EEVblog #229 - IET DE-5000 LCR Meter

[sdttn]

The ICs from cyrustek. ES51919/ES51920

http://translate.google.com/translate?hl=en&sl=auto&tl=en&u=http%3A%2F%2Fwww.crystalradio.cn%2Fbbs%2Fthread-217337-1-1.html

http://www.cyrustek.com.tw/product-2-6.htm
http://www.cyrustek.com.tw/spec/ES51920.pdf

Sorry, was that a trade secret?

[Greg J]

no shielding inside, do a gsm test ! fluke style !

[grenert]

The ICs from cyrustek. ES51919/ES51920

Good catch!  A lot of the IET manual comes straight from the Cyrustek datasheet, too.

I'm surprised they bother to cover it up.  How many off-the-shelf LCR chipsets can there really be 

[Flavour Flave]

We could do an open source LCR meter with this chip. It would more realistic to do, unlike the open source multimeter project some people tried on this forum because a lot of the variables have been removed(features we need have been decided on the chip). Just need to provide front end, gui and power and maybe data iO.

[BravoV]

The ICs from cyrustek. ES51919/ES51920

Ha..ha.. thats a great finding ! Thanks !

From that links, the Mastech's pcb shot like below showing a quite resemblance of that de-5000 board isn't it ?

Sorry, was that a trade secret?

Naah.. nothing to worry about, especially with these days product that are using commodities off the shelf chips, its just matter of time, people will discover what they're using.

Custom asic is the only way to prevent people to peek around, but that will be another pricing league.

[Psi]

The sound and video quality on the first official blog in the new lab is perfectly fine.
No echo or anything bad at all.

Probably don't need the sound absorbing panels.

[Drirr]

It is similar to APPA703, take a look inside https://picasaweb.google.com/cada.david/APPA?authuser=0&feat=directlink

[mikeselectricstuff]

We could do an open source LCR meter with this chip. It would more realistic to do, unlike the open source multimeter project some people tried on this forum because a lot of the variables have been removed(features we need have been decided on the chip). Just need to provide front end, gui and power and maybe data iO.

That would depend on being able to source the chip in sensible quantities.
How many potential LCR meter users would care about it being Open Source?
Calibration will also be an issue for any DIY approach, although this could maybe be solved by someone with an accurate meter offering a set of cheap parts that  have been accurately measured.

[EEVblog]

The sound and video quality on the first official blog in the new lab is perfectly fine.
No echo or anything bad at all.
Probably don't need the sound absorbing panels.

For some reason there is a faint but noticeable air-con type drone noise in the first clip, but not the rest of the clips.
Not sure why.
But yeah, sound in there isn't too bad at all.

Dave.

[HLA-27b]

For some reason there is a faint but noticeable air-con type drone noise in the first clip, but not the rest of the clips.
Not sure why.
But yeah, sound in there isn't too bad at all.

Dave.

It was noticeable. Maybe the mike was picking up vibrations from the structure and not from the air.

[Psi]

For some reason there is a faint but noticeable air-con type drone noise in the first clip, but not the rest of the clips.
Not sure why.
But yeah, sound in there isn't too bad at all.

Dave.

It was noticeable. Maybe the mike was picking up vibrations from the structure and not from the air.

I only notice it now that you've said. It's really nothing to worry about imho.

The previous lab had all the birds in the background sometimes, and they were far far worse.

[LEECH666]

Hehe ... I couldn't help but to think of this video of made by Mike when you mentioned the little suitcase the LCR meter comes in.

Skip to 5:35 in the video.

http://youtu.be/6td9kVKWGFw

"[...] you're just gonna look like a dick."
"[...] pcb drill [...] sorted. *thumbs up*"
Man this is outragious, in funny way.

Cheers from Germany,
Florian

[amspire]

Looks like the Mastech MS5308 that appears to use the same chipset as the DE-5000 is available for about $250 delivered, and that includes the Kelvin clip, the SMD tweezers and the interface cable to the PC.

http://www.aliexpress.com/fm-store/209471/0-511363183/New-MS5308-Portable-Handheld-AutoRange-LCR-Meter-100Khz-fit-FLUKE-dual-display.html

Best accuracy for L and C seems to be 0.5% rather then 0.3%. For some reason, it requires 8xAA batteries and a 9V battery. Sounds like they wanted to avoid any kind of switching power supply.

[grenert]

That Mastech has got a strange look to it!  It appears to be styled after the old Tektronix THS series of portable oscilloscopes.

[tinhead]

the major problem with Mastech is Mastech itself.

look at the specs on Mastech website:

L: 200uH~~2000H
C:20000pF~~2.0mF
R:20.000?~~200.0M?
 
then check (most) sellers:

L: 200uH~~2000H
C:2000pF~~2.0mF
R:20.000?~~200.0M?

and finaly Cyrustek:

L: 20.000 ?H ~ 2000 H
C: 200.00 pF ~ 20.00 mF
R: 20.000 ? ~ 200.0 M?


Luckily IET specs/manual is very clear.

[mikeselectricstuff]

Hehe ... I couldn't help but to think of this video of made by Mike when you mentioned the little suitcase the LCR meter comes in.

Skip to 5:35 in the video.

http://youtu.be/6td9kVKWGFw

"[...] you're just gonna look like a dick."
"[...] pcb drill [...] sorted. *thumbs up*"
Man this is outragious, in funny way.

Not quite the same situation - you buy a small scope primarily because it's small, and you will mostly be using it away from the bench. For gear that is mostly used on the bench, and comes with some specific accessories, a hard case is a perfectly reasonable solution, although in the case of that LCR meter, I'm not sure there would be room for a mains adapter with a UK 13A plug. 

[Bored@Work]

A hard case is ok if the instrument is very delicate and expensive or if it is rarely used. Then the case helps to store and protect it. But if it is a garden-variety instrument for the bench it'll go into a drawer or on the shelf. Then an extra case is just annoying, because you don't want having to unpack it and set accessories like the charger up every time you use it.

[LEECH666]

Yes Mike, I agree completely. It just reminded me of your video.

Cheers,
Florian

[king.oslo]

Hello there,

I asked IET why they decided to leave out input protection and shielding. I thought that the response was a interesting:

IETLabs said:

Oversights.
However, to my knowledge no units have come back blown.
The units performance, even without shielding, holds up to some of our bench top instruments.

What do you think?

Dave, will you give us GSM-test?

Thanks.

Kind regards,
Marius

[alm]

I wonder if this was an outsourced design and this means they forgot to check the input protection/shielding. I find it hard to believe that an experienced design engineer would just plainly forget about protecting inputs.

[king.oslo]

Alm,

This is what Dave Jones wrote as part of his amazon review of the meter:

I talked to an IET tech before I bought it and asked how they achieved this price. He quickly said Taiwan. They looked a long time to find a meter that they felt lived up to the IET reputation. They finally found this meter and after extensive testing partnered with them to sell this meter.

Sounds like you are right.

Do you reckon we should be concerned with these issues?M

[amspire]

Do you reckon we should be concerned with these issues?M

If I was buy a LCR meter for myself and I was given a choice between input protection or accuracy, I would choose accuracy.

If I was the manager of a company buying a bunch of LCR meters for general use, I would get ones with input protection.

If you can trust yourself to never attempt to do in-circuit testing (particulaly if the circuit is live), testing charged 400VW electrolytics and to never plug the LCR meter into the mains, then having no protection is not a huge problem.

Richard.

[robrenz]

Alm,

This is what Dave Jones wrote as part of his amazon review of the meter:

I talked to an IET tech before I bought it and asked how they achieved this price. He quickly said Taiwan. They looked a long time to find a meter that they felt lived up to the IET reputation. They finally found this meter and after extensive testing partnered with them to sell this meter.

Sounds like you are right.

Do you reckon we should be concerned with these issues?M

Just for clarity and protecting Dave's reputation that quote was from my post about the DE-5000 not Dave Jones.

[septer012]

Bought one.   Circuit board version 8.   

They added a diode (D5) reverse polarity in parallel to the 9 volt.  I put in batteries didn't start up at all. Got hot from short on D5.  Yanked D5 out and worked fine.

From another thread this power supply schematic was posted by dfmischler, not exactly the same references but pretty close to the same power supply.  It will help you if you have issues as well:https://www.eevblog.com/forum/testgear/ms-5308-power-supply-issues/msg189878/#msg189878] [url]https://www.eevblog.com/forum/testgear/ms-5308-power-supply-issues/msg189878/#msg189878[/url]

D5 is not in the schematic.

[David Hess]

We could do an open source LCR meter with this chip. It would more realistic to do, unlike the open source multimeter project some people tried on this forum because a lot of the variables have been removed(features we need have been decided on the chip). Just need to provide front end, gui and power and maybe data iO.

That would depend on being able to source the chip in sensible quantities.
How many potential LCR meter users would care about it being Open Source?
Calibration will also be an issue for any DIY approach, although this could maybe be solved by someone with an accurate meter offering a set of cheap parts that  have been accurately measured.

Analog Devices makes some impedance converter/network analyzer ASICs which would be easier to source and have full documentation that would be suitable.  I have considered doing this myself.

http://www.analog.com/en/rfif-components/direct-digital-synthesis-dds/ad5933/products/product.html
http://www.analog.com/en/rfif-components/direct-digital-synthesis-dds/ad5934/products/product.html