Tips for multimeter use - Sporadic results - Page 1
Forum section: electronics / beginners

author: Kyburo
author_rank: Newbie
timestamp: September 16, 2014, 08:23:08 pm
content: Hi EEV Forums,This is my first post here after being pointed this way from another forum. Since then I've been watching a ton of the EEV vids and it's basically got me wanting to playI've just today received a Uni-T multimeter in the post (UT61E) after watching a bunch of video reviews and reading articles on features to look for etc. This'll most likely be an incredibly newbie question, but how tolerant should the meter and probes be out of the box?Watching another vid talking resistors and bits, trying to learn the interface of this Uni-T I wanted to check the resistance across the probes themselves so as to know what value to account for in any future readings etc. The result seems wild. As the contact between the probes is moved (even the slightest movement due to the slight vibration/motion I'm unable to prevent) the result can jump from anywhere around 0.3ohms up to thousands of millions of ohms. The same is true of using the continuity tester, the beeping is pretty wild when the probes are run along side each other.I've not as of yet used this in anger on anything, so perhaps this is due to the meter itself or the probes being dirty etc? Really just looking for some advice on what to do. Is this normal? Should I attempt to clean the probes with alcohol first? Is it worth getting more decent probes? Perhaps it's my technique and you should always use the tips or something similar?Thanks for any help you can give!Cheers

author: kingofkya
author_rank: Regular Contributor
timestamp: September 16, 2014, 08:46:13 pm
content: That is where a good probes comes in handy, needle sharp so you can cut though anything in the way, and gold plated help a lot with getting good contact. I haven't used the Uni-t probes but in general you need to apply some force to get a good connection, but there is better ones that the ones that come supplied with most cheaper multimeters.IF you want a really good pair try this brandhttp://www.probemaster.com/under "DMM Test Leads" but if your just starting out probably not worth itThere aroudn $25-30 in the usa not sure if you can get em internationally. They used to be be under $20 but daves review/mailbag ruined that

author: Kyburo
author_rank: Newbie
timestamp: September 16, 2014, 09:20:59 pm
content: I tried using greater pressure and that's sorted it! It's now fluctuating by .1ohms rather than a few tens of thousandsThanks for helping me, that was pretty stupid after all

author: Wytnucls
author_rank: Super Contributor
timestamp: September 16, 2014, 09:28:20 pm
content: It is not stupid at all. It often happens that new probes are covered with manufacturing residue and it is best to clean them with alcohol before use.

author: Kyburo
author_rank: Newbie
timestamp: September 16, 2014, 09:38:05 pm
content: Yeah they do look like they've a light coating of dark residue speckled on each, especially towards the base. I'll try to see if I can clean them up a little as well.

author: Matje
author_rank: Regular Contributor
timestamp: September 16, 2014, 10:56:01 pm
content: Quote from: Kyburo on September 16, 2014, 08:23:08 pmHmm, I had that with my UT61E probes too. See below...Quote from: Kyburo on September 16, 2014, 08:23:08 pmThat may happen legitimately with somewhat fast continuity testers as in the UT61E.Quote from: Kyburo on September 16, 2014, 08:23:08 pmYou can attempt to clean them.Ultimately you should really get better probes. Mine turned out to be defective (well, one of them).I removed the plastic from the banana plug side and the construction turned out to be just crappy, with failure not an option but a certainty (see thread "Why do DMM leads have such high impedance"). I retired them and got myself a reasonably priced (about 25 Euros I think) pair of Fluke probes.

author: Lightages
author_rank: Unknown
timestamp: September 16, 2014, 11:43:34 pm
content: Use #0000 steel wool and alcohol to clean the probes. Do not use sandpaper or abrasive pads as that will damage the plating and make them oxidize faster.

author: CrashO
author_rank: Unknown
timestamp: September 16, 2014, 11:54:38 pm
content: Quote from: kingofkya on September 16, 2014, 08:46:13 pmFranky has some nice (and fairly cheap) gold plated probes with silicone leads probes in his store for $16.99 shipped.Brymen Silicone Gold Plated Test LeadsThe probemaster ones are nice to, but last time I checked they charged a fairly steep shipping price. (And for us peepz in the EU, shipments from the US are almost always checked and charged for import taxes (VAT) (if order is over 22 euro). China stuff, not that often.