Really simple question about Identifying Caps and other. - Page 1
Forum section: electronics / beginners

author: PhynixViking
author_rank: Regular Contributor
timestamp: December 05, 2012, 09:17:19 pm
content: OK So... I hope it's simple, lolI do a LOT of scrap/salvage on old electronics. As well as always like to buy those "cheep bulk mix" deals (of new parts) that pop up here and there. I'm left with a bunch of disk shaped 2 pin guys.I know some are Disk capacitors, and some are MOV's...My question is, how can I tell them apart? And is there other things that come in that similar disk/2pin shape that they could be?NOTE: I already tried to test the capacitance on them to see which is which but MOV's end up having capacitance too!!Thanks for any advice and help I get for this. ^_^One last thing... is there a list of every Voltage/Amp Regulator out there? and/or a way to identify these heat-sinked transistors? (I have a good like 500+ of them that I don't know what they are and can't find any data sheets or info on them.)

author: T4P
author_rank: Super Contributor
timestamp: December 07, 2012, 06:12:23 pm
content: eEasy. Usually MOVs are labelled something like 10K470 and for larger ceramic round caps the size of a MOV usually will be something of 0.1uF400V or somethingVoltage regulators? Here's a few of mine that i frequently see and probably useLM317/337 - 317 = 1.5A 337 = -1.5ALM338 = 5A regulatorsLM723 = 150mA regulators, usually used with a pass transistor in cheaparse power supplies to achieve 0-15VLM78033-12 = 3.3V to 12V respectivelyLM7905-12 = -5V to 12V respectivelyAMS(chinese clones)/LD(ST)/LM(TI now or previously NatSemi)1117 TO220 versions - 15V MAX INPUT LDO 500mA-800mALM2940 = MAX 26V 1A LDO regulatorsLM2577 = Simple Boost Switching RegulatorsLM2596 = Simple Buck Switching Regulator

author: PhynixViking
author_rank: Regular Contributor
timestamp: December 09, 2012, 03:01:10 am
content: OH! Cool thanks for the reply! ^_^Ok so... for example... i have:S20 K300 - this is a mov?103K 1KV - a....cap?K15 L5R1 - ...umm... Mov?SCK 059 - no clue...6D-22 G D - also no clue.. lol(i should probably just organize them and take pics of each group to show)then i have one with a million things on it...NS Y 472 560-2 H3N LL2 565-1 Yno clue... i actually have a few like this one... with symbols on them too.AH! Yes... perfect! I have some of those! ^___^Any more to name I'd love more list. lol (I wish there was just a website that had all of them not by model but by type/category)Do you happen to know what the 640 (IRF640A) and 630 (IRF630B/IRF630) do? I've looked them up and I'm not sure if i get it... (I'm kinda still beginning or early intermediate... idk I've done repairing for years and very basic things (amps/power supplies) and not much else.)

author: T4P
author_rank: Super Contributor
timestamp: December 09, 2012, 04:26:16 am
content: QuoteUpload some photosQuoteWell yeahQuote

author: mariush
author_rank: Super Contributor
timestamp: December 09, 2012, 05:24:03 am
content: When you see a value like 103K , most often it's the standard notation for the capacity of the capacitor. The last digit is the number of zeros after the value. So 103k is 10 x 103pF or 10 nF or 0.01 uFDo you happen to know what the 640 (IRF640A) and 630 (IRF630B/IRF630) do?IRF is the name of the company ... International Rectifier. I assume you didn't even try googling for IRF640A because the first result is a datasheet. Always search for the full code, then search for everything less the last digits or characters in case there might be a similar chip (for example if you don't get results for IRF640A, search for IRF640)use Findchips.com with some product codes or partial product codes, use digikey.com and newark.com/farnell.com to search product codes on them.

author: M. András
author_rank: Super Contributor
timestamp: December 09, 2012, 05:11:55 pm
content: cap markings are one thing. but i dont get how cant you search the number written on those 3 terminal fet packages even the voltage regulators

author: SeanB
author_rank: Super Contributor
timestamp: December 09, 2012, 05:23:52 pm
content: Look at the circuit and guess what the part does, then enter the numbers and a space then the guess of the function. eg 113 regulator............ a3h transistor...........

author: PhynixViking
author_rank: Regular Contributor
timestamp: December 09, 2012, 08:11:30 pm
content: OH thanks everyone for the replies! ^__^I figured out the capacitor code, I'm use to electrolytics and they are normally just plainly marked on them.. it reminds me a bit of the resistor coding. Anyway!I've cut the pile down to a small maybe 100 more to identify (WOOT!!!!) I think the rest might be mostly Movs... I have very little experience with Mov's...I do how ever have some odd ones...mariush- I did use google but... sorry new to some things, didn't understand what it was exactly. I'll have to look into FET's... I've been learning a lot more about electronics (above and beyond just replacing caps and making simple power supplies or LED arrays etc.. lol) Now that I think of it... I might of searched for them eariler in the year and types in IRF and not just 640 LOL bla...M. András- A lot of them don't come up... and I've tried various electronic suppliers and MANY don't come up there... I think it might have to do with that a lot of my stuff is salvaged form (for example old CRTs) old electronics or broken things so a lot of it might be out-dated? Maybe other/newer models/numbers are used today... not sure... also I think a few times I put in the manufacture code WITH the model so I didn't get many or the right results... (so often i get websites that are trying to sell it but don't have what it is... idk... scam or fake websites? psh...)SeanB- Hm... I've been learning more and more recently... I've just gotten into Mov's most things I can identify right off the bat but with the old electronics I often salvage I find myself finding pieces that idk if they aren't avalible anymore or just odd-ball stuff.T4P- A fet? OH I knew that!!! I totally knew that!!!! ...ok no I didn't... *looks up what a "fet" is* LOL Pictures are here!And funny you mentioned tubs... I just remembered I have like... maybe 50 tubs laying around here some place.EVERYONE - again thanks for comments and help!!! I like it! It is appreciated! ^__^I will have to do a youtube video explaining this same problem I have, if anyone has a youtube account I'll happily mention you as a "thanks to" for the help! ^___^ (you know... explaining how to identify the odd ones Mov's from cap's and might be cool to mention this site/forum... not that I have many subscribers or people watching my videos, lol but still! anyway...)I think you'll see what I mean in picture D...I think lot A are all Mov's.... and C i thought were caps but they don't act like it... (the multimeter and the capacitance meter BOTH are showing odd results on them. They have capacitance but its unstable or changes?)And when you look at B and D... (especially D) I'm lost... LOL and some where I have one that is not marked at all... and looks like a funky battery but I KNOW its not a battery. I'll have to look around where I put it.Anyway! Again... BIG thanks!!! ^___^

author: mariush
author_rank: Super Contributor
timestamp: December 09, 2012, 08:46:14 pm
content: The ones in your last picture and possible the dark green ones in the third picture are thermistors :http://en.wikipedia.org/wiki/ThermistorThey're resistors that change in value depending on temperature, and are often used to do inrush current limiting:http://en.wikipedia.org/wiki/Inrush_current_limiterAs a very simple explanation, power supplies can have very big capacitors in them, so when they're plugged in these capacitors pull a lot of current from the wall until they charge up (a few ms) ... possibly more than 10-20A of current.With so much current, it's possible to trip the fuse in your house. Inrush current limit restricts how fast those capacitors can charge by putting one of those thermistors on the line. As the thermistor gets warm, the resistance changes to the point it's as if the thermistor is not even in the circuit.NTC written on them is a sure way to know that's a thermistor.As for notations... I see there in pictures 3R0M ... that could mean R is like a decimal point... so you have 3.0 ohm or 3.0 megaohm since you have the M there.L5R1 following the same rules may mean 5.1 ohmAnyway, put your multimeter on resistor measurement and use a lighter or something like that to warm them up and see how the resistance measured changes.Not sure what the green ones are, if they're MOVs or thermistors.The blue and yellow ones are varistors or MOVs ... see here a small explanation :http://www.vishay.com/docs/29079/varintro.pdfAs far as I know, the blue color is somewhat of a "certification" they're suitable for protection, for mains usage etc but I may be wrong.The logo that looks like an italic reversed UR is just the logo for UL (underwriter's laboratories), a sort of certification lab, won't tell you much about the parts.

author: bitwelder
author_rank: Super Contributor
timestamp: December 09, 2012, 09:27:05 pm
content: In the A-lot there are ceramic capacitors. Most of the markings and symbols are the various safety compliance markings.Check e.g. this pdf from TDK with the explanation of various markings (capacity value, rated voltage and safety marks):http://www.tdk-ninebig.com.tw/E053.PDF

author: PhynixViking
author_rank: Regular Contributor
timestamp: December 10, 2012, 01:16:45 am
content: bitwelder- Woah! I hadn't realized there were so many certification logos and.... certifications for that matter! lol Thats a cool link you sent me, I might have to print it up and hang it up some where around the office. ^_^mariush- OK! So I'm not crazy! It was changing because I was holding it, LOL (side note, my grand father which was VP of a company that made transformers and capacitors for government and power plants etc... was JUST telling me about Thermistor's and that I should look into them.)That makes perfect sense! Amp draw creates heat... heat makes thermistor add resistance.... resistance lowers the power being drawn. So result would be... instead of say 20 amps for 0.5 seconds... it might be 10 amps for 1 second or 5 amps for 2 seconds... etc? (well about that... i know its probably faster.)Then cooling a power supply too much might be hazardous?So if it said... say... 1R8K that would be 1.8 Kilo-ohms? and.... 25R0K would be 25.0 Kilo-ohm? etc...does the L in the front mean anything?I just got into mov's... they seem kick ass to me!Do MOVs blow like fuses?(like they burn out and then you have to replace them) or more like transistors that when "active" they do that but when voltage is normal again it returns to normal?Again! Thanks everyone so much for the help!!! ^__^ Very much appreciated!

author: mariush
author_rank: Super Contributor
timestamp: December 10, 2012, 01:44:06 am
content: It's the other way around...See this:http://www.princeton.edu/~cavalab/tutorials/public/Thermocouples.pdfWhen cold, the current flows slowly through the thermistor (the resistance is high). As current goes through, the insides warm up and the resistance decreases therefore more current can flow through the thermistor, IF something demands it. Gradually, thermistor warms up to the point where it becomes like a 0 ohm resistor, like a jumper, or it's in such way selected that at the regular temperature it will be at it will restrict the maximum current to a few Amps (but a value higher than what the power supply needs)very basic example... you have a 400w power supply, that means it will pull about 500w when loaded to the maximum, so that's 500w / 115v = 4.3aThe power supply will however pull about 20-30A when it's plugged. So a thermistor could be selected to limit the inrush current to 6A, then as it heats up it will allow up to 10-14A or something like that.So even if the power supply was really cooled down, or in a cold room, the thermistor would still allow more than what the power supply needs, or just about that much.See this explanation about MOVs :http://www.cliftonlaboratories.com/metal_oxide_varistor_%28mov%29.htmThink of them like fuses, but the other way around. When too much voltage goes through them, a link is formed and the current goes through the MOV instead of going further into the device.You'll see MOVs connecting the Hot and Neutral to the earthing (ground) of the power supply) - if there's voltage spikes, movs trigger and close the circuit with the earth and electricity goes through the shortest path, to ground.Naturally, when the voltage or current spike is too much, they may blow upAt least that's how I understand it, i'm not an expert on these, by far.

author: Kremmen
author_rank: Super Contributor
timestamp: December 10, 2012, 07:07:07 pm
content: Plenty of info already in the previous posts. Just let me add a couple of details:In pic ALOT you can see certain key lettercodes in the caps. Specifically, i mean the codes X, X1, X2, Y, Y1, Y2 and combinations of those. These codes indicate the component is certified to be used as part of aline filter circuit subject to full line voltage stress. Those classified X are valid for non-safety critical connections i.e. between phase and neutral wires. Those marked Y are permitted for dicruits where safety of life is at risk, i.e. connections between live wires and safety earth. This connection is regularly needed in switching power supply EMI filters. And those are real common these days.As to MOVs, the previous explanations are basically correct. A MOV will go low resistance once its threshold voltage is exceeded. It will return to high resistance once the surge has passed. While low resistance it is basically a short, so you need to pay attention to surge current limitation in order to avoid a fire hazard in the supply wiring. Basically what you need is a fuse or breaker with sufficient rating in front of the MOV to clear the circuit in case the surge persists. You must not specify a too close MOV threshold in relation to the normal circuit voltage. Where i am, the 230VAC supply usually has a 275 VAC rated MOV protection. The DC voltage ratings will be sqrt(2) higher of course.Also bear in mind that the so called clamping voltage over the MOV terminals will _not_ be zero when it is conducting. In fact it will be higher than the threshold voltage. So when we say it has low conduction resistance, it means the _dynamic_ resistance i.e. dv/di in the conducting state is low. See e.g. this paper more:http://www.cliftonlaboratories.com/metal_oxide_varistor_%28mov%29.htm

author: PhynixViking
author_rank: Regular Contributor
timestamp: December 11, 2012, 09:52:12 pm
content: mariush- AH! Ok I get it... Hmm... those are kinda neat. I already have a cool idea to use one as a shut off for a power supply if it gets too hot... like maybe one connected to a transistor or, one connected to a relay, that when heat exceeds an amount it would click off... maybe to a charged capacitor for an amount of time (psh... 20... 30 seconds?) Or... Wait... what if I had 3 LED's that when temp was at X temperatures the first LED goes on, then hotter the second, and when its "dangerous" the 3rd would go on... Hmmm Ideas!!!(...yes I know that's not necessarily the purpose for them, LOL)Kremmen- So... MOV's will slowly change or all at once? I'm wondering if I would make a MOV tester... like... a device that would send volts at low amps but also have a type of diode bridge or just a diode (have to think about it) so that you can test the resistance with a multimeter but not be effected by the voltage? Or something simpler as a LED going on or off to show if its working...UGH! This forum/website... giving me project ideas!(and learneding many things! lol)PS: Link seems neat! ^_^