EEVblog #99 – $100 Multimeter Shootout – Extech Amprobe BK Precision Ideal UEi Uni-T PART 1of2Posted on July 11th, 2010 21 comments
PART 1 of 2
Dave compares six $100 Multimeters:
BK Precision BK2709B
21 responses to “EEVblog #99 – $100 Multimeter Shootout – Extech Amprobe BK Precision Ideal UEi Uni-T PART 1of2”
I couldn’t wait to watch the 100$ shootout so I watched it on YouTube before it posted at EEVBlog. I could tell this one was the hardest for you to film, edit and publish. It must have been rough. Well here’s to you Dave: Hip-Hip Cheers! Hip-Hip Cheers! And a big “Thanks you”.
Nice review there!
And i have to agree on the BK precision one. If only the thing wouldn’t beep so much! The UNI-T is quite a good choice too considering how cheep it is for all the features.
That particular UNI-T model is just 40 EUR or 50$ *shipped* from china in ebay. I doubt the others are available such cheaply there.
They have a higher end model that is ~$100 with shipping but given the quality of the internals shown here and the chance it is “slow” like the one here I wouldn’t go for it without similar indepth review, so overall the best decision is probably to save for a Fluke or go with the cheapest thing that has what one needs.
great job on the review. sadly i had to run my grandmother to the hospital for a couple of hours half way through the first video but i got back and finished it up about 12:00 am here my time.
i do have a few questions though….
1) what does the shunt affect in measuring things?
2) i know that the meters have different cap ranges. what should be the lowest and highest possible range needed for an electronics hobbiest that is just starting out and is only dealing with DC applications?
3) With the Extech EX505 showing some bad component lay out and such and there was a few shoots of the more expensive EX530 in the forums, does this mean Extech is not the well made products we had come to believe?
4)i know the BK was able to light the LED which is great bc i think the spec is 3.5 test volt, but it doesnt show on the screen. how big of a problem is that for someone like me? i mean is it really needed or does it serve a serious purpose?
thanks and again great job.
Dave will probably come in and give you better answers, but I can help you out in the meantime:
1) The current shunt is a low value resistor, such as 0.01ohms that goes in series with the circuit you wish to test current through. Using Ohm’s law, you can calculate current by measuring the voltage drop across the shunt. In an ideal world, you want the current shunt to be 0 ohms, but then there would be no voltage drop and hence no way to measure it. Dave made a project with much lower resistance current shunts to increase accuracy. Note that the lower the resistance of the load, the lower the resistance your current shunt must be, or you will greatly change the circuit and accuracy of your measurement.
2) For cap ranges, lower is better. It’s not like you need to be measuring large electrolytics (as they are usually labelled). You want something that ideally goes down to a few pF, so that you can pick up any random ceramic or poly cap and measure it. 10pF to 10nF is good, 1pF to 100nF is great. Anything better than 10% accuracy is fine for a hobbiest and generally acceptable without buying a quality LC meter)
4) If it doesn’t display on the screen, then the only thing you can know about the LED is the polarity, not the forward voltage. It really depends on what you are doing. It’s not a problem for me, because if I was doing something serious with an LED, I would have a specific part with a datasheet, and just use the DMM to check polarity. For any other LED I find (bread and butter red/greens), I would probably just add resistance to get it to draw about 20mA and call it a day.
I always enjoy this blog, however it seems that Extech gets a lot of good comments despite having one product after another have SOME kind of problem!
It looks to me like they are inconsistent at best despite having good specs and SOME good qualities, but overall not worthy of the praise you give them.
I applaud your efforts. This was a great shootout! I sincerely appreciate all your time invested on this topic. I for one think it is great work.
Thank you again for a fine job well done.
I was sorry to hear that the Extech does not work with LEDs. Until I saw your blogs I didn’t know that any meters had this LED lightup and forward voltage measurement capability built in. This would be a huge time saver. I usually have to breadboard a test circuit and test LEDs manually. I really want this feature on my next DMM.
More and more I think I will just save up for the Fluke 87 V.
For the LEDs, I built one of these years ago: http://www.robotroom.com/LEDTester.html. Mine uses a two way female header socket, which is only good for leaded LEDs. I only ever use 3mm, 5mm, 0805, and 1206 LEDs. The LEDs always have markings on them, and I use this for checking colour when I mix them up.
Dave, Fantastic review. I think your efforts will have a positive effect on build quality from the companies (like Extech) who seem to want to listen. One thing I noticed was that there seemed to be a solder bridge across a couple of the pins on the main processor of the BK precision meter. Must not have been important pins.
That ideal meter is a piece of garbage. Jaycar market that brand as being as good as fluke. I’m not surprised it’s about as good as any other meter they sell there.
Was I the only one who saw a solder short on the bk precision’s Main IC (top left corner in the video) or was that just some light pollution that caught my eyes off gaurd?
If It was a short I could not figure out why Dave neglected to mention it. Although the bk was my favorite the need to watch their SMT line better.
A few years back,I worked at a place where
they bought a number of UNI-T meters.
(I think they were similar to the one tested)
They had some annoying habits:-
After applying the probes to do a test, the
thing took so long to give a reading,that if
we were looking for something that was only
present for several seconds,it would miss it.
For instance,if you were checking a cable for
continuity,it was necessary to slow down your
testing so the meter could keep up!
Another beaut trick was how the resistance
range became inaccurate when the battery
started to fail(Before any indication of batt low on the display).
Finally, the thing would turn itself off in
the middle of a measurement!
What is it with these modern DMMS? Even the
new Flukes do this! ( Although you can turn it off)
My old Fluke 77 will turn off if it isn’t
measuring anything,but not in the middle of a
While I was thinking about this,I dragged my
77 out,only to discover it isn’t working on
the ohms range–bummer! I hope I don’t have
to replace it with some cheap crud!
Does anyone know why the BK2709B displayed the word “Hold” when it turned on, but it doesn’t have a hold feature?
The ‘Extech EX505′ is really an OEM meter with custom colours, have a look at the ‘IP67 True RMS Autoranging Cat IV DMM’ in Jaycar’s catalogue (Cat: QM-1549). It is the same unit, and cheaper to boot.
I want that T-shirt slogan on a mug! I love Dave’s Tees…
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