I tested a $2.31 set of multimeter probes. The results will surprise you :D - Page 1
Forum section: electronics / testgear

author: Chumanista
author_rank: Contributor
timestamp: September 01, 2016, 10:34:37 pm
content: UPDATE:Seriously though, they work much better than the stock Uni-T set, survived months of use, nothing to complain about.No, this is not a sponsored video, I just really liked the product

author: joeqsmith
author_rank: Super Contributor
timestamp: September 02, 2016, 02:13:55 am
content: Looks good. Nice job with the video too.

author: BMack
author_rank: Regular Contributor
timestamp: September 02, 2016, 05:15:59 am
content: I used to use cheap probes, they work and there wasn't a difference in resistance in the leads. The downside is that pvc isn't silicone(you can't go back to pvc) and they didn't last. I used to replace leads about once every few months, one lead would just lose connection. Sometimes the probe pin would fall out or get pushed into the probe. At a certain point I decided it wasn't worth the hassle of waiting for them to come from China so I'd order more than one set at a time. Then I'd get different types than pictured so I'd have to reorder and wait. Now I use Fluke leads, the type that is right angle banana plug to straight banana plug with slip on probes...this way if something goes bad I replace the problem piece and keep going. This also makes it easier to use different accessories. For someone that repairs electronics as a profession, this was a necessary change, it just made my life easier. For the average user, the cheap probes will probably do the task just fine.

author: redg
author_rank: Regular Contributor
timestamp: September 02, 2016, 06:24:45 am
content: The wires on my leads say what company made the wire, what international and independent test agency standards the wire conforms to, what gauge the wire is and what the maximum direct current and alternating current voltages are.What do the wires on these $2.31 leads say?

author: Brutte
author_rank: Frequent Contributor
timestamp: September 02, 2016, 06:28:43 am
content: Ok, so you are testing 10A, 1000V rated probes on arduino..Don't you think you are exaggerating with safety?What about loading them at 10A and/or 1kV?? Put it under load, twist and bend and lets see if that was worth 2.31$.

author: Chumanista
author_rank: Contributor
timestamp: September 02, 2016, 07:26:42 am
content: @Brutte:I tested them in the environment I use my multimeter and in the same way that in the video I was responding to.I can do further testing in a week when I get back from my trip.@redg:They say "42C OD:3.5mm PVC 105° 1000V".@BMack:I agree that those are hobby-grade and if you do electronics as a profession (or work with something that can kill you) you should look for something more reliable.

author: Blastcap
author_rank: Regular Contributor
timestamp: September 02, 2016, 08:13:23 am
content: I think you should works on that title, needs more clickbait.

author: Chumanista
author_rank: Contributor
timestamp: September 02, 2016, 08:51:15 am
content: @Blastcap:Aren't the results surprising though?I could add "The industry HATES me!" to the end if you want...

author: vinicius.jlantunes
author_rank: Regular Contributor
timestamp: September 02, 2016, 01:19:01 pm
content: haha or "you won't believe this one weird trick to save on test probes"

author: Fungus
author_rank: Super Contributor
timestamp: September 02, 2016, 01:37:21 pm
content: I'm going with:"Man connects some probes to multimeter and you won't believe what happens next!"

author: bitseeker
author_rank: Super Contributor
timestamp: September 03, 2016, 12:47:20 am
content: They seem pretty good for the price. Perfect for the free DMMs I got.Your other short vids are cool too. I like your layer comparison on the PCB review. Subscribed.

author: zapta
author_rank: Super Contributor
timestamp: September 03, 2016, 05:22:25 pm
content: Quote from: Chumanista on September 02, 2016, 08:51:15 amMention a Big DMM conspiracy. ;-)Anyway, this is a useful and well made video. There is room in the market for low end products and high end products and these seem to be very good value low end.

author: Mechatrommer
author_rank: Super Contributor
timestamp: September 03, 2016, 06:05:45 pm
content: Quote from: Brutte on September 02, 2016, 06:28:43 amso what do you expect a probe for arduino priced? 0.231$? (thats not a typo)

author: Chumanista
author_rank: Contributor
timestamp: September 03, 2016, 06:24:47 pm
content: Thank you, everybody. I will be doing a follow-up, I just need to order another set (I need to use my DMM) and figure a simple way to get 1000V and 10A cheaply in my home lab. Any suggestions? I was thinking a transformer from mains and ATX PSU + high power resistors.

author: Brutte
author_rank: Frequent Contributor
timestamp: September 05, 2016, 07:21:30 am
content: Quote from: Chumanista on September 03, 2016, 06:24:47 pmA 230V*10A=2300W electric kettle would do (10A rms).As for 1kV, use several mains transformers wired in series. If you feed four 12V to 230V with 12V AC you should get something near 920VAC at the output. Make sure the separation in between primary and secondary of those transformers exceeds 1.5kV

author: codeboy2k
author_rank: Super Contributor
timestamp: September 05, 2016, 01:33:34 pm
content: I don't recommend 4 mains transformers in series like that. It's a low-impedance voltage source in the kilovolt range, and that's far too dangerous to be playing around with on the bench, especially for a one-off test -- test setups like this have a tendency to be thrown together quickly and not very safe.If you *DO* build it from 4-transformers in series, then put them all in a plastic box with 6 x 150k ohm, 1/2W resistors in series at the output, and an easy-to-reach switch to power it on and off. This will limit your exposure to the low-impedance transformers inside, and what's exposed at the output of the box is going to be high-impedance and current-limited to 1 or 2 mA max. The switch at the power-input side will limit your need to reach across the bench (and thus reaching ACROSS the high-voltage power supply) to plug or unplug the device into the wall socket (which are typically at the back of a bench).A somewhat safer approach might be to wire up a Cockcroft-Walton voltage multiplier. I say "safer" simply because you can drive it from a single 230V mains isolation transformer and limit your low-impedance source to the mains voltage levels (or even less, if you choose to). This way, it won't be able to deliver lethal currents into your body if you accidentally touch it. Dave has done some videos on Cockcroft-Walton voltage multipliers in the past.Attached is an LTSpice example. You can reduce the output voltage by choosing a mains input transformer with a lower secondary output voltage. You can also remove a multiplier stage too. The combination of input voltage and the number of stages will determine the output voltage.

author: MosherIV
author_rank: Super Contributor
timestamp: September 05, 2016, 01:44:39 pm
content: Talking of testing 1KV safely, I am not sure I would want to be holding the probes when measuring 1KV

author: Fungus
author_rank: Super Contributor
timestamp: September 05, 2016, 02:12:51 pm
content: Quote from: codeboy2k on September 05, 2016, 01:33:34 pmIt's very difficult to get a useful amount of current out of a Cockcroft-Walton multiplier. I once built a 20 stage CWM and a 200mA fuse on the AC mains input didn't even blow when I turned it on.10A? Not happening.

author: Fungus
author_rank: Super Contributor
timestamp: September 05, 2016, 02:17:34 pm
content: For a few quick tests you can connect a bunch of 9V batteries in a chain:

author: Kalvin
author_rank: Super Contributor
timestamp: September 05, 2016, 02:18:10 pm
content: The probes should be tested for the 1000V and 10A, but not at the same time because it is just useless. First, run 10A through the test lead and observe how it will heat up or burn. Then measure the test lead with 1000V and determine the isolation. Two separate tests.

author: saturation
author_rank: Super Contributor
timestamp: September 05, 2016, 11:00:32 pm
content: An NRTL listed, i.e., certified, set of DMM probes is tested at 10kV as set by IEC criteria, for a working voltage of ~ 1kV. A 10A rated probe is tested for ~10A at 50min, and insure it doesn't get hotter than about 50C. There are also a battery of physical endurance test to insure the probes are safe to use as rated with daily use and abuse.You can get a set of certified probes starting at about $12 for a something like Uni-T or Amprobe.

author: Macbeth
author_rank: Super Contributor
timestamp: September 05, 2016, 11:17:56 pm
content: A cheap module is available on ebay/aliexpress for 1000V DMM testing. e.g.http://www.ebay.co.uk/itm/331817421158Now don't be fooled by the insinuation that this is regulated by the mysterious top secret controller IC, the high current MOSFET, and the flyback transformer. (Yes it does have an extra primary tap that could be used for this)It's actually capable of well beyond its 1200V with no load and quickly drops to sweet FA with any kind of load (100k, 1M, etc). But yes you can dial it to 1000VDC with nothing but your 10M multimeter as a load and 12V input.I reversed the PCB and in all the world I can say the mystery DC/DC converter chip is nothing but a 555 timer(seriously!)Still it can be a useful toy to test your DMMs limits (pass/fail and I mean FAIL!! if you crank it up a little too much on a very high input impedance DMM)

author: Fungus
author_rank: Super Contributor
timestamp: September 06, 2016, 09:12:51 am
content: Quote from: Macbeth on September 05, 2016, 11:17:56 pmIt's an unregulated transformer, the output is inductive spikes.Quote from: Macbeth on September 05, 2016, 11:17:56 pmYes, seriously! Those things are not "DC converters", they're high voltage generators. All it does is feed a square wave into the transformer and then the output of that goes into a Cockroft-Walton multiplier. The 555 provides the square wave, the output voltage is whatever it is.A "DC converter" would have a feedback mechanism to the chip so regulate the final voltage. Those things don't.

author: Chumanista
author_rank: Contributor
timestamp: August 17, 2018, 04:28:16 pm
content: Has it been 2 years? It has, hasn't it? Eh, college.Anyway, this might surprise you all:

author: mzzj
author_rank: Super Contributor
timestamp: August 17, 2018, 05:55:44 pm
content: Been using same probes, for the price they do pretty well. I like the sharpish points.Durability can't be worse than Fluke silicone cables, seen about hundred pair of those fluke cables failed..

author: GreyWoolfe
author_rank: Unknown
timestamp: August 18, 2018, 12:49:49 am
content: I really don't like cheap probes. I just did the mods on my Aneng 8008 & 8009 and tried the cheep probes to measure a 9R1 resistor and they couldn't do it, The gold plated Brymen leads that I carry in my toolbag, of course, worked perfectly.