hybridfree/eevblog-posts huggingface dataset:
Source for high quality (robust) RGBW SMD LEDs? - Page 1
Forum section: electronics / beginners

author: Cameron
author_rank: Newbie
timestamp: November 28, 2024, 10:48:29 pm
content: Hi all, new to the forum, let me know if this isn't the right place for this question.I'm working on a PCB with a range of addressable LEDs in specific locations for an outdoor decoration. I intend to drive it with an ESP32 and WLED. There will be about 140 LEDs per part, so I will be getting the boards assembled by JLCPCB. The boards will be 12V, kept outdoors for extended periods in the summer, and accessing them will be a pain so reliability is a key priority for the part selection. The LEDs should be RGBW with a warm white, probably in a 5050 package.Right now I'm looking at using external WS2814 ICs as the driver for the individual LEDs, mainly due to the dual data line, RGBW, WLED operability, 12V and availability on the JLCPCB parts library. I'm also thinking having the IC and the LEDs separate rather than integrated may help slightly for heat management.My challenge now is finding decent RGBW capable LEDs. The options I'm finding on digikey are more than $1 each, which is way too much. I'm finding more reasonable options on the JLCPCB parts library, but as all the datasheets are in chinese and I don't know the companies I'm not sure which options are likely to be more robust. It's also a massive pain searching on the JLCPCB parts library.Does anyone know any good sources for LEDs for outdoor applications which can be used with JLCPCB assembly? Names of companies with a good reputation?I'm also open to using an integrated LED and driver chip such as SK6812, but I haven't been able to find any on the JLCPCB parts library in 12V and warm white RGBW. Anyone with some suggestions there?Thanks!

author: BennoG
author_rank: Frequent Contributor
timestamp: November 29, 2024, 10:02:19 am
content: The quality of the leds does not matter much as long as you don't overdrive them.your biggest problem will be moisture. (rain fog ...)At 12VDC this will cause a lot of problems with oxidation. So potting or other kind of water resistant measurements should be taken.My experience is you will fail at the last part in about 90% of the times. (unless you mount them indoors)Benno

author: Cameron
author_rank: Newbie
timestamp: December 01, 2024, 03:29:16 pm
content: Thanks! I'm still a bit lost in all the manufacturers, hard to tell regarding other factors like how broad the white channel spectrum is (for light quality etc) with these chinese datasheets.Waterproofing I'm less worried about as that's handled by my friend who's been doing decorations in coastal environments for the last 10 years or so, he'll have the headache of tropicalising it all, but ideally I can make his life as easy as possible.

author: themadhippy
author_rank: Super Contributor
timestamp: December 01, 2024, 04:07:35 pm
content: QuoteIf the rgbw does that matter as you can chuck a bit of extra red or blue in with the white
Source for Linear Systems parts, to UK? - Page 1
Forum section: electronics / beginners

author: guymo
author_rank: Regular Contributor
timestamp: May 27, 2021, 10:12:55 am
content: I'd like to get hold of some Linear Systems parts for some ideas I'm toying with. In the past I have bought from micross.com with no issues. Micross no longer has a direct purchasing option on their web site and instead you have to email for a quote; the response I received indicated a minimum order quantity of 50 for the parts I was asking about (dual JFETs). I don't really need 50 LSK489s for my experiments...Are there any other sources for their parts that will ship to the UK and would sell 5 or 10 pieces at a time? I'd expect the unit price to be higher than from micross but presumably not as much as buying 50...

author: Terry Bites
author_rank: Super Contributor
timestamp: May 27, 2021, 02:31:52 pm
content: https://store.nacsemi.com/Products/Detail?part=LSK489-SOIC&stock=LIS000000001347&Mfr=LINEAR%20SYSTEMSBuy on line MLQ=1

author: Gyro
author_rank: Super Contributor
timestamp: May 27, 2021, 06:10:25 pm
content: Quote from: Terry Bites on May 27, 2021, 02:31:52 pmThey appear to be in Florida. I don't see any stock outside the US in the 'Delivery' tab or shipping cost to the UK.Do you have any experience of using them and their international shipping costs?EDIT: Here's a fairly recent sourcing thread...https://www.eevblog.com/forum/projects/found-a-source-of-linear-systems-fets-and-pico-amp-diodes/

author: guymo
author_rank: Regular Contributor
timestamp: May 27, 2021, 06:20:41 pm
content: Quote from: Gyro on May 27, 2021, 06:10:25 pmThanks. The minimum order of £25 reported in that post matches my previous experience buying from there, but as I say, they’re quoting MOQ of 50 pieces now, which will be £300 plus VAT. Not sure why that has changed.

author: guymo
author_rank: Regular Contributor
timestamp: May 27, 2021, 06:28:40 pm
content: Quote from: Terry Bites on May 27, 2021, 02:31:52 pmThanks. It looks like they do indeed ship to the UK. I’ll investigate some more and confirm.

author: Gyro
author_rank: Super Contributor
timestamp: May 27, 2021, 06:29:45 pm
content: Sorry, I didn't notice that it was Micross.

author: floobydust
author_rank: Super Contributor
timestamp: May 27, 2021, 06:50:06 pm
content: It's unfortunate these small semi manufacturers aren't available at big distributors such as Mouser, Digi-Key, Farnell etc.It's the death of them going through massively overpriced boutique distributors, the parts end up far too expensive. They'd sell more without the fat middleman.Literally had to get a guy to drive in Texas to a boutique distributor and get my JFETs. Including the exchange rate, it hurt.
Source for switches for detecting tapes, cd tray position, etc - Page 1
Forum section: electronics / beginners

author: fabiodl
author_rank: Frequent Contributor
timestamp: May 02, 2022, 08:59:20 am
content: First of all, what is the name of this kind of switches?https://eshop.avr.gr/en/rsh1a90zThey usually come in a clear plastic housing, not shown in this pic. They are used to detect tape presence/recordability etc. Sometimes they are used in CDs to detect when the tray is closed/ fully opened.Do you know any source for them?They often oxidize. Using contact cleaner/sand paper usually helps for few months, but finding nos would be ideal.

author: RoGeorge
author_rank: Super Contributor
timestamp: May 02, 2022, 09:17:38 am
content: Contacts might have thin layers of various metals, so don't use sandpaper or other abrasives.I used to use pencil eraser, that will only erase the oxides and don't file out the metal. Cut a thin sheet out of a pencil eraser, insert it between the contacts and gently erase the oxides. Then brush away any pencil-eraser debris.

author: BreakingOhmsLaw
author_rank: Frequent Contributor
timestamp: May 02, 2022, 01:03:41 pm
content: That's called a Spring Lever Contact.One warning about cleaning them: They may be made of copper-beryllium. Beryllium is highly toxic, do not use sandpaper on them. Inhaling the dust is bad news.Better use good old acidic contact cleaner.Sourcing them is a PITA. Most are long out of production and there were hundreds of them. Old TV repair shops may have them in stock if you can still find one.

author: fabiodl
author_rank: Frequent Contributor
timestamp: May 15, 2022, 07:38:47 am
content: Thank you. I will try with the pencil eraser, nice idea!Unluckily I have no old TV repair shops around
Source for very small headers? (twice the density) FOUND - Page 1
Forum section: electronics / beginners

author: cdev
author_rank: Super Contributor
timestamp: September 03, 2017, 11:48:34 pm
content: where can I get some very small headers, to make a breakout board of sorts for a very small device?It basically is "half size" meaning half the distance of regular headers.This is basically a hack to update an old wireless access point's internals with more modern hardware- because it seems a shame to throw it away- so, keeping the case and jacks, antenna, etc..

author: aandrew
author_rank: Frequent Contributor
timestamp: September 04, 2017, 01:34:29 am
content: What's a "regular" header? 0.100"?0.050" headers exist, as do the metric 2.54, 1.27, 1.0mm and so on. Take a look at Digi-Key, we can't do your homework for you.

author: buck converter
author_rank: Regular Contributor
timestamp: September 04, 2017, 02:24:43 am
content: They appear to be on eBay.

author: cdev
author_rank: Super Contributor
timestamp: September 04, 2017, 02:28:55 am
content: This is kind of similar to what I want to do.They arent available in small quantities for cheap.FOUND.. needed to specify "1.27mm" not "1.27 mm"

author: ebclr
author_rank: Super Contributor
timestamp: September 04, 2017, 02:31:57 am
content: you can chose from herehttps://pt.aliexpress.com/wholesale?catId=0&initiative_id=SB_20170903183118&SearchText=1.27mm+header

author: tooki
author_rank: Super Contributor
timestamp: September 04, 2017, 01:48:35 pm
content: Quote from: aandrew on September 04, 2017, 01:34:29 am2.54mm and 1.27mm are, canonically, .1" and .05" respectively.
Source of very thin hard plastic tubing? - Page 1
Forum section: electronics / beginners

author: Chris Wilson
author_rank: Super Contributor
timestamp: August 27, 2013, 12:22:14 pm
content: I want to make spacers out of thin plastic tube to space LED's off a PCB. The PCB will mount behind a metal front panel on short hexagonal stand offs. The LED's will be spaced off the PCB with their leads left about 20 mm long. I want to slip hard plastic tube over the leads, so when the inevitable happens, and someone presses on an LED where it protrudes through a front panel hole, it won't easily cripple the leads and it regress back inside the cabinet. I thought of Biro ink tubing, but am I missing a better and cleaner source? Thanks.

author: fcb
author_rank: Super Contributor
timestamp: August 27, 2013, 01:05:35 pm
content: very thin hard plastic tubing - surely an oxymoron.I've used plastic pcb spacers on LED's before (very cheap from Rapid), but not at 20mm, you could always look to something like 4mm air-tubing, thats pretty stiff but will have a large radius bend in it (which probably won't hurt at 20mm).I would consider light-pipes over SM LED's though. My favourite source:www.toby.co.uk

author: notsob
author_rank: Frequent Contributor
timestamp: August 27, 2013, 01:18:17 pm
content: you can also place a length of clean (no copper cladding - or etched off) FR4 vertically between the LED leads

author: cowana
author_rank: Frequent Contributor
timestamp: August 27, 2013, 03:09:55 pm
content: Why not go with a premade solution? It means you don't have to cut lots of tube to *exactly* the same length...http://www.toby.co.uk/content/catalogue/products.aspx?series=LED-xxCheers,Andy

author: jaxbird
author_rank: Frequent Contributor
timestamp: August 27, 2013, 03:53:43 pm
content: You could try some teflon (PTFE) tube, it's fairly rigid and likely what the ink tubes, you mentioned, are made of.

author: Chris Wilson
author_rank: Super Contributor
timestamp: August 27, 2013, 04:01:17 pm
content: The pre made spacers or light tubes look tempting, I have to say, plus with me being in the UK their source is convenient, too. I'll do some measurements....Thanks!

author: Paul Price
author_rank: Super Contributor
timestamp: August 27, 2013, 05:34:49 pm
content: I simple drill the holes for the LED's so they can be press fit and then apply a tiny swab of Alphacynacrylate (superglue) (just a tiny drop on the rear of the front panel holding the LEDs)and they stay strongly in place.
Source parts from 1688 / taobao via an agency - Page 1
Forum section: electronics / beginners

author: soFPG
author_rank: Frequent Contributor
timestamp: October 30, 2019, 03:39:27 pm
content: I am currently trying to source parts from 1688.com / Taobao and what I find happening is that a lot of parts on 1688.com are priced as 1 Yuan, 0.01 Yuan or 0.02 Yuan and the text in the description says that the buyer should get in contact with the seller to discuss the real price.The agency I am working with has the option to make them ask the seller about the real price - so I did that for several parts. And one 128kByte SRAM module was originally priced as 0.02 Yuan (which can't be true I know that) and the real price is 15 Yuan.I mean - WTF?Why would they do that. The sellers at 1688 / Taobao are just wasting everyones time - people from the agency who ask for the real price and mine.

author: I wanted a rude username
author_rank: Frequent Contributor
timestamp: October 30, 2019, 11:03:13 pm
content: If there are other, genuine listings, you can just ignore these fake ones. It is the same as listings on eBay with a price range (e.g. $1-$9 ... $9 being the thing you want and $1 being some unrelated piece of crap): they almost never have the lowest actual price, so you can scroll past them to the price you "expect" and start there.

author: soFPG
author_rank: Frequent Contributor
timestamp: October 31, 2019, 08:26:44 am
content: Thanks for your reply. Would you recommend to buy stuff from over there to make a bargain in general?

author: soldar
author_rank: Super Contributor
timestamp: October 31, 2019, 09:20:05 am
content: Quote from: I wanted a rude username on October 30, 2019, 11:03:13 pmI hate it when they do that but it is difficult to prevent it because they could be selling options of the same thing or just bait'n'switch. They could be selling marbles in lots of 5, 10, 20, 50, 100 or they might trick you by offering a lab PSU for $50 and a "lab psu power cord" for $5.

author: thm_w
author_rank: Super Contributor
timestamp: October 31, 2019, 11:49:27 pm
content: Yeah thats a waste of time, interestingly I have not experienced that yet, I avoided any <1 yuan items completely.One thing I did get caught by, every item I've purchased that was on "promotion" price was only valid for the first part. So if you buy two the second one is at regular price. Didn't understand why..

author: soFPG
author_rank: Frequent Contributor
timestamp: November 01, 2019, 02:33:20 pm
content: Just asked for 10 pieces of an item which was priced as 7.50 Yuan and it actually is now 12 Yuan - I don't get these fake sellers

author: thm_w
author_rank: Super Contributor
timestamp: November 01, 2019, 09:45:13 pm
content: Quote from: soFPG on November 01, 2019, 02:33:20 pmIf you have nothing better to do, you can just try to buy it and see what happens (if it is really listed as 7.50 each).I did have one seller ship the item, THEN say the price was wrong after the fact.. so they might get caught on their BS.I'm not sure how hard it is to go through a dispute via the agent though.
Sourcing a small lcd screen - Page 1
Forum section: electronics / beginners

author: carbon dude oxide
author_rank: Frequent Contributor
timestamp: July 30, 2013, 12:43:30 pm
content: Hello, i am having trouble sourcing some kind of lcd screen, it can be colour or just back and white but the only problem is that the physical size needs to be 27.5mm wide or slightly smaller and it needs to be between 35mm to 55mm long. Does anyone know any manufacturers which do this sort of size or a company tht can do custom sizes this small?It does need to be as high of a dpi a possible as the screen (if possible) would have a small bar code accross the bottom.Does anyone know anyher i could get something like this?

author: David_AVD
author_rank: Super Contributor
timestamp: July 30, 2013, 10:05:10 pm
content: Have you looked at the ePaper screens? I got a 2.7" kit the other week (haven't had time to play yet), but I'm sure you can get much smaller ones.

author: carbon dude oxide
author_rank: Frequent Contributor
timestamp: July 30, 2013, 10:22:04 pm
content: They look almost perfect for the use i need XD tere thin require very little power (only consumes when changing) and displays the last image even when there is no power. I have had a quick glance on google and so far cant find one small enough but i shall have a look in the morning

author: David_AVD
author_rank: Super Contributor
timestamp: July 30, 2013, 10:30:29 pm
content: I got my demo kit fromGlynover here. They have a 1.44" version. Not sure if that is small enough for your application.
Sourcing embedded displayport (eDP) panels - Page 1
Forum section: electronics / beginners

author: NotionalLabs
author_rank: Unknown
timestamp: November 18, 2014, 11:34:30 am
content: Hey all,I'm doing some research for a project that requires a display panel for a compact all-in-one mini-pc. I've identified a candidate small form-factor motherboard that meets the required spec:http://www.asus.com/us/Motherboards/Q87TCSM/specifications/- this mobo supports eDP and LVDS onboard connectors. I'd prefer to use eDP panels if possible as it appears much simpler than LVDS and can drive a higher resolution. Ideally I'd like around a 9" panel (the smaller, the better).The problem I'm having is that I can't seem to find anywhere that reliably stocks these panels - I've tried Mouser, Digikey, Farnell, and eBay without much luck. I'm new to sourcing this kind of thing, so if anyone can point me in the right direction I'd appreciate it.Thanks,Jim

author: ConKbot
author_rank: Super Contributor
timestamp: November 18, 2014, 01:36:55 pm
content: Not the most budget friendly, buthttp://www.adafruit.com/products/1751rediculously awesome resolution though.http://www.adafruit.com/products/1716is an adapter from the flat flex to DP (just wiring) and a driver for the backlight.There's the whole kit for the thing toohttp://www.adafruit.com/product/1652which had the driver board, and laser cut plexi to make a stand. Perhaps use the design as a guide/inspiration for whatever you do with the PC?If the 9.7 is too big, perhaps other products use eDP, and you can use replacement screens for them?

author: NotionalLabs
author_rank: Unknown
timestamp: November 19, 2014, 01:19:16 am
content: Ah, the venerable iPad Retina display! I'd love to use a display like this, but I think they have a 51-pin ribbon connector that isn't compatible with the 30-pin eDP connector on the motherboard.Since the signalling is the same, I wonder how painful it would be to create a 51-pin to 30-pin + backlight power connector cable/patch would be...Thanks for your response!Jim
Sourcing Specific Connector Contacts (For Original 203W Xbox 360 PSU) - Page 1
Forum section: electronics / beginners

author: BAM5
author_rank: Contributor
timestamp: January 19, 2018, 09:55:36 pm
content: Hi there,I've got a project where I'm building a custom PC and I've decided to power it with an old 203W xbox 360 PSU.Instead of chopping off the proprietary connector at the end of the PSU I've opted to make a more polished look by disassembling axbox 360 to slim xbox 360 power connector converter..Taking it apart I see that there are only 4 out of 6 power carrying contacts on the plug and I'd like to be able to add the 2 more, but I'm not sure where I can get these contacts.I've tried googling all sorts of terms but just find the standard terminal / blade crimp connectors. I found a site called TE Connectivity and manually searched through their power connector contacts catalog but couldn't find anything that looked like what I need.What is your process for finding parts like this? And if you don't mind, could you help me find these??Here are what the connector and contacts look like.And here are some dimensions pulled from the contacts.Height: 3mmWidth: 3mm (Not including stopper tabs)Length: 18mm (From end to end)Thanks for any help you can provide!
Sourcing these componant draws - Page 1
Forum section: electronics / beginners

author: carbon dude oxide
author_rank: Frequent Contributor
timestamp: September 09, 2013, 12:03:19 pm
content: Hello, i have been looking for a while now but i have been unable to locate any of these componant draws:There red and they interlock into eachother (in blocks of 8 small draws) does anyone know where i could buy some more of these componant draws?Im unsure where they came from as i bought these with componants inside on ebay. Any help on this would be very usefull thanks

author: nessatse
author_rank: Regular Contributor
timestamp: September 09, 2013, 05:59:59 pm
content: Sorry to be a spelling nazi, but the word is drawER, and componEnt. Spell checkers are free

author: carbon dude oxide
author_rank: Frequent Contributor
timestamp: September 09, 2013, 06:04:39 pm
content: I sent it from my iPhone and it did not say anything was wrong, I am sorry for not noticing.

author: pmcouto
author_rank: Unknown
timestamp: September 09, 2013, 06:56:27 pm
content: Hi carbon dude,Although not compatible with the ones you have, there is a Portuguese company who manufactures very similar drawers (www.suc.pt).I know that most of their production if for export, but I don’t know if they have any distributors in the UK…Regards,Pedro Couto
Sourcing transformers for 120V => 100V Buck Boost Transformers - Page 1
Forum section: electronics / beginners

author: Mikek400
author_rank: Regular Contributor
timestamp: January 09, 2016, 11:39:03 pm
content: I have an item that uses 100VAC 140W 50/60Hz.I would like to keep the transformer as small as possible so that it can fit inside the unit. And having a mounting bracket would be a plus too.I have built buck boost transformers but I don't know how you know how much power you can run through one.For example a 120V => 20V 1A transformer. Can you draw 1A through it at 100V in a buck transformer configuration?Was looking at this onehttp://www.ebay.com/itm/HC-Controls-Step-Down-Transformers-120V-to-24V-HCT-01P0AA00LP117-30VA-50-60-HZ-/252210900690?hash=item3ab8f0eed2:g:UGYAAOSwp5JWbODW

author: IanB
author_rank: Super Contributor
timestamp: January 10, 2016, 12:19:40 am
content: If your item draws 140 W at 100 V then it will pass a current of 1.4 A. If your buck transformer is bucking 20 V, then it will need to have a VA rating of about 20 x 1.4 = 28 VA to safely handle the load. Another way of saying this is that your transformer secondary should be rated for 1.4 A or more.

author: Mikek400
author_rank: Regular Contributor
timestamp: January 10, 2016, 01:25:35 am
content: Thanks for confirming. That's how I thought it worked.The other question is about a 120V to =>24V Transformer.I have made buck boost transformers using 100V =>24V transformers and it bucks roughly 20-24V.If I use a 120V => 24V transformer will the ratio be the same? I'd guess maybe not.TIA
Sourcing wire wrap wire - Page 1
Forum section: electronics / beginners

author: AussieBruce
author_rank: Regular Contributor
timestamp: February 10, 2023, 04:23:13 am
content: I've had trouble buying wire wrap wire for a while, the old days when it was always one standard gauge seem to be gone. My recent purchases had all suffered from problems including unexpectedly fine gauge or crappy metal - wraps with a tendency to break at the pin. Firstly, is there a 'standard' gauge for wire wrap wire? Secondly, can anyone suggest a source of good quality material in hobby quantities? Choice of colours would be nice but not essential.

author: WattsThat
author_rank: Frequent Contributor
timestamp: February 10, 2023, 06:01:09 am
content: Yes, 30 AWG is the standard size. The usual insulation is Kynar and the wire will be silver plated, not tinned.You can find plenty of 30 AWG wire from China for cheap but it is tin plated with PVC insulation which has a much larger outside diameter due to insulation thickness which makes for some issues with standard wrapping bits.You can find some decent stuff on eBay if you look for 30 AWG and Kynar together- this automatically becomes silver plated due to the higher temps required to apply the Kynar insulation.Not sure what’s available locally where you are.

author: lwatts666
author_rank: Unknown
timestamp: February 11, 2023, 05:04:41 am
content: Rockby electronics has precut/stripped packs in various lengths and some colour choices:https://www.rockby.com.au/SearchresSql_12.cfm?Searchkey=wire+wrap
Sovereign Garden Shredder fix help - Page 1
Forum section: electronics / beginners

author: Fiddle_er
author_rank: Contributor
timestamp: August 09, 2016, 07:34:59 pm
content: <IMG_20160810_080121332.jpg> Got this sovereign shredder wondering if anybody prepared to help me fix it?so far i pulled it a part physically checked to see if the motor would turn, and yes very very tight, normal ?i noticed the adjuster broken through the side case common fault appaerntly , anyway reckon i can fix that somehow.did some probing about with fluke dvm confirmed 240vac at back of plug (socket inside) did this because already checked fuse and the connector is a really bad fit and not sure making contact in the socket itself but all is ok there.then i tried to short out the wires i removed from the stop start switch but nothing happened ? it is getting hard to explain now i think i need to post some pictures that is if anybody interested.?thoughts ; it has a large capacitor , my theory here is vague at best but i recall some motors used cap for starting as they only 2 phase motor , i tried to sketch out cct dia but i am too thick to do that. also found a black box under the motor mount that i have absolutely no idea what it is ? thought at first owing to its position it was for factory testing, i think this item is not working as i believe i am a supply missing off oneside of switch , this is one of those power latching (hold on) switches, so the unit will not fire up on its own if power is cut or something?OK gone on a bit here that this be digested a while and see if i am lucky.cheers

author: Brumby
author_rank: Unknown
timestamp: August 09, 2016, 11:19:51 pm
content: Pictures would be nice.We don't even know if you're talking about a garden shredder or a paper shredder....If it has a large cap, then I'm guessing it's the former.

author: Fiddle_er
author_rank: Contributor
timestamp: August 10, 2016, 07:28:12 am
content: Thanks trying to add photos but dont know how to do it yet first attemt did not work. i am on mac computer and i dont see url just an IMG code?

author: BurningTantalum
author_rank: Frequent Contributor
timestamp: August 10, 2016, 07:35:11 am
content: The best and safest way to start is to trace the continuity through from the mains plug to the switch etc on the live and then the neutral, and also the continuity of the motor windings. This type of tool now has to have a No Volt Release type 'switch' to prevent it restarting after power is removed and then reconnected again with the on/off switch left on- not good if you have your mitts in the blades clearing a jam.My limited experience of the cheaper of these tools is that they are sometimes seized from new. There are plain steel bearings on the cutter shaft which are not lubricated on manufacture. When I worked in China they referred to grease as 'English Butter' and were not too keen on bothering with it.Does the motor hum at all?BT
SP3T slide switch schematic, how to know the pins? - Page 1
Forum section: electronics / beginners

author: VEGETA
author_rank: Super Contributor
timestamp: May 07, 2024, 06:40:21 pm
content: Hello,I want SP3T (or DP3T) slide switch and I found this one:https://www.lcsc.com/product-detail/Slide-Switches_SHOU-HAN-SS13D07VG2_C2681576.htmlit is nice enough for my low current (<1mA) needs, but I really struggle to know the actual pins, not only for this model but for others except those which explicitly point them.can you tell me from its datasheet which pin is the input or common and which are the 3 outputs?from what I understand, the 2nd pin from the left is the common one or input.

author: Rick Law
author_rank: Super Contributor
timestamp: May 07, 2024, 07:01:56 pm
content: You can tell on page 4 of the datasheet, upper right corner (top diagram) is the schematic diagram of the switch. It shows which pin is connect to which other pin based on switch position. The center pin (shown in dark bar) is the "source" and the other three are the target depending on switch position.

author: Kim Christensen
author_rank: Super Contributor
timestamp: May 07, 2024, 07:14:53 pm
content: Well, it is probably really a 3 position since they spec 2mm travel, there is 2mm between pins, but a 6mm slot.But the description says, "triple-pole/single-throw"...This is what I think it is:(EDITED)

author: Rick Law
author_rank: Super Contributor
timestamp: May 08, 2024, 05:11:25 pm
content: Quote from: Kim Christensen on May 07, 2024, 07:14:53 pmNo disagreement here. I looked at the datasheet and considered the description in error. The schematic on the datasheet clearly describes 3 position (throw) with a single pole.Personally, I prefer two poles. Pin layout is the same but in two rows one on each side. The second pole serve as extra anchor to the PCB and as backup electrically - two rows of pin hold the switch to the PCB better and if just one pole makes good connection that would be good enough. So 2pole is a bit more durable than 1pole.

author: VEGETA
author_rank: Super Contributor
timestamp: May 08, 2024, 10:14:27 pm
content: Quote from: Rick Law on May 08, 2024, 05:11:25 pmactually i opted for DP3T which is the only thing that can work for my application... to switch between 3 small batteries... 2 of them has negative going to ground but the third is not... it must go to li-ion protection circuit. if it was going to ground then SP3T could work.found many of those DP3T on LCSC for very cheap... current going through them is < 1 mA so it will be fine.

author: vu2nan
author_rank: Contributor
timestamp: May 10, 2024, 06:32:37 am
content: Here's the switching scheme.The sliding contact of the switch bridges the fixed contacts (terminals) 1 & C, C & 2 and C & 3 in positions 1,2 & 3 respectively.
Space-efficient way of current limiting output of a boost converter with TPS5534 - Page 1
Forum section: electronics / beginners

author: erwining
author_rank: Newbie
timestamp: August 12, 2025, 11:57:40 am
content: Hello everyone,I am looking for a space efficient way of limiting the output current of a boost converter. I am using the TPS55340 to boost from 3.3V to 32V. I need the maximum to be at around 20mA. What is the best space-efficient and most effective way? I already tried a TLV9351 and an NPN transistor to drive the FB pin, but that pin can only handle 3V, so I'd need two additional transistors and a 2.2V Zener Diode, which blows my footprint constraints.Do you have any ideas?

author: erwining
author_rank: Newbie
timestamp: August 13, 2025, 08:44:33 am
content: For anyone stumbling across this later:I solved it by using the 2 transistor top-side version of this thread:https://electronics.stackexchange.com/questions/352625/simplest-cheapest-fast-and-minimum-footprint-current-limiting-circuit-with-lowBe aware that the pass transistor needs to dissipate quite a bit of power, so choose a bigger package like SOT-223 and the sense can be smaller like SOT-23. Hope this helps. Simulated and verified above in LTSpice.

author: mtwieg
author_rank: Frequent Contributor
timestamp: August 13, 2025, 02:10:29 pm
content: If you needed to avoid the pass transistor, another method would be to add an external current feedback loop (injecting current into the COMP or FB pin when Iout exceeds some threshold). Getting both the current and voltage feedback loops to be stable might take some iteration though.

author: erwining
author_rank: Newbie
timestamp: August 13, 2025, 06:20:08 pm
content: Yeah I also thought about that, but as you said, it might take a couple more iterations. I need to work with TI components, which do seem to require PSpice to properly simulate, as a lot of the TINA-TI models just seem broken. I might try some other variations in future designs, for now I'll leave it at the 2-transistor solution.
Spare equipment  - Page 1
Forum section: electronics / beginners

author: alin_im
author_rank: Regular Contributor
timestamp: January 06, 2015, 10:23:29 pm
content: Hi guys,My name is Alin, I am a year 2 student at University of Huddesfield in United Kingdom at Electronical and Electrical Engineering , I am very passionate about what i do and i wanted to open a basic electronics repairing laboratory. The bad part is that i have about 150 Pounds to start my little lab. Do you know any good sites with low budget electronics (besides Ebay ) especially an oscilloscope or signal generator ? Or do you have any spare electronics equipment that you do not use or are broken ? I will pay for the shipping if you have and you want to send it. I would really appreciateHope to hear from you soon.

author: katzohki
author_rank: Frequent Contributor
timestamp: January 06, 2015, 11:36:24 pm
content: Why not eBay?Look for a used analog oscilloscope available at a electronics swap meet or something local. You should be able to find something available in your price range. My first 'scope was a 60MHz analog two channel that I bought for $40 (USD) at a ham radio swap meet.Build your first function generator. That will be the perfect way to test out your new oscilloscope! There are lots of free designs based on 555 timers or Exar chips that will be suitable. Pick one and just build it.

author: Wilksey
author_rank: Super Contributor
timestamp: January 07, 2015, 12:07:23 am
content: Speak to TopLoser and read this post:https://www.eevblog.com/forum/buysellwanted/fs-wellerpacemetcal-soldering-equipment/msg581802/?topicseen#msg581802
Spare set of test probes/leads ? - Page 1
Forum section: electronics / beginners

author: Russ
author_rank: Regular Contributor
timestamp: December 23, 2017, 10:54:35 pm
content: I picked up a spare set of leads for my Eevblog/Brymen 235. Do these ever go bad or malfunction? The spare set is identical to the set that came with the meter.Thanks

author: Electro Detective
author_rank: Super Contributor
timestamp: December 24, 2017, 02:39:55 am
content: They perform and look well made to meand should last if not abusedor driven over by a forklift...twicePerhaps Dave might consider dissectingtrashinga setLIVE ON YOUTUBEvs the Fluke equivalent standard leads

author: danadak
author_rank: Super Contributor
timestamp: December 24, 2017, 02:42:51 am
content: Over time, under use, leads do fatigue. Insulation ages, cracks.So yes, probes are a disposable.But that being said there are many old probes around, like Tektronix,LeCroy, that are serviceable over many years.Regards, Dana.

author: Russ
author_rank: Regular Contributor
timestamp: December 24, 2017, 06:10:45 am
content: Thank you for the responses. I apologize for being a newbie. The spare probes that arrived, are exactly the same that were supplied with Dave’s Eevblog/Brymen 235 Meter. High quality. No complaints from me.Thank You. You guys rock! 👍Russ

author: james_s
author_rank: Super Contributor
timestamp: December 24, 2017, 07:27:56 am
content: Good probes should last a long time. The only time I've had to replace my Fluke probes are a couple of bone headed mistakes years ago where I tried to measure 120V without realizing I was still set to measure current, and another case where I had them poked into something and caught it with my leg and bent the tip over.

author: Raj
author_rank: Frequent Contributor
timestamp: December 26, 2017, 12:33:26 pm
content: depends...I killed my mastech probe (and a floor tile) by drpooing 2 kg hammer onto itand my meco probes got tarnished...but eevblog proobes are gold plated (maybe jewellor to plate them if they aren't) so they don't tarnishjust don't streach them....They are simply long wires.

author: Russ
author_rank: Regular Contributor
timestamp: December 26, 2017, 01:31:55 pm
content: Quote from: Raj on December 26, 2017, 12:33:26 pmThanks. Yes, they are gold plated.Thank you.
Spark Gap across CMC - Page 1
Forum section: electronics / beginners

author: sfoipgjp
author_rank: Newbie
timestamp: March 15, 2023, 01:44:16 am
content: What's the purpose of the spark-gap in this picture? I've also seen this from DERs from Power Integrations.https://imgur.com/a/ZZdqbRQHijacked a question from another website. I didn't feel like the answers were enough. I'm hoping someone will tell me more.Thanks!

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 15, 2023, 02:08:03 am
content: Presumably, to avoid breakdown of the windings during ESD or EFT.I've seen it often enough myself, but I'm not aware of any recommendations or standards that suggest it.Tim

author: sfoipgjp
author_rank: Newbie
timestamp: March 15, 2023, 02:20:45 am
content: Thanks!Is it safe to say to always do this? There appears to be no harm in doing it consistently. I believe it does not increase PCB expenses.Please correct when I'm wrong.When's the best time to do it? Complying IEC 61000-4-2 above Level 4?
Spark gap or what? - Page 1
Forum section: electronics / beginners

author: Radu
author_rank: Newbie
timestamp: March 21, 2019, 11:32:34 am
content: Hi guys,I have a question.In the attached image,that footprint is a spark gap?In the schematic,that footprint is marked with "SB".The schematic can be found in the attached pdf.
Sparkfun Pro Micro internal pullup question - Page 1
Forum section: electronics / beginners

author: Youkai
author_rank: Regular Contributor
timestamp: March 20, 2023, 02:05:46 am
content: I have a couple questions about the Sparkfun Pro Micro and it's internal pullup resistors.1) Which of the pins have this functionality? I looked at the data sheet and can't figure it out. If anyone could point me to the location of the reference for this so I know how to find it in the future I'd appreciate it.2) If I have a pin set to pullup then I should be able to connect that pin directly to ground through a normally open switch and detect a button press by looking for a read of "0". Is that correct?3) I saw something while I was trying to figure this out that said that pullup's are better than pulldown's though I didn't understand the guy's explanation as to why. Could someone elaborate please?4) If I use internal pullups do I need to actually model it in the schematic or could I put a text node that says something like "all buttons use internal pullup"? I get that it's my schematic and I can do what I want but what's the norm?

author: pcprogrammer
author_rank: Super Contributor
timestamp: March 20, 2023, 07:21:03 am
content: 1) I looked up the Sparkfun Pro Micro and it states to use the ATmega32U4 MCU. The datasheet foundherecan tell you all about which pin has the pull up feature you need.2) When a pin is setup as input with a pull up, then yes a switch connected to ground will make it read zero when closed and one when opened, but with the internal pull up being between 20K and 50K ohm you can have more problems with bouncing of the keys. This can be handled in software or by using additional capacitors and resistors to filter it externally.3) Point to the explanation given and I might be able to elaborate on it. In principle there is no difference between them.4) There is no need to express this in your schematic. The schematic just shows the circuit as it is made. If the schematic is also used for the software development without further documentation, then it would be beneficial to place some text stating the need for using the internal pull ups of the MCU.

author: bidrohini1
author_rank: Contributor
timestamp: March 21, 2023, 06:31:50 am
content: I think you'd better post this to sparkfun forum. They can give more authentic info regarding their own product.
Sparks from 18650 battery pack while dissembling - Page 1
Forum section: electronics / beginners

author: 108CAM
author_rank: Contributor
timestamp: October 12, 2021, 12:19:05 am
content: I was taking apart a battery pack from a cordless vacuum so I could salvage the 18650 cells.I had some sparking occur and now I'm scared that the battery will explode because one of the sparks happened on the bus bar that joins the chain of batteries to the circuit board. I need to know if the battery is in danger of exploding without warning and how to cut the bus bars without using a soldering iron or creating more sparks. I also need to know what to do to make the battery safe

author: Jwillis
author_rank: Super Contributor
timestamp: October 12, 2021, 01:58:04 am
content: Sparks are not a big deal as long as you don't create a prolonged short where the battery heats up to a danger point . They need to get pretty hot for that to happen . If the battery is cold or only slightly warm your OK.Removing batteries from a pack is pretty basic . You can desolder any wires connected or just cut them . There will be two main positive and negative wires , a few balance wires and possibly a temperature sensor wire . In most packs , the batteries have been spot welded together with nickel plates . Depending on the voltage and amperage of the pack , the batteries will be in series and possibly parallel . Just cut separating each series then cut the parallel batteries into individual pieces . Then if you like just peel the remaining nickel from the battery poles with pliers. There will be jagged spurs so just clip those away. Don't grind them or you may damage the battery .

author: amyk
author_rank: Super Contributor
timestamp: October 12, 2021, 02:36:17 am
content: Some insulating tape is always a good idea when disasembling battery packs, to keep the connections you cut from shorting to something else.

author: digsys
author_rank: Unknown
timestamp: October 12, 2021, 05:21:42 am
content: I've recently attempted to split apart some 36V 18650 packs used in power tools. Yep, it is dangerous, no matter the precautions you take. A few sparks, however, are not a problem (as noted before) .. BUT the nickel welded plate is NOT easy to remove, and I have all the fancy tools. In the end I gave up, as I could see the attempt doing physical damage to the cells. They did a damn good assembly of the 20x cells. Note: using a fine blade dremel to cut up the plates didn't look safe. Good luck.I've had better luck with Tesla packs

author: james_s
author_rank: Super Contributor
timestamp: October 12, 2021, 07:35:26 am
content: It's pretty hard to make a 18650 cell explode, they typically have some sort of internal fuse that will fail and open the circuit if they get severely enough overloaded. You want to avoid sparks but it certainly won't explode. Most incidents with lithium ion cells occur while charging.
sparks & little noises - Page 1
Forum section: electronics / beginners

author: rizoma
author_rank: Newbie
timestamp: December 03, 2017, 04:48:49 pm
content: I'm using two bench single rail power supplies connected as bipolar and if I plug the power connector one pin at a time to my circuit I ear a little noise when I connect the positive and ground and a little spark while connecting the negative pin. Other than that the circuit works fine, this is just a one shot thing.Should I worry about that?

author: alsetalokin4017
author_rank: Super Contributor
timestamp: December 03, 2017, 05:01:46 pm
content: Are we allowed to know the make/model of the power supplies, and any details (like for instance a schematic) of the circuit you are powering with them?

author: rizoma
author_rank: Newbie
timestamp: December 04, 2017, 03:04:33 pm
content: Hi! I'm attaching the board, sorry got no schematics, and about the psusss:I'm using two really old italian bench power supplies so I don't think that can help much since there's no documentation about them anyway they are:- alpha elettronica al-266s- g.b.c. nt0410-00"Other than that they seems to work fine, never had any problem with these...thanks!
Sparks when connecting multimeter lead (not in amps mode)??? - Page 1
Forum section: electronics / beginners

author: JayMan07
author_rank: Regular Contributor
timestamp: April 11, 2018, 03:06:17 am
content: Several times I have seen sparks when connecting my picoscope lead to 12VDC automotive circuits.Then today I had the com lead of my fluke 87 not touching anything and when I touched a battery terminal with the positive lead I saw a spark at the tip of the lead (my buddy saw it as well). No it wasn't in amps or anything like that. Anyone else ever see this? Is it static electricityI have seen large static sparks and I have also seen sparks from direct shorts and these sparks look and behave more like static. For example, they don't leave any marks on the lead tips like a high current short would. I'm using fluke silicone leads, the super flexible kind. Maybe they can pick up static???Thank goodness it didn't damage my fluke but it was unnerving none the less.

author: Distelzombie
author_rank: Frequent Contributor
timestamp: April 11, 2018, 02:32:48 pm
content: I would say the car is the part that picks up static. Maybe ground it?
SPD3303X-E Ripple Voltage - Page 1
Forum section: electronics / beginners

author: sy
author_rank: Regular Contributor
timestamp: January 02, 2025, 09:51:41 am
content: Hi, I've just been playing around with building some circuits when I noticed the ripple voltage of my power supply seemed to be quite high.I've tried testing it with a 18Ohm 10W resistor (that's the largest power resistor I have), and with no decoupling capacitors, the maximum ripple voltage at 9V 0.5A is about 220mVpk-pk.I've looked online and they've said around 1% tolerance is generally acceptable, however, the ripple is around 2.4%.I'm not sure how concerned I should be, however, when I add a 10uF capacitor it drops to around 50mVpk-pk which gives 0.5% ripple.I guess my question is what is an acceptable variation in the regulated voltage from a switching power supply and should I be concerned?

author: sy
author_rank: Regular Contributor
timestamp: January 02, 2025, 11:19:11 am
content: Just adding on to this, the datasheet specifies the accuracy to be "Voltage: ± (0.5% of reading + 2 digits)".If I've set it at 9V, then I should be seeing: Vpk-pk = (9*0.005 + 2 digits) * 2 = 0.130Vpk-pk ripple -- however, I am seeing almost twice this value?

author: PGPG
author_rank: Frequent Contributor
timestamp: January 02, 2025, 12:27:01 pm
content: Try to be more precise in what you are writing.Quote from: sy on January 02, 2025, 09:51:41 amI understand you sow ripple at oscilloscope.Quote from: sy on January 02, 2025, 09:51:41 amWhat tolerance?Supply average output voltage tolerance? It has nothing to ripple.Supplied by you device tolerance to supply voltage change? Ripple is peak to peak so it is +1.2% and -1.2%.Quote from: sy on January 02, 2025, 09:51:41 amYou said absolutely nothing about device you are supplying.If that device is just blinking LED generator than even 1V ripple at 9V supply will be OK.Quote from: sy on January 02, 2025, 11:19:11 amAt that place I don't know how you measure your ripple. Do you use some digital multimeter?Edit later:After posting I noticed that there is SPD3303X-E in title. May be searching a net for it will give me some guess what your posts are about.