Author Topic: High-precision L/C Inductance Capacitance meter Design  (Read 25325 times)

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Online Mechatrommer

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Re: High-precision L/C Inductance Capacitance meter Design
« Reply #25 on: December 10, 2010, 04:07:06 pm »
another poison that lands on my skin...
https://www.eevblog.com/forum/index.php?topic=1392.0;topicseen

its good to have a FG, but i think why not i get more extended wave by getting AWG. i've looking at the rigol DG1022, one thing that catch my eye is "seamless connection with existing DS series DSO, which i already got. but yet, i still havent seen any hard negative or positive feedback on it. the negative comment i saw before is not really "hard" except saturation's post about a "translated chinese site" link, but then, i dont fully get what the guy tried to explain.

maybe with this AWG, i dont have to worry about upgrading from a simpler FG if i want to extend my working scope, eg RF (which i'm currently working on) or "super high powered" audio amp (which i will be planning, maybe).

how about USB "nano-type" AWG? are they good/accurate?
« Last Edit: December 10, 2010, 04:12:31 pm by shafri »
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Offline saturation

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Re: High-precision L/C Inductance Capacitance meter Design
« Reply #26 on: December 10, 2010, 07:43:00 pm »
Hi shafri,

A big difference in an AWG over FG is cost.  The prices are dropping, but good ones still cost far more than a DDS FG. 

The $600 Rigol AWG review from the Chinese website was written in 2008, maybe Rigol has improved on these issues; here's the cleaned up translation in the author's words:

Superimposed white noise limited to 5MHz, pulse only support to 3MHz, frequency accuracy limited to 100ppm
ch2 is unequal {to Ch1}, any generated waveform limited to 1kpts, 10bit; output amplitude not more than 3Vpp
Unit crashed during testing
ch1 channel maximum output setting at 23.98dBm but measured output was only 15dBm, until the occassional restart made it output properly
the magnitude of the output flatness is very bad; biggest difference 6Vpp
when using the Sweep function, flatness decreased, while the manual scan no effect on the flatness.

-----

A recent comment on the Rigol at eevblog:
https://www.eevblog.com/forum/index.php?topic=197.msg1892#msg1892

the Instek 1003 has rated stability output of < 20ppm and wholly stable across all its output range, but it has only 1 channel.  The Instek 1003 is $150, you can get a Hantek USB generator for the same money, but how accurate is it in terms of its waveforms and stability? 

http://compare.ebay.com/like/150439450643?var=lv&ltyp=AllFixedPriceItemTypes&var=sbar&rvr_id=182556568013&crlp=1_263602_309572&UA=WXF%3F&GUID=ad8419371280a02681b38503ffc8ed2c&itemid=150439450643&ff4=263602_309572

AWG come in difference price ranges, so how can there be so much variation? One large cost is making output stable across any condition an arbitrary wave can exist:

http://www.tti-test.com/1/arb-infotour-tti/arb-infotour.htm


another poison that lands on my skin...
https://www.eevblog.com/forum/index.php?topic=1392.0;topicseen

its good to have a FG, but i think why not i get more extended wave by getting AWG. i've looking at the rigol DG1022, one thing that catch my eye is "seamless connection with existing DS series DSO, which i already got. but yet, i still havent seen any hard negative or positive feedback on it. the negative comment i saw before is not really "hard" except saturation's post about a "translated chinese site" link, but then, i dont fully get what the guy tried to explain.

maybe with this AWG, i dont have to worry about upgrading from a simpler FG if i want to extend my working scope, eg RF (which i'm currently working on) or "super high powered" audio amp (which i will be planning, maybe).

how about USB "nano-type" AWG? are they good/accurate?

Best Wishes,

 Saturation
 

Online Mechatrommer

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Re: High-precision L/C Inductance Capacitance meter Design
« Reply #27 on: December 11, 2010, 01:34:23 am »
thanx saturation.

how serious is the 100ppm inaccuracy? 50ppm (90days), 100ppm within a year, what? is this figure is going up and up in time? so within 5 years maybe it will be 500-1000ppm inaccuracy?
how serious is the output flatness? what is output flatness? sorry, never own one of this toy.

http://cgi.ebay.com.my/AT8602B-Digital-Function-Signal-Generator-0-2MHZ-2MHZ-/320451191042?pt=BI_Signal_Sources&hash=item4a9c612102 an Atten function generator, half the price of AWG. So roughly i'll be paying double, one for function, and one for arbitrary. will do more reserach on this.
« Last Edit: December 11, 2010, 01:52:40 am by shafri »
if something can select, how cant it be intelligent? if something is intelligent, how cant it exist?
 

Offline saturation

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Re: High-precision L/C Inductance Capacitance meter Design
« Reply #28 on: January 03, 2011, 04:38:39 pm »
Its hard to say how serious, that's why you have to trust the makers to do the right accelerated aging and testing. The specs quoted you mentioned in bold are from the 1022 manual.

As for the Instek, it said the 1003 specs were:

Stability & Accuracy each at
+/- 20ppm

Aging
+/- 5ppm/year

Flatness simply means the amplitude output will not change with frequency and will maintain the same Vac p-p.


Yes, that drift and per waveform stability is higher compared to the Instek.



thanx saturation.

how serious is the 100ppm inaccuracy? 50ppm (90days), 100ppm within a year, what? is this figure is going up and up in time? so within 5 years maybe it will be 500-1000ppm inaccuracy?
how serious is the output flatness? what is output flatness? sorry, never own one of this toy.

http://cgi.ebay.com.my/AT8602B-Digital-Function-Signal-Generator-0-2MHZ-2MHZ-/320451191042?pt=BI_Signal_Sources&hash=item4a9c612102 an Atten function generator, half the price of AWG. So roughly i'll be paying double, one for function, and one for arbitrary. will do more reserach on this.

« Last Edit: January 03, 2011, 04:40:37 pm by saturation »
Best Wishes,

 Saturation
 

Offline grenert

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Re: High-precision L/C Inductance Capacitance meter Design
« Reply #29 on: January 21, 2011, 02:11:02 am »
This is getting way off topic, but the Velleman PCGU1000 looks like a promising inexpensive (about $200) USB DDS FG:
http://www.vellemanusa.com/us/enu/product/view/?id=523616

One user did some extensive testing with good results:
http://forum.velleman.eu/viewtopic.php?f=11&t=2041

The same guy posts some additional tests here:
http://www.diyaudio.com/forums/equipment-tools/158515-function-generator.html

For an LCR meter (back on topic  :)), I built one of these:
http://www.m3electronix.com/featureslcr.html
 

Offline DJPhil

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Re: High-precision L/C Inductance Capacitance meter Design
« Reply #30 on: January 21, 2011, 09:38:24 am »
This is getting way off topic, but the Velleman PCGU1000 looks like a promising inexpensive (about $200) USB DDS FG: . . .
Very interesting!
Their SDK is in revision 5, with examples in Delphi, VB6, and VB2008 Express. Looks pretty good for low frequency work. I'd pretty much settled on the 1003, now I'm not so sure.  :-\

For an LCR meter (back on topic  :)), I built one of these:
http://www.m3electronix.com/featureslcr.html
This looks like the most solid kit I've seen so far. For some reason their sales page is broken, so I don't even know what they're asking price is!
I'd like to know more about what you think of your M3. I've been skating by without a way to measure inductance (easily) for too long, and now it looks like I'll be getting into RF soon, so the added features would prove useful.
Is it awesome enough that I should send them an email asking after a kit? :)
 

Offline saturation

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Re: High-precision L/C Inductance Capacitance meter Design
« Reply #31 on: January 21, 2011, 12:33:33 pm »
Impressive results on the Velleman!  Sorry I did not see it sooner.  I don't know if the Instek 1003 will be equally as good as I don't have the same lab equipment as the tester.  The harmonic distortion of the sine wave output at 100kHz is at the noise floor of the Rigol 1052E. -50dB, still higher than the spec reported for the 1003 spec of -55dB.  Nevertheless, the Velleman is better than the Instek as it does AWG for very low cost.

http://www.velleman.be/downloads/0/information/pcgu1000_review_cknight.pdf

Its not too far off topic, this thread discussed how you can make a simple ~0.5% LCR meter on-the-fly so long as you have a function generator and scope to measure L or C.  

https://www.eevblog.com/forum/index.php?topic=1869.msg25868#msg25868

This is getting way off topic, but the Velleman PCGU1000 looks like a promising inexpensive (about $200) USB DDS FG:
http://www.vellemanusa.com/us/enu/product/view/?id=523616

One user did some extensive testing with good results:
http://forum.velleman.eu/viewtopic.php?f=11&t=2041

The same guy posts some additional tests here:
http://www.diyaudio.com/forums/equipment-tools/158515-function-generator.html

For an LCR meter (back on topic  :)), I built one of these:
http://www.m3electronix.com/featureslcr.html
« Last Edit: January 21, 2011, 05:24:00 pm by saturation »
Best Wishes,

 Saturation
 

Offline grenert

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Re: High-precision L/C Inductance Capacitance meter Design
« Reply #32 on: January 21, 2011, 06:17:01 pm »
This looks like the most solid kit I've seen so far. For some reason their sales page is broken, so I don't even know what they're asking price is!
I'd like to know more about what you think of your M3. I've been skating by without a way to measure inductance (easily) for too long, and now it looks like I'll be getting into RF soon, so the added features would prove useful.
Is it awesome enough that I should send them an email asking after a kit? :)

It is indeed awesome  :)
The things I like about it are:
Really comprehensive, high-resolution measurements of capacitors and inductors.
Resistance down to 1 milliohm with 4-lead measurement (but see below).
Ability to measure power transformers and chokes.  It'll even figure out the secondary voltage on an unknown transformer!  I have also built the LC meter from AADE (http://aade.com/lcmeter.htm), another awesome kit.  However, it only measures at higher frequencies (from tens-hundreds of thousands of Hz) and can't do low-frequency measurement needed for big iron cores.  The M3 measures at several different (user-selectable) frequencies from 100/120-15000 Hz.  On the other hand, when I just want to match capacitors (by capacitance), I actually go to the AADE first, because it's so quick to use.
Really nice display and printed metal case.  The case is pre-drilled, too, which is a big deal for a guy like me with POOR drilling skills.
SMALL for all it can do.  Its capabilities seem like something from a big rack-mount meter.

Some negatives (like Dave, gotta point out the negatives too, even when you love a product  ;) ):
Little clicky buttons are perfectly functional, but I'd prefer more substantial ones.  That would probably make construction a little harder.
You have to make the four leads yourself out of miniclips and mini-coax cable.  It wasn't easy.  The task would be a lot easier with a high quality soldering iron with a fine tip.
I thought that the attachment to the clips was a little bit tenuous because there is no strain relief, and the central wire in the coax is pretty stiff.  I ended up making another set using Pomona 4555 minigrabbers which also don't have strain relief, but they have less play in them, and the wire insertion is at a better angle.  M3 was very helpful in assisting me with that.  I also ended up building their Kelvin leads (what a time saver!).  But you still need 4 leads for transformer measurements.
You need a separate power supply.  I would really love if it could run on internal batteries.

I bought mine about 2 years ago for $175.  The Kelvin lead kit was about $40.  If you're mostly interested in RF inductors, then you might be able to go with the AADE, which is only $100 for the kit.

Cheers.
 

Offline tinhead

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Re: High-precision L/C Inductance Capacitance meter Design
« Reply #33 on: January 22, 2011, 01:53:56 am »
For an LCR meter (back on topic  :)), I built one of these:
http://www.m3electronix.com/featureslcr.html

from specs point of view look nice, but for me no go. These guys are living still in the 80's :

Upgrades from earlier versions are provided free to the original purchaser.
To receive the latest revision you must send your LCRZ meter to M-Cubed Electronix for reprogramming


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I want to reach out with something other than these prehensile paws and feel the solar wind of a supernova flowing over me.
 

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Re: High-precision L/C Inductance Capacitance meter Design
« Reply #34 on: January 22, 2011, 02:23:38 am »
from specs point of view look nice, but for me no go. These guys are living still in the 80's :

Upgrades from earlier versions are provided free to the original purchaser.
To receive the latest revision you must send your LCRZ meter to M-Cubed Electronix for reprogramming

If they released firmware files for those that have the equipment to program the processor their product would be cloned and on sale in China in a couple of weeks. In the 80's it would have been less of an issue.
 

Offline DJPhil

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Re: High-precision L/C Inductance Capacitance meter Design
« Reply #35 on: January 22, 2011, 06:29:32 am »
It is indeed awesome  . . .
Thanks for all the info!
Sounds like the M3 kit is perfect for me, so I sent an email.
I'd seen the AADE kit as well, and it too looks good. It'll be my fallback if the M3 guys don't respond, as I really like the extra features (and range) in the M3.
The drawbacks seem easily tolerable to my temperament. I'm even likely to try to make a membrane to go over the buttons, just for fun.
It'll be nice to have a proper tool for the job instead of trying to get things measured with a multimeter and a 555 circuit all the time.
Thanks again for helping fill in the blanks.  :)
 

Offline grenert

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Re: High-precision L/C Inductance Capacitance meter Design
« Reply #36 on: January 22, 2011, 08:22:06 am »
from specs point of view look nice, but for me no go. These guys are living still in the 80's :

Upgrades from earlier versions are provided free to the original purchaser.
To receive the latest revision you must send your LCRZ meter to M-Cubed Electronix for reprogramming



Well, the current firmware is the same as when I bought mine 2 years ago, so it's plenty mature.  If it makes you feel any better, just pretend it's not upgradeable at all, like most meters ;D
 

Offline DJPhil

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Re: High-precision L/C Inductance Capacitance meter Design
« Reply #37 on: January 22, 2011, 06:01:00 pm »
Sad news from M3:

Quote from: Mike - KC8WR
I am sorry to say that M-Cubed Electronix, Inc. ceased business operations on June 30, 2010.  The LCRZ meter kit is no longer available.
The web site information is there only while we attempt to sell the business.

Looks like I missed the boat on this one. I'll be keeping an eye on them though, as I'd love to see their meter go back into production.
 


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