$25 Component Tester - Too good to be true?!

SteveAndBell · Jun 2, 2014

I couldn't find any previous reference to on AK so I thought I'd share something I've just stumbled across that may be handy for others...

I've been looking around for a way of measuring a wide range of capacitance as I recently discovered my existing mid-range DMMs can only measure up to a piddly low value. I had found a pretty amazing DMM at a local electronics store that did everything including up to 40,000uf and even included Bluetooth allowing connection to a Smartphone but alas it was $200 and although pretty fancy I didn't really need all the extra bells & whistles it included.

Looking at the larger filter caps in the huge stack of gear I'm yet to attack I quickly realised 40,000uf just isn't quite enough so the $200 DMM wouldn't be a great investment. I then did a Worldwide search on eBay and sorted by price to see what dedicated capacitance meters were available for as little as possible. I found quite a few that would do the trick however I also found these and for the specs & price ($25) I just couldn't resist so I bought one: http://www.ebay.com.au/itm/181395244485?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

These little modules seem to do absolutely everything I'd ever need plus more. They can handle very wide value range plus it even displays a graphic symbol or diagram of the component under test! Capacitance alone spans from 30pF-100,000uF, whoa!

Not sure if anyone else has had experience with these modules and sure they may be absolute junk but for $25 I thought it was worth the risk. Another $10 for a plastic project box & 9V battery and if all goes well I'll have an amazing little piece of test gear for under $40.

If anyone's interested I'll do a bit of a review once I receive it in a few weeks time :thmbsp:

jhoyt · Jun 3, 2014

That seems like a screaming good deal. Thanks for the heads-up on these!

ConradH · Jun 3, 2014

Not bad at all! Do you know the frequency(s) it runs at? Once you have any two parameters, say value and loss, you can convert to any other two, say reactance and phase angle. Big fancy meters don't really do much more than this one is doing, other than covering a wide frequency range and making automatic conversions. The semiconductor feature is just a huge free bonus. I wonder if you can stick some leads on it to do in-circuit measurements? Being able to do that is probably the most valuable troubleshooting tool I've got.

SteveAndBell · Jun 3, 2014

ConradH said:
Not bad at all! Do you know the frequency(s) it runs at? Once you have any two parameters, say value and loss, you can convert to any other two, say reactance and phase angle. Big fancy meters don't really do much more than this one is doing, other than covering a wide frequency range and making automatic conversions. I wonder if you can stick some leads on it to do in-circuit measurements? Being able to do that is probably the most valuable troubleshooting tool I've got.

Nah, sorry Conrad, I only just purchased mine so know nothing else about it. Even tried doing some Google searching but got nothing. It may be a complete waste of time but I thought I'd give it a go at that price.

Regarding the leads, I can't see how you couldn't add leads & clips to a raw module such as this and in fact is one of the plans I have

The onboard ZIF socket is a nice touch but adding leads would make it so much more versatile hey.

We'll see...

Chip Chester · Jun 3, 2014

It looks like there are several of these out there, and for another ten bucks you can get one with a case, battery compartment and little clip leads in addition to the ZIF socket.

Good find.

Chip

ghazzer · Jun 3, 2014

I purchased this early last year and have found it very useful. It does not always repeat with the exact same reading, but it is close enough and I always take several readings. The position of the component and the test leads can influence the readings, so don't hold them in your hand.

The tester uses an Atmega micro processor that is programmed to use the ancillary components to perform various tests.

You can read much more here. Learning to perform the self-test and the calibration is worth the visit.

I mounted the tester on a board for stability, soldered in the alligator clip leads, and attached a 9VDC wallwart. My next tester will have a better µprocessor, an updated program and a ZIF socket with micro grabber leads.

The delivered tester was a little flimsy with the display board only attached by the connector. After securing the tester to the board I cut some small dowel pieces and screwed them in as spacers to stabilize the display.

I also cut some slots to "plug" the wallwart to the board so I could stow it w/o tangling or snagging the wiring.

SteveAndBell · Jun 3, 2014

ghazzer said:
I purchased this early last year and have found it very useful. It does not always repeat with the exact same reading, but it is close enough and I always take several readings. The position of the component and the test leads can influence the readings, so don't hold them in your hand.

You can read much more here. Learning to perform the self-test and the calibration is worth the visit.

Excellent Ghazzer, thanks for the info & review. Looks like yours is one of the earlier models but obviously the same thing just with a smaller screen. Can't wait to get mine now

I've got a heap of smallish die-cast boxes I didn't end up using in a previous project so I'm thinking of building my tester into one of these. There should be enough room for a couple of sockets for leads & clips plus I should also be able to fit an 8xAA battery holder in there allowing me to run 9.6V worth of NiMHs that should last a lot longer than a standard 9V battery. We'll see :scratch2:

ghazzer · Jun 5, 2014

It sounds like some of the more recent ones have a socket so that the µprocessor can be upgraded. It can be programmed via a connector on the board.

Not my bag, but good to know.

SteveAndBell · Jun 26, 2014

WoW!

My tester arrived today so I raced home from work, tested it then got stuck into building its enclosure. I have a heap of spare die-cast boxes from another project that never eventuated plus enough misc parts in stock to build it up. Managed to get an 8 x AA holder in and filled it with eneloops. Fused it and connected it to a DC socket so I can charge the batteries using an automatic NiMH charging power supply. The non-slip foam matting & white foam pieces help insulate the battery holder from the metal box but also keeps it in place as it gets gently sandwiched in when the front panel is screwed down.

It all went together pretty well using an S-Video type 8-pin socket for testing small components however I plan to get some small/standrd banana sockets and fit them on the front panel allowing connection of leads & clips to test larger components and to enable in-circuit testing too. Might dress up the front panel a bit and add labels but that can come later.

SteveAndBell · Jun 26, 2014

Works pretty well too! Here are some screenshots of a few tests on components I had laying around...

The simple battery charging system I rigged up works perfectly and I can continue to use it while it's charging too so that's handy. So far so good. Looks like it will be a very handy addition to the test gear... and sooo cheap to boot! Highly recommended so far but I suppose time will tell.

toxcrusadr · Jun 26, 2014

Gee, and it does ESR and everything. If it's actually any good, that's an amazing deal.

Kahoona · Jun 26, 2014

Wow! What a find! I must have one. I am amazed at the mods too. Thanks.

spkrdtr · Jun 26, 2014

This one is even lower in price and available here in the states.

http://www.ebay.com/itm/New-Transis...230?pt=LH_DefaultDomain_0&hash=item27e6149976

ghazzer · Jun 26, 2014

Please check it out and tell me how well it reads small resistors (1Ω or less) and small caps (20 or 30 pƒ), and does it get the same value repeatedly. Mine is inconsistent and it would be great to have one that would give repeat readings that were closer.

Great work on the enclosure. I have found it very convenient to use test leads with mini grabbers.

spkrdtr said:
This one is even lower in price and available here in the states.

Make sure that the cheaper one has the M328 chip and a vetted program. That one looks like an older version.

Dukiedook · Jun 26, 2014

The only problem I would see with these units is testing caps for tube units you would not be able to test the caps at operating voltages. It looks like it would work for simple pass/fail tests though.

SteveAndBell · Jun 27, 2014

Woke up this morning and decided to add the banana sockets, label the buttons and dress it up to finish it off completely. The leads are multifunction with screw-on ends allowing banana plugs, probes or clips to be attached.

Now, onto actually using it :scratch2:

westend · Jun 28, 2014

Sexy as hell, hope it works wonderfully for 'ya.
Nice work on the construction!

jaymanaa · Jun 28, 2014

Hope this hasn't been answered, but have you compared accuracy to a known good meter. This is incredible man, I gotta have one.:yes:

Binkman · Jun 28, 2014

I agree we need some comparisons. I'm all for diy if it's in the use range as noted or just good for the small stuff, too. Need someway to hang it on the hardware board or wall with the other tester stuff

s-petersen · Jun 29, 2014

I have a similar, older one of these.Once in a while it makes a mistake.
I have had some components misread,but overall it's accurate.
no affl
http://www.ebay.com/itm/Transistor-...ltDomain_0&hash=item338d8c0785#ht_1971wt_1304

$25 Component Tester - Too good to be true?!

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