Banggood resistors - Page 1
Forum section: electronics / beginners

author: Stuartambient
author_rank: Regular Contributor
timestamp: June 16, 2016, 03:12:59 pm
content: I'm just starting out with electronics (mostly) and was looking at resistor kits. While I'd like to order from Digikey and get a good brand I'm wondering if anyone has experience with these from Banggoodhttp://www.banggood.com/Wholesale-400pcs-Metal-Film-Resistor-Assortment-Kit-Set-20-Kinds-Value-Total-p-53233.htmlI know they say metal film and am aware of the "fake" Chinese resistors that are actually carbon but for a beginner experimenting some small circuits maybe they are ok? I guess my concern is that they die during a test and the rest of the components burn.Thanks for any feedback!

author: nanofrog
author_rank: Super Contributor
timestamp: June 16, 2016, 03:24:09 pm
content: They'll be fine.

author: Stuartambient
author_rank: Regular Contributor
timestamp: June 16, 2016, 03:50:31 pm
content: Quote from: nanofrog on June 16, 2016, 03:24:09 pmOrdered! Thank you.

author: linux-works
author_rank: Super Contributor
timestamp: June 16, 2016, 04:11:21 pm
content: be aware of how things fail.carbon fails as an open, usually. is a failure of a part where an open-circuit would happen ok?metal film fails as a short, usually. same kind of question.people often don't think about this or don't care, but since you are starting out, might as well inform you so that you'll know.I have mixed feelings about 'cheap parts'. in a way, its a good start and does not cost a lot, but there can be so much doubt in bad parts, even simple switches or resistors - and if your circuit does not work, is it because of YOU or THEM?I hate having doubts like that. with test gear, I need to know that I can trust it. pretty much same with parts.how bad can this or that cheap part be? you'd be surprised.just be careful. so much can be gotton wrong in a fake or intentionally cheaply made part. the 'savings' is not at all obvious if your circuit works only sometimes or shows some strange behavior.

author: Stuartambient
author_rank: Regular Contributor
timestamp: June 16, 2016, 04:46:36 pm
content: Wouldn't it be better with an open circuit failure, with no current going forward?I'll test out the variety by a few of each kind and see how they do. Anyway, yes these were cheap but the ones down the road were 2x the price and the reviews weren't that favorable. They'll come from CA otherwise it was $2.70 from ChinaI just had a pack of 500 in my hand and now it seems to have disappeared. They seemed okay and were from American Scientific Surplus...something. The first pack I had were from Make and didn't seem all that reliable. BG has been alright with me and usually their parts have been acceptable.Guess I will find out soon enough whether I got a 'deal' or not and go from there.

author: wraper
author_rank: Unknown
timestamp: June 16, 2016, 04:57:40 pm
content: Quote from: linux-works on June 16, 2016, 04:11:21 pmHave you ever in your life seen metal film resistor failing short? Sometimes they can reduce resistance if transients are applied to them. But that is few tens of percent maximum and very rare. On significant overload they just fail open.

author: linux-works
author_rank: Super Contributor
timestamp: June 16, 2016, 05:33:32 pm
content: Quote from: Stuartambient on June 16, 2016, 04:46:36 pmthink of this case: a feedback resistor on an op-amp. when R goes higher, gain goes higher, all else kept the same.all I'm saying is to think about more than just temp-co, value, power handlilng and tolerance. how a part fails is also part of the decision process, even though - like I said - most people ignore it or have long forgotton this idea.the reality of getting fake parts into production is not zero and so I do think its part of the design process to at least think about what can happen if this type or that type of part is used and if its fake or just made cheaply. can you do something in your topology to try to fight this? that sort of thinking is useful in making 'defensive designs' - ones that can withstand abuse in many angles, so to speak

author: ovnr
author_rank: Frequent Contributor
timestamp: June 16, 2016, 05:59:04 pm
content: On open circuit failure: Say you have a voltage divider going into a sensitive opamp frontend, and the lower (signal to ground) resistor fails. Suddenly you have a hundred volts going into your opamp. Will it enjoy it? Unlikely. It might survive if it has decent ESD diodes, but not everything does.It would be preferable if it failed short in this case. Of course, the flip side is true for the upper resistor in the divider; if that fails short, it will fry everything downstream.

author: Stuartambient
author_rank: Regular Contributor
timestamp: June 16, 2016, 06:12:38 pm
content: Quote from: ovnr on June 16, 2016, 05:59:04 pmSounds wonderfulSo is there something with resistors (could be other components) where if they don't fail in the first week they'll probably last forever or there is always a risk?

author: linux-works
author_rank: Super Contributor
timestamp: June 16, 2016, 06:19:46 pm
content: one of the things you get from -real- brands is that they do research, they stick with a material type and they spec it out and publish the specs (more or less, overall its far more true of branded than no-name parts).the no-name parts could vary a lot, could have impurities, could fail later on down the line for ANY reason. too much use, even too LITTLE use.you have no idea. none at all. what's inside, how it was made, was it a 'last long enough to collect customers money' kind of part and business? some parts are like time bombs; the e-lytic caps are the usual example of that.if there is a way to cheap-out, the eastern manufacturers will find a way and do it. I wont trust no-name parts in real builds and often, its a waste of time to use them in even informal builds that are just for me. again, a parts failure or some strange behavior in a complex circuit could cause me days of tshooting and sending me down some wild goose chase. I don't need to waste time like that. life is too short to chase geese when you have better things to do"I'll just buy parts that are so easy, they can't be that bad"oh yeah? time and time again, I am tempted to try some amazon special on some parts I would use a lot of. and every single time, I have been disappointed in the metal or plastic or fitment. its just not cost effective in the long run to buy shady stuff and then waste time on it. you end up buying twice, plus the time spent is never recovered.just some food for thought. lowest -purchase- price is just ONE thing to look at. its never the whole story.

author: Audioguru
author_rank: Super Contributor
timestamp: June 16, 2016, 06:24:15 pm
content: Resistors in my cheap solar garden lights are hand painted with awful colors. Red, orange and brown look the same. Blue and green look the same. The resistors have iron wires that rust away in one month when the product is outdoors.My American or European resistors are not expensive, are machine painted with good colors and do not rust.

author: Brutte
author_rank: Frequent Contributor
timestamp: June 16, 2016, 07:39:05 pm
content: Tolerance: 1%, power: 1/4W, metal film, we ship from HK, welcome you.Pick the highest and lowest value from a batch of one nominal value. If the voltage divider indicates the ratio higher than 2% then these are "chinese brown"

author: janoc
author_rank: Super Contributor
timestamp: June 16, 2016, 08:14:23 pm
content: Quote from: Stuartambient on June 16, 2016, 06:12:38 pmResistors, even Chinese cheapies, are not something that fails often, unless you abuse them with excessive current, voltage or mechanically. If the pack from Banggood is cheap, just go for it, it is probably only a few bucks that you would lose in the worst case. I wouldn't buy precision resistors from such place, but for general tinkering they are most likely more than good enough. I am often buying similar resistor/capacitor kits to stock up my component drawers and never had significant issues. You can get rusty parts even from Farnell, so ...For experimenting with some basic circuits you really don't need to care about whether the resistor is metal film or carbon, it is more important to actuallyhavethat resistor in the first place.When buying components on AliExpress/eBay/Banggood, etc. always check the reviews/feedback of the seller, ideally on the same item. If there is a problem with it, someone will have likely pointed it out already. You could always get a DOA item, though. Shit happens, but most sellers even from China will try to help you out, because they care about their ratings (bad rating = no sales, the competition is really cutthroat and margins slim there). Just be reasonable and don't demand a free replacement for a $2 item no matter what. If the seller offers that, fine, otherwise the logistics around will cost the seller more than the item. In the few cases I had to deal with this, I have got a discount on next order or the replacement has arrived with the next order. Both fine with me. Returning money is rare, because it is expensive for them and a hassle unless you have paid with something like Alipay, especially for a small order.I am also vary of items with 0 feedback - there you are on your own. Most likely the item will be OK, but it could also be a major lemon. Buy only if you will not mind throwing the item in the bin should it not be as you have imagined.Now what I am rarely buying at these places are semiconductors - the chance of getting fake parts, especially for popular and easy to fake components (= relabel similar but much cheaper part, so it sorta works ...) is fairly high. Things like power MOSFETS and ICs I will rather order from an official distributor. On the other hand, if you only need a few jellybean transistors and LEDs for breadboarding, that's mostly no problem, even if you get relabeled/fake parts. They will rarely sell you a transistor or LED that don't work at all and for a breadboard it doesn't really matter if the LED dies 50% earlier than a real KingBright or Cree one. Power LEDs can be iffy, though, often with dead chips.The other thing I don't recommend buying from China are electrolytic capacitors, especially if it is for repairing a switching power supply. You will almost universally get junk.Basically, if you are buying parts for just trying things out and learning, don't worry too much about it. If it is for something critical - like a school project, power supply that could fry something expensive if it fails, something for your job, demo for the investors of your startup - there saving a few pennies by not buying from a big name distributor could cost you a lot more if you get unlucky. As always - it is a trade-off.

author: ZeTeX
author_rank: Frequent Contributor
timestamp: June 16, 2016, 08:37:16 pm
content: Resistors most of the time you can get metal film resistor from eBay no problems, but capacitors? totally different story.Never ever build a project using one hung low capacitors, they will fail and they are not meeting their specs 50% of the time, go only from good brands - and most of the time they are not expensive at all.I never had problem with eBay resistors, they are really just a resistor and for general purpose stuff I think they are great.I know that one hung low caps have very bad reputation as they fail a lot, but what about resistors? do they also fail a lot compare to a good brand? did somebody test it?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 16, 2016, 08:49:59 pm
content: I can't even imagine why you'd shop for something like resistors at a cheap Chinese retail site like that.Digikey, of all places, makes a good bit of their money onproduction quantitiesof resistors and capacitors. They're competitive, and manufacturers know it.Not that their small quantity pricing is very generous, but it won't be from any place that sells parts of higher quality than floor sweepings.If you just need a random kit of values, just to get started, sure. Just don't complain if they're impossible to solder, or out of tolerance, or burn out easily, or age terribly, etc. This is the risk you are taking. Be aware of that risk, and accept it.You can replace values as you go, buying strips of a few hundred from mainstream suppliers, so that your collection improves in quality with your knowledge and experience.Tim

author: linux-works
author_rank: Super Contributor
timestamp: June 16, 2016, 10:24:04 pm
content: don't underestimate how badly things can be made.I bought some color coded vertical pin headers, usual .1 spaced stuff. "how bad can it be?" I thought. there are 2 things, the plastic and the metal pins.well, you can imagine that this was also a lesson for me. the plastic melts if you look at it the wrong day. or if you happen to be soldering on a day that ends in the letter 'y'the metal, it would not easily take solder and since I had to leave the iron on longer to get any kind of connection, the plastic melted and deformed. useless. had to throw it all away. nice bright pretty colors, though! beautiful plumage, mate! (lol)look, the race-to-the-bottom is in full swing right now. things that you think 'how bad can it be?' - are PRETTY DAMNED BAD.brittle plastic, colors that fade or wash away (color codes), wires that have unknown metals in them, unsolderable in any clean way, materials that are brittle and break with strain or temp changes. the list goes on and on.the depths of 'cost savings' that vendors will go to has no limits. no limits at all. they'll happily make things they KNOW will blow up in your face. they simply don't care. this is the world we live in and its useful to know this rather than find it out the hard way.

author: Stuartambient
author_rank: Regular Contributor
timestamp: June 16, 2016, 10:38:59 pm
content: Thanks guys! At this point I'm still struggling with bending the leads and getting them to go into the breadboard straightIf I blow half the pack just practicing that part, it was money well spent. Banggood is alright but I know they are cheap no name possibly unreliable components. It'd be nice to have a place to shop close by if I am going to need things in small quantities. But with digikey they ship usps and for under a pound it was a few dollars. A pound of parts is quite a lot I imagine.Good to hear about other components like caps, semiconductors, etc. BG has bags of those as well but I'll avoid. Once I refine my list of needed parts I can try Digi-key or Mouser, or anyone that sells known stuff. I was looking at Sparkfun which is about 15 minutes or so away. From comments on their site products vary in quality but also noticed that while they have most common components, value ranges have some gaps.

author: nanofrog
author_rank: Super Contributor
timestamp: June 16, 2016, 11:07:56 pm
content: Quote from: Stuartambient on June 16, 2016, 10:38:59 pmIf you can wait a bit on delivery,Tayda Electronicsmight be of interest, as the parts are inexpensive (located in Thailand). Definitely suitable for bread boarding (jellybean parts).Regarding electrolytic capacitors, stick to name brands.

author: Stuartambient
author_rank: Regular Contributor
timestamp: June 16, 2016, 11:21:29 pm
content: Quote from: nanofrog on June 16, 2016, 11:07:56 pmI was thinking about them actually. Seen them mentioned in some other threads. I'm not sure if I read much on the quality though. One thing that interested me about them is they have a warehouse in Durango, which is within my state. Nothing on their site though indicates where parts are located or a way choose.I can't tell who makes their resistors. I saw some elytic caps with Vishay on them, so I gather they are for real.

author: nanofrog
author_rank: Super Contributor
timestamp: June 16, 2016, 11:31:12 pm
content: Quote from: Stuartambient on June 16, 2016, 11:21:29 pmThe resistors are usually fromRoyal Ohm.For example, go toCoated, thenMetal Oxidefrom the drop-down list, and you'll get the relevant data sheet.

author: System Error Message
author_rank: Frequent Contributor
timestamp: June 16, 2016, 11:40:26 pm
content: Just thought i would offer some advice here about testing. Components perform differently under different conditions such as when under load or even under temperature.If measuring the resistance can be done in parallel, measure it while it is active with load. Does the component get hot during testing? Does the resistance change? For learning i think cheap components are the way to go as you probably wont be using them in anything critical. If you plan on using them to repair stuff or as a business you should test the component to see how it performs normally and when at worst for it's purpose. Dont forget a voltage test to see if something like resistance would still be the same under different or even very high volts if the component will be used with lots of volts.Also component lifespans can vary as well. Some things can be cheap because they are simple and will last long. Resistors are just a long piece of cable so theres nothing to them other than the material used to make them. Cheap resistors do fine as long as you dont pass too much energy through them.

author: FlyingHacker
author_rank: Frequent Contributor
timestamp: June 17, 2016, 01:03:49 am
content: I know there is always a lot of talk about failure modes, but most of these are purely anecdotal as far as I can tell when looking for actual data, rather than grey beard stories.We need real hard data. Here is some, but even this does not go into detail about the sample sizes, etc.http://www.electronicsbus.com/resistor-failure-modes-resistor-reliability-design-guide/I think you should assume any resistor can fail open or it can fail short. It can also shift in value. There is not much of a hard and fast rule. Film resistors are not much more likely to fail short than carbon comp (just slightly, see the link).Would love to see more in depth studies.

author: macboy
author_rank: Super Contributor
timestamp: June 17, 2016, 03:26:22 pm
content: When you get them, check the temperature coefficient. This is a quick and easy test to see if they are in fact metal film or just cheap carbon ones painted blue. To do this, measure the resistance then (while still measuring) touch it with your hot soldering iron. They value should change very little if metal film; max 1 or 2 percent for a couple hundred degree C change. A carbon will change more.

author: Stuartambient
author_rank: Regular Contributor
timestamp: June 17, 2016, 04:55:43 pm
content: Quote from: macboy on June 17, 2016, 03:26:22 pmTouch the resistor itself or leads?

author: nanofrog
author_rank: Super Contributor
timestamp: June 17, 2016, 05:21:48 pm
content: Quote from: Stuartambient on June 17, 2016, 04:55:43 pmThe body of the resistor, not the leads.

author: Stuartambient
author_rank: Regular Contributor
timestamp: June 17, 2016, 05:34:26 pm
content: Quote from: nanofrog on June 17, 2016, 05:21:48 pmOk thanks. I know there were some posts around that might have mentioned scraping material away to see if carbon or metal. Sounds like this might be a less destructive method.I'll also update the thread in case anyone is interested in results.

author: rstofer
author_rank: Super Contributor
timestamp: June 17, 2016, 05:37:04 pm
content: I bought a resistor and capacitor kit from Jameco Electronics a long time ago.What I have discovered is that I only need about 8 values of resistors - 220, 330, 470, 1k, 2.2k, 4.7k, 10k, 100k. I could get buy without the 100k. The point is, why not just buy a hundred or so of the most commonly used values and then, when you build a special project and plan to order parts, throw in a hundred or so of a couple more values.There are drawers in the resistor box that I have never opened. What in the world would I do with megohm valued resistors?In the ceramic capacitor kit, I use two values: 0.1 uF and 0.01 uF. Every once in a while I need something in the 22 pF range for an oscillator. I am more likely to need 10 uF or 100 uF electrolytics or tantalums.Most of my projects are related to uCs or FPGAs. But even with op amp circuits, I could get by with my limited selection. Now, I did use some 1 megohm resistors and 1 uF capacitors for my analog computer but I bought them when I ordered the op amps. SMD and precision for the resistors and polystyrene for the capacitors. Nothing I would care to stock.

author: linux-works
author_rank: Super Contributor
timestamp: June 17, 2016, 05:40:27 pm
content: lol.1uf and 1k can get you by for so many things.there is a special name for them; the 1k is a 'floor resistor' and the .1uF is a 'floor capacitor'.you know, you need a decoupling cap, its late, you need to finish a project and so you look on the floor for something close. you end up using a 'floor capacitor'(grin)

author: Stuartambient
author_rank: Regular Contributor
timestamp: June 17, 2016, 06:33:29 pm
content: It would be good if I could define which values would be needed and which ones not. I've been spending more time reading the basic stuff and haven't really had a chance to pick some circuits to try. However I helped my son get started with soldering, one of the European siren kits. A great value kit btw for learning soldering and electronics as well. Anyway, it included a 68, 2-470's, 1k, 2-10k's, 2-22k's, 47k, and finally 2-56k. Seven values and the circuit is somewhere between simple and more complex. To me, it seems like a big variety of values. Definitely makes sense though if I have repeating values to stock up on those in particular.

author: janoc
author_rank: Super Contributor
timestamp: June 17, 2016, 07:11:31 pm
content: Quote from: T3sl4co1l on June 16, 2016, 08:49:59 pmNot sure how it is in the US, but here in Europe you pay 7-20EUR shipping & handling for orders under 30-60 EUR (depends on vendor). Also a hobbyist is not going to buy full reels of 4000 resistors of a single value to qualify for the "production quantity" pricing. Here in France I have RS Components the cheapest, with about 7 EUR shipping charge. Digikey is asking for around 15EUR S&H unless I order for at least 60 EUR + customs & BS paperwork, because they ship from the USSee why I am buying my resistors from AliExpress?Most hobbyists want to actually build stuff, not wait months until they have accumulated enough projects to qualify for free shipping from Digikey or Farnell. Paying 10EUR shipping for 2EUR in resistors is nonsense, which is why people buy small quantities from eBay, AliExpress, Tayda, etc. instead. Also the prices are often (much) better. For a penny-pinching hobbyist it makes quite a bit of difference.I do miss the times when you could you walk up to the counter of your local electronics store and pick up few basic parts, solder, spool of wire and just go home and start working on a project. Having to do everything though mail order is a pain, especially for penny items like that.

author: janoc
author_rank: Super Contributor
timestamp: June 17, 2016, 07:13:49 pm
content: Quote from: Stuartambient on June 16, 2016, 11:21:29 pmTayda is quite decent, indeed. Not a large choice, but low prices and they are reliable.

author: Stuartambient
author_rank: Regular Contributor
timestamp: July 01, 2016, 10:29:33 pm
content: Quote from: macboy on June 17, 2016, 03:26:22 pmJust wanted to update on BG resistor kit. I did some random meter reading and overall the 1% tolerance seems to be right. Also tested with the iron on a 47K. Started at 46.3, once iron touched it went down to 45.5 (then back up). Iron was touching the resistor body for 1 - 2 seconds. So they appear to be metal film, at least according to this test.

author: edavid
author_rank: Super Contributor
timestamp: July 02, 2016, 12:29:57 am
content: Quote from: Stuartambient on June 16, 2016, 11:21:29 pmFor US orders, Tayda does bulk shipments from Thailand to Colorado, then ships the individual orders by USPS from there.The problem I have had with cheap China resistor kits is that the leads are thinner than normal, so they are a little tricky to use in a breadboard. They are OK for soldering though. The resistors I have bought from Tayda have normal leads.

author: edavid
author_rank: Super Contributor
timestamp: July 02, 2016, 12:34:39 am
content: Quote from: rstofer on June 17, 2016, 05:37:04 pmThat may be fine until you start doing repairs, but then it becomes convenient to have a wide range of components at hand.

author: Kirr
author_rank: Regular Contributor
timestamp: July 02, 2016, 02:03:12 am
content: It may be worth mentioning that you can often obtain a missing resistor by combining the ones you already have. For instance using network finder tool in my sig.Most of time it does not make much sense to buy a single resistor - you'd want a 100 for a price break. However it's a waste if the other 99 sit in the box forever. In such case just combine your stocked resistors to get the missing value. Especially useful if you are in a hurry and don't want to wait for delivery.

author: Watth
author_rank: Frequent Contributor
timestamp: July 02, 2016, 01:38:09 pm
content: Quote from: linux-works on June 16, 2016, 04:11:21 pmI bought jumper wires (from aliexpress). Oh how fun was it to lose hours trying to figure out why things didn't work (and why mosfets burnt), until I discovered some of the jumper wires were deffective.Now, if I ever order jumper wire from this type of sellers, I'll have to test each on of them.

author: Stuartambient
author_rank: Regular Contributor
timestamp: July 02, 2016, 02:32:55 pm
content: Quote from: Watth on July 02, 2016, 01:38:09 pmMakes you wonder how anyone can screw up jumper wires. Isn't Aliexpress and even Banggood basically multiple vendors selling under one umbrella company?

author: linux-works
author_rank: Super Contributor
timestamp: July 02, 2016, 05:48:53 pm
content: I've had jumper wires be bad right out of the bag, before.I would joke with the sellers:"look, I bought a bunch of shorts, but you seemed to have mixed in some opens along with the shorts. they all look the same and I can't tell, so maybe next time, mark the bags with the shorts and don't let the opens get mixed in by mistake"I'm not sure they ever understood my joke. and I never buy cheap jumpers anymore. time wasted makes it false econ. and I can create my own opens, for free, without any of THEIR help (harumphs!)

author: Stuartambient
author_rank: Regular Contributor
timestamp: July 02, 2016, 05:56:15 pm
content: Quote from: linux-works on July 02, 2016, 05:48:53 pmReminds me of a laundromat I once knew.

author: Kalvin
author_rank: Super Contributor
timestamp: July 02, 2016, 09:49:09 pm
content: You should make a difference between resistors and precision resistors. Typically the design requires only few precision resistors while the rest of the resistors are used for biasing, pull-up, pull-down, led biasing etc. ie. non-critical non-critical parts of the circuit. Similar situation is with the capacitors, most of the time you require bypass capacitors and less critical capacitors, and require possibly only few precision capacitors. For example, I have bought cheap resistors and capacitors from eBay (assorted kits of TH resistors and capacitors for breadboarding, assorted kits of SMT 1206/0805/0603/0402 resistors and capacitors), knowing that they may used only for the less critical parts of the system. When my design needs precision components, I will order them from a reputable distributor.

author: HwAoRrDk
author_rank: Super Contributor
timestamp: July 03, 2016, 05:31:30 pm
content: Quote from: Watth on July 02, 2016, 01:38:09 pmUgh, that happened to me a while ago. Crappy jumper leads where virtually all of them would not register any continuity on the meter. I thought I'd been ripped off and sent fakes, until I realised what the problem was.These jumpers had a plastic sheath covering the crimp on the pin (unlike most others I've seen where it is moulded rubber) that was glued on. The problem was that the glue was also all over the pin too! It was some kind of cyanoacrylate (superglue) that is virtually transparent, so I hadn't noticed it.Scraping the glue off the pins with a knife soon restored them to proper working order. But it was a tedious pain to go through all 100 in the pack.What a dumb way to assemble jumper wires - rendering them useless out of the box. I'm going to steer clear of those in future and always buy the moulded kind.