, just a search.

author: ebclr
author_rank: Super Contributor
timestamp: October 30, 2016, 12:57:00 am
content: If space is a concern you can use 1.27 mm oneshttps://www.aliexpress.com/item/20-Pcs-Per-Lot-Gold-Plated-Pitch-1-27mm-Male-2x15-Pin-30-Pin-Double-Row/32463176352.html?spm=2114.01010208.3.62.CnCC9n&ws_ab_test=searchweb0_0,searchweb201602_2,searchweb201603_1&btsid=614e9806-a59e-43a8-83e8-d264202cccb9
SMD IC equivalent/replacement of Micro SD card - Page 1
Forum section: electronics / projects

author: ricko_uk
author_rank: Super Contributor
timestamp: January 14, 2021, 09:06:39 pm
content: Hi,can anybody suggest an SMD IC equivalent to a micro SD card?Ideally so it is 100% firmware compatible too so that does not need changing.Thank you

author: tszaboo
author_rank: Super Contributor
timestamp: January 14, 2021, 09:08:33 pm
content: This is not very usual. However, I've just seen that they actually do this, LCSC stocks them.https://hackaday.com/2020/12/29/new-part-day-sd-nand-are-surface-mount-chips-that-work-like-an-sd-card/

author: ataradov
author_rank: Super Contributor
timestamp: January 14, 2021, 09:21:21 pm
content: There are also Micro SD cards that are sold in trays for pick and place machines. You can just treat normal cards and reflow solder them as usual.That chip is neat, but I'm not sure if it is a good idea to rely on a single supplier.Here is an article from 2015http://www.dotmana.com/weblog/2015/08/microsd-card-reflow-quick-and-dirty-pcb-with-kicad/

author: thm_w
author_rank: Super Contributor
timestamp: January 14, 2021, 11:55:07 pm
content: Quote from: ataradov on January 14, 2021, 09:21:21 pmI love that this person was actually thinking about implementing this on a product with a $30k BOM(they never did do it).

author: abyrvalg
author_rank: Frequent Contributor
timestamp: January 15, 2021, 12:04:51 am
content: There are eSD chips (i.e.https://www.flexxon.com/product/memory-card-esd/), but they look quite "niche" (industrial grades, strange manufacturers). The "normal" way of doing this is eMMC.

author: ricko_uk
author_rank: Super Contributor
timestamp: January 16, 2021, 12:08:25 am
content: Thank you all

author: wizard69
author_rank: Super Contributor
timestamp: January 16, 2021, 12:21:18 am
content: Quote from: ricko_uk on January 16, 2021, 12:08:25 amThank you for asking, because now I know that eMMC and SD are of the same family of devices. This little article:https://www.riverloopsecurity.com/blog/2020/03/hw-101-emmc/,is very enlightening. Effectively eMMC are SD cards designed for embedded usage. Didn't know that until today. Apparently eMMC is better performing so that might be a plus for you.

author: ricko_uk
author_rank: Super Contributor
timestamp: January 20, 2021, 08:18:48 pm
content: Interesting article!
SMD identification - Page 1
Forum section: electronics / projects

author: Captainbeaky
author_rank: Newbie
timestamp: August 29, 2018, 05:55:59 pm
content: I've got a large marine inverter in for repair, I've tracked down all but three components, which are proving quite some trouble to find.The inverter is made by Letrika, who have (of course) not been helpful in resolving a long standing issue with this inverter...Firstly, I have one SOD-123 size diode:- The code is 4 characters, 2 above 2 below with the diode stripe underneath:- E1 RG (and then the diode stripe, which consists of three single laser engraved lines)I think this is a BZT52H-20??Then there are two SOT-23 size packages that have me stumped, the codes read as 5 characters in a line, with the middle character "C" double underscored with two parallel lines). These are absolutely identical looking - they look like they are from the same manufacturer.They are:-L8C3E and N9C3CI thought I found these as IRLMl0020 and IRLML2060 respectively, but on closer inspection (and testing on the board), this does not hold water, and the component marking is not quite the same as the data sheet.These are used in the drive circuit of a large SEMIKRON IGBT block, and appear to be connected in "totem-pole" pairs on the high side and low side. I initially thought they were pairs of BJT's in a "push-pull" layout, but on closer inspection of the connections, this wouldn't make sense.I've dug around for these in the following places:-http://caxapa.ru/thumbs/588912/smd-codes.pdfhttp://www.marsport.org.uk/smd/mainframe.htmhttp://www.s-manuals.com/smdNothing comes out at being suitable or likely!Any clues or places I haven't looked yet?Thanks in advance.Mike.

author: amyk
author_rank: Super Contributor
timestamp: August 29, 2018, 08:15:28 pm
content: Post pictures please...

author: Captainbeaky
author_rank: Newbie
timestamp: August 30, 2018, 08:21:50 am
content: Here it is...
SMD inductors - liability to couple with external LF magnetic fields? - Page 1
Forum section: electronics / projects

author: splin
author_rank: Frequent Contributor
timestamp: October 19, 2019, 12:33:00 am
content: Datasheets for SMD inductors don't seem to show LF performance below 100kHz or more, so how susceptible are they to coupling in 50/100Hz magnetic fields from nearby mains or rectified mains wiring?Is it reasonable to assume that the core permeability, and thus inductance, don't change significantly at low frequencies for typical ferrite bead inductors below 1uH? I'm referring to inductors with multi-turn winding, not the ferrite beads threaded onto a wire.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 19, 2019, 05:52:54 am
content: So which is it, ferrite bead, inductor and multilayer or wound?All different things -- ferrite bead chips are always multilayer and saturate easily; ferrite beads (various styles, wound) saturate somewhat less easily but AFAIK always at some fraction of rated current. Inductors come in multilayer or wound types, the former evidently use a low-mu or distributed gap material while the latter use a formed shape with gap built in.- The enclosed types (multilayer, composite, molded, shielded) have good shielding, so that the susceptibility isn't much greater than an equivalent length of wire.- "Semi shielded" types usually have some variation of a bobbin core, so the external field coupling drops off quickly with distance (relative to the height of the bobbin). It's a dipole, but it's small?- Unshielded types are usually rod or solenoid variants and are ordinary dipoles along the axis.- Toroids are okay, usually having one equivalent loop turn (and corresponding wide dipole) due to the winding going around the toroid itself. This is negligible if there are a lot of turns on the core, and can be canceled out if the winding doubles back on itself. Few-turns toroids have further inhomogeneity due to the relatively large spaces between turns (each loop looks like a dipole, so the whole thing looks like a (n+1)pole..).HTHTim

author: splin
author_rank: Frequent Contributor
timestamp: October 19, 2019, 04:16:10 pm
content: Quote from: T3sl4co1l on October 19, 2019, 05:52:54 amSorry, should have been more specific - I was referring to 0402 or smaller parts. The lowest cost parts seem to be multi-layer ferrites such as the 220nH Taiyo Yuden HK1005R27J-T. I see that the more expensive LK series, such as the LK10051R0K-T, datasheet explicitly states:QuoteThe HK datasheet doesn't include that statement though so is that just an omission from the DS? Are all such multilayer ferrite chip inductors inherently shielded? Both types are listed as unshielded by Digikey but that means little.QuoteI'm not sure how saturation is particularly relevant here? The DC current will be very low or zero - the question was their susceptibility to induced interference from low level external magnetic fields from nearby transformers or wires.QuoteOK, that appears to be the answer, thanks.
SMD Marking - HELP PLEASE LOOK AT PICTURE -    LE Z019 - Page 1
Forum section: electronics / projects

author: jstarr
author_rank: Regular Contributor
timestamp: November 05, 2014, 07:00:30 pm
content: I have googled extensively without success. I am repairing a remote motor 12vdc controller that developed a short. It is a PIC microprocessor controlled MOSFET switching controller. It is made in Europe and has PCB designations that I think I understand.There is a two lead component looking like a big black diode and the PCB symbol says DZ1 and DZ2 so I figure these are zeners. I think the symbol is for ST and the marking says LE Z019.any help in id'ing this would be greatly appreciated.j

author: hamdi.tn
author_rank: Frequent Contributor
timestamp: November 05, 2014, 10:52:17 pm
content: my guess not zener but TVS SM6T6V8CAcheck this datasheethttp://www.farnell.com/datasheets/1761324.pdf
SMD mobile phone chinese speaker - Page 1
Forum section: electronics / projects

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: July 18, 2019, 03:50:16 pm
content: Hi,I want to find a very cheep source of SMD mobile phone speakers, I want to use them for toys, and I want them to be cheep and loud!Unfortunately lcsc has nothing to offer, I found some parts in mouser and digikey, but they are pricey for a toy under 3 USD total sellhere are some for your reference,https://www.mouser.com/ProductDetail/CUI/CMS-151135-078SP-67?qs=sGAEpiMZZMuTkJYgZlQcSSXjUNenqzceEziaKyMGZ2YzKBn%252BsbP4NQ%3D%3DSo I want to know if you happen to know some Chinese manufacturer, so I can get them reliably and cheaply!

author: Mechatrommer
author_rank: Super Contributor
timestamp: July 18, 2019, 04:43:10 pm
content: AliExpress: Phone MP3 Speaker?AliExpress: 13MM Round Tablet Phone MP3 Speaker?

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: July 18, 2019, 07:15:33 pm
content: Thanks for the links, though they are not that cheep, and also not SMDwhy we have a 0.03$ MCU but not a cheap Speakerwhere are you hiding yourself

author: ghost1325
author_rank: Contributor
timestamp: July 19, 2019, 05:30:21 am
content: https://item.taobao.com/item.htm?spm=a230r.1.14.19.566057bdToNB3Q&id=548051373517&ns=1&abbucket=20#detail😄about 1 $

author: ghost1325
author_rank: Contributor
timestamp: July 19, 2019, 05:47:15 am
content: https://www.alibaba.com/trade/search?fsb=y&IndexArea=product_en&CatId=&SearchText=SMD+SPEAKERmore cheaper smd speakers in alibaba!

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: July 19, 2019, 09:39:43 am
content: Thanks for the links,But I was seeking something in the order of 1RMB
SMD module spring loaded test connectors - Page 1
Forum section: electronics / projects

author: gertux
author_rank: Contributor
timestamp: December 25, 2017, 02:54:32 pm
content: Does anyone know where I can find the spring loaded test connectors like in this ESP-32 programmer ?Or even the correct name for these pins/header/socket ?Seems really handy for programming/testing all sorts of smd modules as these become more and more common.

author: ebclr
author_rank: Super Contributor
timestamp: December 25, 2017, 11:51:32 pm
content: http://www.yamaichi.co.jp/

author: gertux
author_rank: Contributor
timestamp: December 26, 2017, 08:42:18 am
content: Quote from: ebclr on December 25, 2017, 11:51:32 pmThe listed products seem promising but I didn't find a connector like the one in he picture. Maybe I overlooked it.

author: Kjelt
author_rank: Super Contributor
timestamp: December 26, 2017, 09:17:35 am
content: Looks like they are proprietary solutions.Digi sold their "bent" headers for a lot of $ but in the mean time also phased out:https://nl.mouser.com/ProductDetail/Digi-International/76002056You can make your own by using your own pcb place dual row header solder each column pin odd to even and bent the first row a bit outside.

author: RoGeorge
author_rank: Super Contributor
timestamp: December 26, 2017, 09:56:34 am
content: You can use this safety pins hack instead of pogo pins:https://hackaday.io/project/28439-esp-12-socket-adapter-solderless-flasher

author: 2N3055
author_rank: Super Contributor
timestamp: December 26, 2017, 10:26:50 am
content: disassemble RJ45 socket for gold plated spring wires..

author: gertux
author_rank: Contributor
timestamp: December 26, 2017, 11:39:30 am
content: Great tips for a DIY solution, but before I take that road I'll try to find an of-the-shelve solution.The RJ45 socket springs seem indeed better than a security pin. I also found a sping loaded connector for a dissected hard disk I could use:

author: jpanhalt
author_rank: Super Contributor
timestamp: December 26, 2017, 11:41:18 am
content: I have used the 3M Textool burn-in sockets for testing/programming SMD chips. They do not have the external pins as shown in your original post, but it is nothing to mount the Textool to a PCB with headers.https://www.digikey.com/en/pdf/3/3m/3m-textool-ph-lidded-socketsThe devices are relatively expensive from 3M, but you can find knock-offs much cheaper on eBay.

author: ebclr
author_rank: Super Contributor
timestamp: December 26, 2017, 12:34:16 pm
content: As an alternative solutionhttps://pt.aliexpress.com/premium/pogo%25252dpins.html?site=bra&g=y&SearchText=pogo-pins&tc=ppc&page=2&initiative_id=SB_20171226043326&prNum=0
SMD MOSFET ? - Page 1
Forum section: electronics / projects

author: r6502
author_rank: Regular Contributor
timestamp: June 01, 2023, 12:55:15 pm
content: Hello all,I'm looking for an SMD CODE, see attached photo and and Id - Vds diagram taken wit Peak Atlas DCA75proIt seems to be a MOSFET, N channel. Pinning ias also attached.Any informations welcomeThanks Guido
SMD pad size based on soldering method... - Page 1
Forum section: electronics / projects

author: alank2
author_rank: Super Contributor
timestamp: April 24, 2014, 12:45:54 pm
content: Hi Everyone,Most of my experience in through hole, but I've done some SMD soldering (by hand) and am looking to do more SMD via reflow oven.What I have been doing was sizing pads based on this criteria:2mils on all sides except the side approached from the soldering iron which is 20milsIt has worked fine for hand solder the few SMD projects I've done, but for reflow what is ideal? What do you use?Thanks,Alan

author: 8086
author_rank: Super Contributor
timestamp: April 24, 2014, 12:47:17 pm
content: I use IPC standard footprints or whatever the datasheet specifies.

author: Richard Head
author_rank: Frequent Contributor
timestamp: April 24, 2014, 01:22:14 pm
content: Me too. Also IPC standard or datasheet footprint. Never had a problem yet.

author: alank2
author_rank: Super Contributor
timestamp: April 24, 2014, 02:01:44 pm
content: Thanks guys, it looks like the IPC document is not freely available, but there is some sort of tool that has the footprints that is. Is this true?Thanks,Alan

author: zapta
author_rank: Super Contributor
timestamp: April 24, 2014, 03:03:05 pm
content: Quote from: 8086 on April 24, 2014, 12:47:17 pmSame here, with one exception. I was using a small resonator where the recommended pad was too small to hand solder and when I enlarged the pad the stencil allowed too much solder paste, almost shortening to the case. I ended up using the larger pad but with smaller smd cutout so I can can hand solder and use stencils.

author: Niklas
author_rank: Frequent Contributor
timestamp: April 24, 2014, 06:47:18 pm
content: Quote from: alank2 on April 24, 2014, 02:01:44 pmHave a look at this free IPC viewer:http://www.pads.com/downloads/lp-viewer-download/

author: calexanian
author_rank: Super Contributor
timestamp: April 25, 2014, 04:53:36 am
content: Consider a hot air station. I find a hot plate and a hot air station to be better and nearly as fast, if not faster than a home made reflow oven. Also IPC standard footprints here as well. Just the standard one in eagle works for me.

author: mrflibble
author_rank: Super Contributor
timestamp: April 25, 2014, 05:33:19 am
content: Quote from: calexanian on April 25, 2014, 04:53:36 amAnother vote for the hot plate + hot air method. Preheating the pcb makes it totally easy.

author: alank2
author_rank: Super Contributor
timestamp: April 26, 2014, 07:38:23 pm
content: I checked out the viewer, but how do you know which one to use? There are three libraries, least, nominal, and most. Then looking for a 20 pin soic 0.3" width I find 10 different land patterns! 4 of the 10 are one JEDEC standard, 2 are another, and then 4 don't have a standard.
SMD part ID help - Page 1
Forum section: electronics / projects

author: DTJ
author_rank: Super Contributor
timestamp: September 14, 2017, 08:40:44 am
content: Help!I'm trying to identify an IC used in a charger circuit.Its a SOT-23 5 pin package that is marked SNFRDH.I've tried searching the various lists and data bases for this marking and parts of the number without any success.Anyone got any ideas?Thanks.

author: amyk
author_rank: Super Contributor
timestamp: September 14, 2017, 09:28:15 am
content: NCP301LSN25T1? That one is in the package and marking is SNFxxx.

author: DTJ
author_rank: Super Contributor
timestamp: September 14, 2017, 10:49:09 am
content: Wow amyk - I think you're spot on. How did you know or find that? I'd been searching all afternoon. Thanks.I've also been trying to work out what these are as well (I don't want to wear out my welcome but I'm not having luck finding them...)I think a transistor SOT23 - 6 pin that is marked "TY" with a "Z" at right angles on the right hand side.And....What I think is some form of IC in a SOT23 - 5 pin package marked "28S".Thanks.
SMD Passives - Reel-to-Reel vs same-reel variance? - Page 1
Forum section: electronics / projects

author: rt
author_rank: Regular Contributor
timestamp: November 12, 2015, 01:06:53 pm
content: Example: If I use 10 x 10R (5%) resistors in parallel rather than a single 1R am I likely to see much improvement in % accuracy towards to nominal value?Or will neighboring components on the reel have a systematic offset typical of that batch? i.e. if one component is actually 10.5R will it's neighbours on the reel be more likely to cluster around 10.5R than be randomly scattered around 10R?Thanks,rt

author: free_electron
author_rank: Super Contributor
timestamp: November 12, 2015, 01:10:07 pm
content: Try it ...

author: matseng
author_rank: Frequent Contributor
timestamp: November 12, 2015, 02:12:09 pm
content: EEVblog #216 - Gaussian Resistor Redux -
SMD prototyping - Page 1
Forum section: electronics / projects

author: MaxFrister
author_rank: Regular Contributor
timestamp: February 18, 2018, 05:31:11 am
content: I've finally been forced to join the modern world and work with SMD parts. For bread-boarding I've been soldering parts to pcb carriers and then soldering .1 headers to the pcb.This has worked okay until I tried to install one of these into a dip socket. The .1 headers are too large. It seems like a fine-wire header is required.I saw these on ebay. Can anyone tell me what the headers are called and/or a supplier for them?(https://www.ebay.com/itm/2PCS-SOP8-SO8-SOIC8-SOT-to-DIP8-adapter-PCB-convertor/323009796523)

author: tooki
author_rank: Super Contributor
timestamp: February 18, 2018, 07:16:08 am
content: Those are machined headers. Easy to find on eBay under that name. I use them for just that kind of application.

author: DaJMasta
author_rank: Super Contributor
timestamp: February 18, 2018, 07:28:07 am
content: For what it's worth, the normal square headers should fit fine in a dual wipe socket - maybe not in the circular machined socket tops, but they do fit in others (though they may reduce the lifetime of it, since it's a right fit). the square headers also fit fine in breadboards, so the early prototyping phases they should still suffice for.

author: carlz0r
author_rank: Newbie
timestamp: February 18, 2018, 04:58:43 pm
content: As blueskull said, they are preci-dip headers. You can get them fromdigikeyamong other places.

author: KhronX
author_rank: Frequent Contributor
timestamp: February 20, 2018, 07:02:18 pm
content: ... Or if you can spare the height, just go with 0.1" pin headers, and use 0.1" socket headers to plug those into?

author: ZomBiE80
author_rank: Contributor
timestamp: February 21, 2018, 10:46:16 am
content: Those Preci-dip headers are originally meant for stacking PCB's, if anyone might think. (seems kinda obvious.)
SMD PTC Fuse for 24 VDC - Page 1
Forum section: electronics / projects

author: Alinik
author_rank: Contributor
timestamp: July 18, 2023, 11:36:28 am
content: Hello,I am designing a new version of a PCB board with a microcontroller to drive two 24 V DC brushed motors, and I am looking for a self-resetting PTC SMD fuse for a 24 VDC supply line and max 2.5 A. The current spikes present upon activation of the motors can be up to 3 A for a maximum duration of 80 ms (this current refers to that read on the power supply when a motion command is sent to the motors). I am currently using component 0154003.DR (https://mou.sr/43iZNvz) but would like to replace it with a self-resetting fuse. I have identified component 2920L150DR (https://mou.sr/3O5OHp7) (Vmax 33 V, Ih 1.5 A, It 3 A) but would like to be sure it will fit.In general for the fuses I know that:the hold current (Ih) is the maximum current you can pass through, and guarantee the device will not trip over the specified temperature range;the trip current (It) is the value where a maximum time-to-trip is characterised. Any current over this value is guaranteed to trip the fuse, within the specified temperature range.Any current in between may or may not trip the device depending on environmental temperature, current, component variation and how long its had the current passing through.The current drawn by the motors is then limited internally through the firmware on the microcontroller that stabilizes it below 1 A, so I think component 2920L150DR may be okay.

author: temperance
author_rank: Super Contributor
timestamp: July 20, 2023, 03:00:36 pm
content: Fuses are all about heat.Check if the fuse can hold the required current over the intended temperature range because the trip time and the hold current go down with increasing temperature or way up at lower temperatures. Does the PCB itself heat up,...Something to read for you to make proper decisions:https://m.littelfuse.com/~/media/electronics_technical/application_notes/resettable_ptcs/littelfuse_polyfuse_ptc_selection_guide_application_note.pdf
SMD Reel Cataloging / Organization Software Suggestions - Page 1
Forum section: electronics / projects

author: Omikron
author_rank: Contributor
timestamp: April 29, 2020, 09:49:54 pm
content: Ahoy Folks!I have somewhere between 60 and 120 reels of random components, mostly passives, that I've inherited from a lab that closed up shop, and I'm trying to figure out how to keep inventory.A spreadsheet is one option, but seems really clunky. I assumed that there would be some purpose-built software for cataloging components, part numbers, and counts, but I've been unsuccessful in finding such software online.Does anyone have any suggestions on how to proceed with cataloging the data? Right now the parts are fairly unusable because it's very hard to see what's what. Ideally I want some software that tells me at a glance if I have something in stock, and what location it's in.
SMD resisters for triac circuit instead of true hole - Page 1
Forum section: electronics / projects

author: cdwijs
author_rank: Regular Contributor
timestamp: October 06, 2014, 11:08:35 am
content: Hi All,I am routing a 230V PCB with a triac in it. This triac is fired from an opto-triac. The resistors are standard 1/4W models, and I use 2 of those in series to cope with the voltage. Those true hole resistors are a pain to route, as I need 3mm clearance on both side of the PCB to prevent arcing. Therefore I would like to use SMD resistors. What size is the minimum for this application? I guess the smaller ones (0805/1206) are too small to cope with the voltage.What are your thoughts on this? For reference I have attached the schematic.<edit> What voltages can I expect between M1 and G of a triac? When the triac is fired in Quadrant1, (MT1=0, MT2=+,G=+), I expect only about one volt, but I can't figure it out for the other quadrants. If that voltage is very low, I can use a small resister there.Kind regards,Cedric

author: cdwijs
author_rank: Regular Contributor
timestamp: October 06, 2014, 12:10:57 pm
content: Hi all,In the datasheet of the triac, I see Vgt (gate trigger voltage) is max 1.3V in all quadrants. After the triac has been fired, the voltage between MT1 and MT2 is 1.5V. Is it save to say the resister between the gate and MT1 only has to be rated for 1.3V, so a 0805 resister would be sufficient?Kind regards,Cedric

author: nsayer
author_rank: Regular Contributor
timestamp: October 06, 2014, 01:21:57 pm
content: A bigger concern would be potential power dissipation. The 0805s I buy typically are 1/8 watt. But it's probably alright.Of a bigger concern to me is the lack of a snubber. That's ok as long as you're using a purely resistive load. I've done some work with triac circuits recently and even the snubberless variety can sometimes have false transients if not snubbed. Additionally, the driver triac itself *also* needs to be snubbed.Here's what I came up with for my application. The triac I used was not designed to drive a large load - it's intended to be a contactor driver circuit. It allows a contactor to replace a DC relay.
SMDs on an Eurocard - how close is too close to a connector - Page 1
Forum section: electronics / projects

author: daqq
author_rank: Super Contributor
timestamp: October 14, 2015, 09:34:40 am
content: Hi guys,I've read that it is generally a good practice to not place brittle SMD components (namely MLCC caps) close to things that can undergo mechanical stress (connectors, mounting holes).Assuming an Eurocard style board (160mm x 100mm x 1.6mm) with a DIN connector to a backplane on one 100mm end, what would be a safe distance from the connector to start placing SMD components? As I understand it, most of the potential mechanical stress would be around the screws that connect the body of the connector to the device.Thanks,David
Smith Chart - Page 1
Forum section: electronics / projects

author: bostonman
author_rank: Super Contributor
timestamp: February 08, 2023, 04:12:34 am
content: Although it's been many years since I learned about Smith Charts, I've never understood how to look at one and understand if it represents a good circuit or a bad one.We just dotted the associated points and connected them, and, I've seen them in datasheets, but again, never grasp the concept of whether one is bad or good.Is there an easy way to tell?

author: pdenisowski
author_rank: Super Contributor
timestamp: February 08, 2023, 07:58:40 am
content: I don't think there's a simple answer to that question - "good" or "bad" depends on what you're trying to do.For example, in impedance matching, you're often trying get as close to the center of the Smith Chart as possible, while in load pull, you can use constant performance contours plotted on the Smith Chart to determine the optimum impedance for a given measured parameter (PAE, Pout, NF, etc.). There are lots of other examples.https://youtu.be/JtMeIdlEe40?t=961

author: xrunner
author_rank: Super Contributor
timestamp: February 08, 2023, 12:32:01 pm
content: Quote from: pdenisowski on February 08, 2023, 07:58:40 amExactly.Quote from: bostonman on February 08, 2023, 04:12:34 amSame answer as measuring a voltage with a DMM or inspecting a waveform with a scope. Is what they are representing on their screens "good" or "bad"? It depends on a lot of things that you have to take into account with the information you are looking at. So in a simple example if you are looking at what you believe is a "pure" resistance and you also see inductive reactance on the smith chart, then you must determine why it's showing that. Is that "good" (or in other words explainable) because the resistance leads are presenting inductive reactance, so it's what you should expect - it's acting as it should be in this circumstance. Or perhaps it's a SMD resistor and the resistance element is poor, so in that case you know the result is "bad"?

author: bostonman
author_rank: Super Contributor
timestamp: February 08, 2023, 04:08:02 pm
content: Good points, I hadn't thought about that aspect before posting my question.Would I have been better off asking whether a large circle is more/less resistive or inductive? I mean, if a hundred Smith Charts were in front of you, and you wanted to pick one based on a specific criteria, could it be done easily enough?Maybe a 50ohm load to use a practical example.

author: pdenisowski
author_rank: Super Contributor
timestamp: February 08, 2023, 04:21:51 pm
content: Maybe this would help? (It's the most-liked video on the R&S YouTube channel)
Smoke detector sensor - Page 1
Forum section: electronics / projects

author: ricko_uk
author_rank: Super Contributor
timestamp: September 27, 2020, 09:25:15 pm
content: Hi,I read some smoke detectors emit weak radiations, does anybody know if this smoke detector sensor does?https://www.shawcity.co.uk/oem-sensors-pdfs/ecosure2e.pdfThank you

author: bdunham7
author_rank: Super Contributor
timestamp: September 27, 2020, 10:30:23 pm
content: No, that's a CO detector, not a smoke detector.

author: ChristofferB
author_rank: Frequent Contributor
timestamp: September 27, 2020, 10:35:41 pm
content: The data sheet said electrochemical, so nope. The smoke detectors in question is usually termed called "ionizing" or similar.

author: ricko_uk
author_rank: Super Contributor
timestamp: September 28, 2020, 01:17:33 am
content: oops... you are right.So none of the CO2 detector types emit radiations of any type?Also for the smoke detectors how do I know if it is emitting or not?Thank you

author: james_s
author_rank: Super Contributor
timestamp: September 28, 2020, 01:47:39 am
content: Quote from: ricko_uk on September 28, 2020, 01:17:33 amIt will say it is an ionization type, and there will be a label on the sensor with a radiation symbol. It doesn't matter though, unless you disassemble the unit there is no significant amount of radiation emitted. The normal background radiation is so much higher that you'd need an extremely sensitive instrument to measure anything at all from it. If you do disassemble the sensor you can detect some radiation with a gieger tube if you hold it right up to the americium button.
[Project] SmokSensor air quality mesh sensor  - Page 1
Forum section: electronics / projects

author: stachu
author_rank: Newbie
timestamp: July 26, 2018, 07:39:16 pm
content: HelloI would like to present my project that I have been creating for two years.The project is research and development and is based on bots, analyzes, scientific publications and, of course, many tests.Air quality is definitely a very important topic, but unfortunately I was not satisfied with the relationships that are offered on the market usually either expensive or based on at most fifth generation sensors that have some disadvantages.I am looking for a person to help me create a map of sensors.If anyone is interested please contact me.I using dust sensor 7th generation (PM2.5 and PM10), pressure, temperature and humanity sensor.Sensor send request for server and updating date.I living in Cracow unfortunately we have the worst Air quality in europe but I have the best area for testing.The history in my project is in my FB fan pagehttps://web.facebook.com/smoksensor/Below a list of measurements from the sensor (right) and from a public air monitoring station (left)Average daily dose of dust PM2.5I would like the sensors to look as below but the housing is too expensive for me,I consider a slightly different design and printing on a 3D printer because it finances the project itself.Final PCB for projectRegards
Smooth rotary encoder? - Page 1
Forum section: electronics / projects

author: ataradov
author_rank: Super Contributor
timestamp: July 15, 2015, 06:30:44 am
content: I'm trying to locate a rotary encoder that has no sensible notches and has a damped action instead. Like a trigger level knob on the oscilloscope would have, for example.How they are called? I seem to only find standard ones with sensible fixed positions.

author: helius
author_rank: Super Contributor
timestamp: July 15, 2015, 06:35:54 am
content: Bourns PEC11R-40-*

author: ataradov
author_rank: Super Contributor
timestamp: July 15, 2015, 06:43:13 am
content: Ok, so it looks like what I'm looking for is "no detents". Too bad there is no a group name for such encoders. For this application I'm looking more at "$5 for 10pcs ebay from China" kind of a deal, not the Bourns price.

author: Jeroen3
author_rank: Super Contributor
timestamp: July 15, 2015, 06:50:26 am
content: Special parts come for special price.You can use rotary encoders for machinery, they'll have a constant torque.

author: senso
author_rank: Frequent Contributor
timestamp: July 15, 2015, 08:28:32 am
content: I'm pretty sure both Mouser and Digikey allow you to search for encoders with or without detents.

author: Melt-O-Tronic
author_rank: Frequent Contributor
timestamp: July 16, 2015, 04:04:30 pm
content: DigiKey currently shows 227 types of non-detent rotary encoders in stock, plus 2,000 more variants not in stock.http://www.digikey.com/product-search/en?FV=fff4001e%2Cfff80033%2C6280002&k=encoder&mnonly=0&newproducts=0&ColumnSort=0&page=1&stock=1&quantity=0&ptm=0&fid=0&pageSize=25

author: platone58
author_rank: Newbie
timestamp: July 26, 2015, 02:05:56 pm
content: www.ams.comAS504010Bit 360° Programmable Magnetic Rotary Encoder

author: Richard Head
author_rank: Frequent Contributor
timestamp: July 27, 2015, 01:09:03 pm
content: The Bourns PEC11 range is one of the cheapest encoders. It's certainly not pricey by any standard. I use it in an industrial product I manufacture and its reliability is not fantastic.
Smoothing ac signal after level shift - Page 1
Forum section: electronics / projects

author: anishkgt
author_rank: Frequent Contributor
timestamp: March 25, 2018, 02:47:58 pm
content: Hi All,i am trying to sample the ac signal after level shifting with an arduino just to read the voltage. The ON time is very short ranging from 10ms to 500ms. This is part of an spot welder project where by tapping two points on the secondary i get an AC signal. With the circuit attached the voltage is shifted in the dc range.I wish to know if the circuit can be enhanced in any way to have it smoothed out and also have the dc signal follow the AC.

author: MasterT
author_rank: Frequent Contributor
timestamp: March 25, 2018, 03:18:03 pm
content: DC doesn't follow AC because you have LPF. Reduce your circuits down to 3 resistors and a cap, right side image:

author: anishkgt
author_rank: Frequent Contributor
timestamp: March 25, 2018, 03:21:09 pm
content: Thank you.That is there to filter any high frequency that may arise during a spot weld. here the opamp is used to sense the voltage during spot weld and with ohms law determine the Current.

author: anishkgt
author_rank: Frequent Contributor
timestamp: March 25, 2018, 03:23:08 pm
content: attaching the LTspice

author: anishkgt
author_rank: Frequent Contributor
timestamp: March 25, 2018, 03:30:35 pm
content: Quote from: MasterT on March 25, 2018, 03:18:03 pmI've tried that as well since the ac voltage is in mV it would not be visible at all at the output.

author: anishkgt
author_rank: Frequent Contributor
timestamp: March 25, 2018, 03:31:30 pm
content: here is the scope view
SMPS - Page 1
Forum section: electronics / projects

author: Eltock
author_rank: Newbie
timestamp: October 29, 2020, 01:59:38 pm
content: Hi. i need a diagram over an smps, the input set to 9V from an 9V battery to +5V/500mA and -5V/200mA on the output, and i use an mc34063a? could anyone help me??

author: madires
author_rank: Super Contributor
timestamp: October 29, 2020, 02:57:22 pm
content: A standard 9V battery isn't able to deliver that much power.

author: Eltock
author_rank: Newbie
timestamp: October 29, 2020, 03:05:13 pm
content: i am all new in electronic. the thing i cant figure out is det circuit that comes after the mc34063a where the output to +5v and -5v is

author: madires
author_rank: Super Contributor
timestamp: October 29, 2020, 03:42:49 pm
content: You'll need two buck converters, one for +5V and an inverting one for -5V.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: October 29, 2020, 04:11:13 pm
content: First, If you pull so much current out of a 9V battery, it will be depleted pretty quick. Probably within an hour (Guess, have not bothered to look up energy content of 9V battery)You can use the mc34063, but it is a very old chip and has low efficiency, (which puts more strain on your battery). So I advise to use a more modern SMPS circuit.One advantage of the mc34063 though, is that it can be used in different configurations, including inverting. So you can configure a mc34063 to go from +9V to -5V directly.Another option is to use a toroidal core for the inductor, and then wind a 2nd winding over it and use it as a transformer. (and then use a diode and capacitor for single wave rectifier. This is not ideal though, as the secondary voltage is not well regulated. An advantage is that this voltage is floating.Some hints for further reading:There is a lot written about SMPS circuits.The datasheet of the mc34063 is quite good, as it has calculations for component values in each configuration.Another document worth reading is "switching regulators for poets", which is a PDF from one of the famous guys from the early days of semiconductor circuits.
SMPS and resistor power ratings - Page 1
Forum section: electronics / projects

author: kizzap
author_rank: Unknown
timestamp: January 18, 2013, 01:55:46 pm
content: This is probably going to be a stupid question, but then I guess that any question not asked is the stupidest questionI've been watching the SMPS design blog (#110) and wasn't quite sure on the calculations on the power rating that Rsc will need. Am I correct in assuming that it will simply be P=Ipk^2 x R?Thus if a circuit I am designing has a R of 0.5 ohm and an Ipk of 0.6A the minimum power rating I would need would be 0.18W? obviously preferring higher, say .25W or .5W?Or am I missing something here?Thanks-kizzap

author: Niklas
author_rank: Frequent Contributor
timestamp: January 18, 2013, 02:44:49 pm
content: Have a look at the datasheet formulas at 11:28. Rsc is 0.3/Ipk(switch) for all three modes and Ipk(switch) varies with the selected mode. The power rating of the resistor is probably a bit lower than R*Ipk(switch)^2 as the current wave form is triangular and Ipk(switch) is the top value. Usually you see the coil current as Iaverage+Iripple, where Ipk(switch) is the maximum.(1) R = 0.3 / I(2) P = R * I^2Substitute R in (2) with R in (1)(3) P = (0.3 / I) * I^2 = 0.3 * IIf you calculate the resistor power using Ipk instead of Iaverage you will get som extra safety margin. A 0.25 Watt resistor should do the job, just make sure that it has low series inductance. Wire wound and sometimes also metal film resistors can cause problems. Carbon film or carbon composition are better alternatives.

author: rbola35618
author_rank: Frequent Contributor
timestamp: January 18, 2013, 08:32:46 pm
content: The correct current should be rms, not average current. This is more true if the dc voltage is pulsating or swinging negative.P=Irms^2*resistorRB