I got my new fluke 289... but need some advice.. - Page 1
Forum section: electronics / general

author: Aido4ever
author_rank: Contributor
timestamp: April 18, 2011, 08:48:48 pm
content: Hi everyone.Yesterday i got my new fluke 289 . at the end i bought it from mouser and the service was good and the item arrived in two days - very fast!The thing is i got a pre-opened box... i left them an email about it. but the most importent thing which i wanted to ask you about is that the Capacitor mode is not accurate. i have about 100pf inacurecy!!! it's very hard to measure a PF capacitor using the fluke probes but using a cheap chinese capacitor probes iw working for me with "only" ~86pf inacurecy!! at-least with the Chinese probes it's stable.I found out that when it's in 1n mode and with open probes (not connected to anything) the digits are running like crazy. and when reaching to touch a button it interfering the messurment!!! i mean that when i reach my hend to the fluke the numbers are changing.... is it NORMAL?

author: Russel
author_rank: Regular Contributor
timestamp: April 18, 2011, 10:22:58 pm
content: Quote from: Aido4ever on April 18, 2011, 08:48:48 pmYou measure 100pF error while measuring capacitance with a Fluke 289, compared to what?What percentage error is 100pF?

author: Aido4ever
author_rank: Contributor
timestamp: April 18, 2011, 10:31:05 pm
content: There is allway 100pf error no matter what capacitor you test. even if you test 15 pf!!!

author: Unknown
author_rank: Unknown
timestamp: April 18, 2011, 11:39:30 pm
content: You're seeing the capacitance between the test leads, which is in parallel to the DUT (capacitor). As the distance between the leads changes, the capacitance will change. You should zero the meter with the leads not touching each other or the DUT, and then without moving the leads measure the capacitor. For better results, use shorter leads, or even better build some sort of test jig like the imageshere.This error clearly is an issue with the user not having any idea what capacitance means, not with the meter. Question: how much length of test leads needs to be close together to generate 1pF of capacitance? Answer: much less than the ~1m leads!Just as with resistance, the meter is calibrated at the jacks, so you may have to zero lead resistance/capacitance. It may even state so in the detailed performance specs that the specs for the lowest ranges are with zeroing before the measurement. Just checked, it does, so not only do you blame the meter without knowing what it's expected to measure, you even call it inaccurate without bothering to read the accuracy specs!How do you propose to measure a capacitor with some unknown variable capacitor in parallel?

author: Aido4ever
author_rank: Contributor
timestamp: April 19, 2011, 12:40:17 am
content: alm, can i ask you something? why the hell did you reply? to prove how "smart" you are or just to prove how "stupid" i am?If you don't wanna reply please don't!!Sorry for disturbing this forum with my stupid question...

author: nukie
author_rank: Frequent Contributor
timestamp: April 19, 2011, 03:38:42 am
content: Hey aido dont be rude. alm spent time writing to help you with your problem. I don't see any of his words causing any personal infliction.My 187 and 189 measures Silver Mica 0.5% capacitors with 0 pF error.It really depends on what capacitors you are measuring some capacitors have aweful tolerance, ie ceramic. Also, different meters has different measuring frequency therefore results may vary.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: April 19, 2011, 11:50:22 am
content: Quote from: Aido4ever on April 19, 2011, 12:40:17 amYes the question was stupid , but your apology is not accepted, at list by me.In this forum we have more skeptical technicians , than dudes who believe that their anonymous personality gets violated,from any simple reply to their messages.By the way @alm is an excellent member of this forum, and you are the nobody, who has lots of temper too.And so read the damn manual , and if you have issues after doing what it is printed on it ,then we will talk ( write ) about it .

author: am2pgs
author_rank: Contributor
timestamp: April 19, 2011, 12:21:17 pm
content: Aido don't ever be sorry for asking questions. I don't see anything stupid in your questions, just inexperience. We have all been there, even those who wouldn't like to acknowledge.You were rude to Alm. Alm's post although helpful, could have been less patronising.Come on guys, be courteous to each other.

author: EEVblog
author_rank: Unknown
timestamp: April 19, 2011, 12:30:37 pm
content: That is a classic beginners trap.As alm said, the test leads have capacitance that varies with how you move the leads, that will upset and affect the reading on the lowest range like you are trying to use.Same with the resistance range when you are measuring ohms, if you short the probes you will see that it does not read zero, you have to "zero out" the test leads. Capacitance is the same, except that the open probes have capacitance you need to "zero out".Dave.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: April 19, 2011, 12:50:31 pm
content: I bet that the book of the model 289 , it does write something like that.And also its an responsibility to any one who gets an complex expensive meter,to actually study the users manual.

author: Aido4ever
author_rank: Contributor
timestamp: April 19, 2011, 07:22:05 pm
content: Where do i begin?I took a look at the responses above and tell you the trough, most of them are pathetic!!!To say that I was RUDE to alm while ignoring the way he reply to my message it's pure bias.No body pointed gun to hes head and told hem to reply. If he choose to do so, then do it with some respect and without insulting.Some people in here think they so god damb smart... if alm was reading my post then he should have know that i replaced the probes to one which is for capacitance testing and that it's working quite good for me. and guess what? i actually "managed" to use the REL without the forum "help" (what a smart guy i am).This forum is for helping people and i belive even for helping people without much experience in electronics, this is all what's forum is about. So, whats the logic behind going down on a person with a question looks "stupid" in your eyes? don't you suppose to help hem and aducate hem? This way, people who are really "stupid" with electronics will be afraid to ask questions for not taking the fire.All i wanted to know if a 600$ multimeter should have so much in-accuracy in pf scale, that's it.But please don't wanna anyone responding my question. I got enough from this kind of "help" thanks.

author: Unknown
author_rank: Unknown
timestamp: April 19, 2011, 09:40:56 pm
content: Quote from: Aido4ever on April 19, 2011, 12:40:17 amI didn't call you stupid, I claimed that you apparently didn't know what capacitance was, even though you complain about the meter unable to properly measure capacitance. Ignorance != stupidity. Note that I explained both the cause and various solutions to your problem, and why a $600 meter still has this issue (you cannot change the laws of physics, even for $600), but apparently you're not educated or helped.You talk about inaccuracy. You figured out how to use the REL mode to mitigate the lead capacitance. The accuracy specs state that REL should be used for capacitance ranges below 1uF or so. Problem solved? As I said, you need some way to keep the lead capacitance stable to make the use of REL mode effective. Taping down wires is another way to do this.

author: Unknown
author_rank: Unknown
timestamp: April 19, 2011, 11:28:05 pm
content: Quote from: Aido4ever on April 19, 2011, 07:22:05 pmListening to the help offered would be a good start!QuotePathetic? If you are so sure of the answer why bother asking a question? The replies offered were of a helpful and instructional nature. I'm sorry but I take offense when young guns are rude to someone who has bothered to offer them a reply. It means those respondents are that much less likely to reply again when similar questions are being asked by someone who would actually bother to listen to their reply.QuoteNo ALM responded to an obvious newbie question in beginner terms. Had you bothered to absorb his replies along with the all the others you'd have realised by now those replies are following a similar theme. No bias about it! ALM's reply was correct, if that causes you to bounce of walls in self defence then that is your issue and no cause for any of the retaliatory accusations.QuoteNo body demanded you over-react to a clear well presented answer to your newbie question!QuoteHarden up Princess!! If you see ALM's reply as an insult you wont last long in any workplace, forum, or chat room. Heaven forbid one of the planets more condescending bastards didn't offer you the initial reply.QuoteHell yeah there are even those who ask newbie questions then carry on like a stalk when they cannot accept the bleeding obvious being included in the replies.QuoteYour confusing this with a forum for psychics! If you had all the answers why the hell did you ask the question? If your so sure your on the money Pen a letter to Fluke or head to your nearest consumer affairs dept and see how you get on.Quoteyes your quite the smartsomething. aren't you!QuoteThis is David L Jones forum and he'll use it as he damn well likes, its not not somewhere for you to make demands!!! That said, people have gone to quite a bit of effort to answer your newbie question, IE: offered help to the inexperienced. I cannot speak on behalf of the forums owner or other respondents but I can assure you an attitude check is necessary on your behalf if you want to gain benefit from any technical or engineering forum.QuoteIf your question was assumed stupid you'd have been lucky to get a reply. You got several useful replies and you thank those respondents by carrying on like a spoilt child and attacking those who'd made the effort to help. What do you consider your chances gaining further assistance if you gain a reputation as a rude prat who cannot bother to listen?QuoteThis forum has a healthy and ever growing membership of newbies who are more than grateful of the assistance offered here. Can you guess who is out of step with the rest of the forum yet?QuoteThen why didn't you ask that? Regardless of your omission this question has been clearly answered in replies above at no cost to your self. Did I hear a thank you from you?QuoteIf you do not want replies to questions then it's kind of a dumb thing to be doing, "asking them in forums", don't you think?Oh and if your over sensitive use a spell check, if there were people wanting to have a go at a newbie then you would be leaving them plenty of openings.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: April 26, 2011, 09:04:56 pm
content: Well pal , and you just get another forum to kill your time ..By the way your account here is not needed, and so it will be deleted.I have start all ready to pray for that, so to happen.