Multimeter dilemmas... - Page 1
Forum section: electronics / testgear

author: stev.dk
author_rank: Regular Contributor
timestamp: June 04, 2013, 10:07:46 pm
content: I got myself a newbecause... well the old one was crap. With no continuity and capacitance tester and no auto scaling, a precision of 90% +/- 1.000.000 counts, it was mostly good for throwing at burglars, or suicide by probing mains.I decided i wanted a good quality meter, so i can defend spending the money (and thats $100+shipping in denmark) to get it calibrated. I went for a Fluke 87 III with the nice green backlight, which i like better than the newer white/blueish. This one also came with a version V rubber holster.Here im testing it on a cheap chinese LM7805The thing is, i have a few options, that i would like some opinions on, cause summer time and holidays comming up, so i can't have all nowIf i choose to have it calibrated now, i cant afford any of these below, which i will be needing eventually... Im not sure about the which order i should go, so share your thoughts :-)-- The leads that came with the Fluke are genuine, but they have been worn really badly. The connectors and insulation is fine, but the tips aren't razor sharp anymore. I dont think sharpening them is an option, so im thinking of getting some new Fluke probes. Any idea's on what to get?-- If i buy new probes i'll have cash to get a DMMPlus from voltagestandard.comI think most of me, wants to go for the probes, and the refference... But i have no record of this multimeter beeing calibrated, so even though it's a fluke and im pretty sure its not completely out of wack, it is an older one, and i really would like to have some papers on it.Not sure if you can follow my confusen, but please comment anyway.

author: Lightages
author_rank: Unknown
timestamp: June 04, 2013, 10:17:09 pm
content: Well getting new probes is never a bad idea if the tips are a bit worn although it might not really affect anything you are doing. The voltage not reading 5v exactly on a voltage regulator is not surprising. I would trust the meter before the regulator.So get the probes and the DMMPlus and then you will know better what your meter is doing. Of course don't expect to be able to calibrate your meter yourself just with a DMMPus. At least with the reference you will have an idea what corrections to make to your meter readings should it prove to be off.

author: stev.dk
author_rank: Regular Contributor
timestamp: June 04, 2013, 10:24:48 pm
content: Quote from: Lightages on June 04, 2013, 10:17:09 pmThanks for your replyI know that the reading would not be 5V, because its a lousy regulator, so i am trusting the meter here. It was just to take a pictureIm thinking of getting probes with attaching alligator clips, so i cant have hands free, when im doing some measurements. Im thinking of using the DMMPlus to check if the meter is within spec, and to check if it's drifting, and if so, how much. I know i cant calibrate using it

author: skipjackrc4
author_rank: Regular Contributor
timestamp: June 05, 2013, 12:53:39 am
content: Quote from: stev.dk on June 04, 2013, 10:24:48 pmInstead of alligators, you might prefer minigrabbers. I know I do for most things.

author: Unknown
author_rank: Unknown
timestamp: June 05, 2013, 01:06:43 am
content: It's quite rare for these meters to drift out of spec unless damaged/abused, so I would not bother with calibration if you're a hobbyist, unless you have evidence indicating it may be out of spec. If you want you can check it with the DMMCheck, but I don't think there's much harm in just assuming the meter is correct. How often do you really need absolute accuracy beyond 1% or so anyhow? Relative accuracy (linearity) is what's usually important.For the leads, you might also consider Pomona, who are the OEM for most of the leads sold under the Fluke brand. Pick whichever is cheaper.Quote from: skipjackrc4 on June 05, 2013, 12:53:39 amAgreed. Aligator clips are not very well suited for electronics, apart from grabbing wires. Even grabbing a 1/4 W resistor is tricky, and these are huge by today's standards. I prefer the grabber hooks (the flat Fluke/Pomona ones are nicer than the round ones in my opinion) for wires and through hole stuff (more secure attachment), and the smaller pincer style (like the EZ-Hook XKM) for DIP and large-pitch SMT like SOIC and SOT23.

author: Lightages
author_rank: Unknown
timestamp: June 05, 2013, 02:57:03 am
content: I have not done my test lead shootout yet, but I can say with confidence that you would be happy with these:http://www.tme.eu/en/details/flk-tl71/test-leads-sets-with-accessories/fluke/fluke-tl71/#although the price is rather higher than in North America.

author: ve7xen
author_rank: Super Contributor
timestamp: June 05, 2013, 03:42:49 am
content: Quote from: Lightages on June 05, 2013, 02:57:03 amPomona 5519A seems to me to be completely identical aside from the branding (and Pomona is owned by Fluke) for about 50% less here.

author: bingo600
author_rank: Super Contributor
timestamp: June 05, 2013, 07:44:48 am
content: Where in DK are you located ?I have 2 x Geller 10v refs (one just a month old)I might be able to "verify" your meter with one of the meters i have.1: Keithley 2015-THD (Cal'ed May-2011) and shows 10.00000v @23c2: Agilent 3457A - Cal date ? , "6ppm" from keithley.3: Agilent 34401A - Cal date (factory 2003) , but "only 8ppm" fra keithley.I just got some resistors for cal usage also. :1x 1K00000 Vishay S102C Series Metal Foil Resistors 0.005%1x 3K0000 AE Alpha Electronic Ultra Precision Resistor 0.005%1x 12K0000 Vishay S102C Series Metal Foil Resistors 0.005%1x 10K000 Vishay VSRJ Series Bulk Metal Foil Precision Resistors 0.01%This might verify your meter , and tell if you need a cal./Bingo

author: stev.dk
author_rank: Regular Contributor
timestamp: June 05, 2013, 11:41:40 am
content: Quote from: bingo600 on June 05, 2013, 07:44:48 amI live in Herning, but i get around frequently due to friends and family living from Aalborg to Lolland-Falster, so unless your from Bornholm, it's easy for me to bring my meter along on one of my many trips. After all, playing with multimeters is just another good reason to go road tripping!I'll send a PM