New LCR meter from Extech - LCR200

[zaoka]

Looks like Extech released new LCR meter..

http://www.extech.com/instruments/product.asp?catid=56&prodid=692

It cost $259 on eBay...

[robrenz]

I bought this one from IET Labs and I am very impressed. its a little more expensive but it has tighter accuracy and it uses 4 wire kelvin style  connections on its tweezers and gator clip plug ins.
http://www.ietlabs.com/digibridges/de5000-lcr-meter.html

[Ronnie]

Do you think IET Labs DE-5000 is more than enough for audio design? Right now I'm considering the Agilent U1733C (US$400) though I don't have a budget yet.
Lowest capacitance range is only 200 pF in contrast to 20 pF for Extech LCR200 & Agilent U1733C.
DE-5000 is also available at Amazon http://www.amazon.com/IET-DE-5000-Handheld-LCR-Meter/dp/B005EMT8PC

[amspire]

The DE-5000 is probably more then you need for audio work, unless you have a reason for needing accuracy for a particular reason.

200pF range is fine. 

For pico farad level readings for 2 wire capacitors, accuracy only makes sense if the test rig is precisely defined, and the capacitance will be different in an actual PCB.

So the Agilent 20pF range is probably more for matching capacitors, or checking the tolerance range in a batch, rather then for measuring the actual capacitance value. If you need capacitors in the pf range, you will probably pick the final value by testing the board, rather then by design.

The only way to get accurate sub-picoFarad readings is to use 3 terminal capacitors where one terminal is a shield that encloses the capacitor.  With 3 terminal capacitors, you can measure accurately to attoFarads with the appropriate gear.

In fact the standard for Capacitance is usually based on the  LAMPARD-THOMPSON CALCULABLE CAPACITOR (double thumbs up to CSIRO in Australia) which is usually about 0.5pF and I think accuracies have been achieved to better then 1 part in 10^-15. That means measuring down to billionths of an attoFarad.

Beat that, Agilent! Back to the old transformer bridges and heaps of volts.

If you are designing audio boards for manufacture, then your design should aim at not needing better then 1% resistors, 5% capacitors, and if possible, no accurate inductors. If for some reason, you need capacitors better then 1%, then you will have other issues to deal with, like the change in capacitance with frequency, the thermal and long term drift of capacitance, and the effects of the internal inductance and resistance of the capacitor.

Richard.

[grenert]

IET is the current incarnation of General Radio, the longtime experts in precision standards and measurement, so I would tend to trust their stuff.  You can see it ranges up to equipment costing many thousands of dollars.  They are definitely a serious company that makes professional tools.

I note in the Extech LCR200 manual that many of the specs are only met "after calibration."  Since most folks are not equiped to do this, you can really only expect to get their published accuracy after paying for calibration, which eliminates the price advantage.  If you don't get it calibrated, who knows what the accuracy is...

[jarvis]

I think that "After calibration" means Open/Short calibration finished

[ejeffrey]

For instance at work I have an AH2500 capacitance bridge that measures capacitances of around 1 pF with 5 aF resolution.  With a 1 kHz excitation frequency.  So much for the myth that you need high frequency to measure small capacitances...  You do need a 3 terminal bridge, however.

[amspire]

For instance at work I have an AH2500 capacitance bridge that measures capacitances of around 1 pF with 5 aF resolution.  With a 1 kHz excitation frequency.  So much for the myth that you need high frequency to measure small capacitances...  You do need a 3 terminal bridge, however.

I am very jealous. What was the reason you ended up with a AH2500?

And can anyone actually calibrate it?  Who has a 5ppm accurate standard capacitor?

Richard.

[jarvis]

Anybody review the Extech LCR200 or DE-5000 ?

[robrenz]

I did take mine apart to see the build quality and I was very impressed. it is immaculate inside. The main chip has an epoxy smear to cover the identification.  There are very few discrete components on the board compared to other designs I have seen.  I was interested to see if it had separate drive and sense circuitry to the built in component test connectors and the banana jacks.  It does, including the banana jacks are split halves like the fluke 2x4 kelvin connections on the 88xx series of bench meters. I have a Fluke 8846A on order and it is being built at Fluke Everett WA as we speak.  I will see if the 2x4 kelvin probes of the fluke will fit and work on the DE-5000 when it shows up. I have no experience with LCR meters other than the DE-5000 but here is my opinion of it.  The readings settle very quickly and are very repeatable.  I bought both the tweezers and the (alligator lead  test fixture, not on the website any more).  both have drive and sense leads kept separate as far as possible. I found the resistance (not DCR) extremely consistent and fast with .001 Ohm resolution. When you do the CAL procedure it compensates for all the impedance's of your fixture. I was able to get consistent repeatable Milli Ohm measurements and got good agreement with calculated resistance per inch of solid 20 gage wire. I did not buy it to measure resistance but the high resolution low ohms is very handy for contact resistance measurement. I measured every type and size of capacitor I own. Most gave very fast stable readings but some would require a few seconds to settle to a stable reading. Inductors behaved similarly.
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.  That and the fact that you can pay for 3 different levels of calibration, (2 include the test data) told me I could trust the stated accuracy.

I know this sucks as a review but some of it may be helpfull.

[zaoka]

No pictures? 

[Ronnie]

The main chip has an epoxy smear to cover the identification.

Do you have a pix of the main chip? Will there be a reliability issue smearing an IC with epoxy?   

[saturation]

I didn't know such machines were commercial:

http://www.andeen-hagerling.com/ah2500a.htm

FWIW, a NIST commonly uses 1kHz for impedance metrology of capacitors, but there is no standard frequency.

http://www.nist.gov/calibrations/impedance.cfm

https://www.eevblog.com/forum/index.php?topic=3440.msg45910#msg45910

For instance at work I have an AH2500 capacitance bridge that measures capacitances of around 1 pF with 5 aF resolution.  With a 1 kHz excitation frequency.  So much for the myth that you need high frequency to measure small capacitances...  You do need a 3 terminal bridge, however.

[midnight]

Just picked up an LCR200 yesterday...  I'll pull it apart and take some pics this weekend.

So far I am pleased with the features and speed of the LCR200.  I have a few Extech multimeters (an EX570 and a cheaper one).  The speed my Extech multimeters does not impress me.  In fact I think they are very weak in that area, but this LCR200 is quite impressive.

So far the only complaints I have about the LCR200 is;
 - The buttons are squishy
 - There is no shock absorbing liner around the case.  Feels like it might break if dropped.

I'll post more with the pics, but I feel it's going to get good reviews... especially with the frequency range and speed of readings.