Mastech MS5308 LCR meter with ESR measurement - on discount at the moment

[Fraser]

Hi Lo-tse,

I must agree, the provided Mastech manual is a poor document and missing information such as the important calibrate button !

When I received my unit I immediately downloaded the chipset technical sheet as that provides useful information on how the chipset actually works. I also downloaded the IET Labs DE5000 manual as that unit uses the same chipset so is basically the same but with a different front panel  IET rewrote the manual to improve it. I attach the chipset data sheet. The IET DE5000 manual is available here:

http://www.ietlabs.com/de5000-lcr-meter.html

The CAL button should really be on the front panel as is the case with the DE5000. It puts the chipset into the open/short AC calibration routine. This is a feature of the chipset to allow for the test fixture LCR characteristics and eliminate them from the readings. This is especially important for very accurate readings using long leads such as the tweezers. It is amazing that this was missed out of the manual !

The joy of this meter is that it is basically an excellent GENERIC chipset housed in a custom case....any LCR meter using the same chipset will behave in the same manner and should offer the same performance if built correctly. You can already find other LCR meters that are using this chip set....it is likely to become very popular and unlike custom chipsets there is likely to be more information becoming available regarding the behaviour of this most useful generic chipset. Manuals for other meters using this chipset should also be applicable to the Mastech unit in terms of test procedures etc.

Kind Regards

Aurora

[Lo_tse]

Hi, Aurora

Thank you very much for the information.  Much appreciated.  I was wondering whether I should write Mastech to enquire.  Well, I guess I have a lot of exploration to do , learning how to use this meter effectively.
 
When I opened the battery compartment, I was surprised to find that there was actually a compartment for a 9 v battery (not hooked up though), in addition to the space allocated for the 8 x 1.5 v AA cells.  I was curious why every LCR meter on the market (almost) use a single cell 9 v and the MS5308 needs  8 x 1.5V.  Granted, as far as I know (correct me if I am wrong), all the AC adapters for LCR meters are set at 12 V, e.g. the TH2822A. 

Thanks again and take care.

Regards,

Lo_tse

[Fraser]

Regarding the battery compartment.

I believe the case is actually the manufacturers generic assembly, and can be used for other products, like multimeter's, that may require a 9V battery.

It would be good to add the names of meters that are believed to use the same chipset in this thread as that may assist others with buying decisions and sources of better user manuals etc. The LCR meter specifications are the give away as if they mirror the Cyrustek chipset specs there is a very good chance that this is what lives inside the case.

I will start with the following:

Mastech MS5308
DER EE DE5000
APPA 703
V&A VA520
Extech LCR200 _ warning - no PC software or accessories !

Regards

Aurora

[Vredstein]

I didn't see a user replaceable fuse in any of the pics. Is this a relevant issue?

[free_electron]

One thing that is persistently missing from almost all LCR bridges is the capability to apply a bias voltage on the part while measuring. or to apply a bias current to an inductor while measuring

Especially with surface mounted parts this is becoming more and more a problem.
To give you an idea : a 1uf 0805 10 volt Y5V cap (according to the spec) with 6 volts applied has its capacitance decreased to 3 uf ... take the same part in 0603 package and you are left with 1.3 uf ... pump up the bias to the max (according to the spec) and you are lucky to have 100nF left over ... Heat it up or cool it down and your guess is as good as mine ...

X7R are much more stable. The problem is  : how do you tell an X7R from a Y5V ... especially if it already sits on a board and you suspect the assembly house used the wrong ones. You can only verify that by biassing the part.

The same goes with inductors. take a 1uh inductor for a buck or boost regulator , destined to run at 1 to 5 MHz switching range. This inductor is spec'd  for 3 ampere saturation current. But, depending on the core material used , one type may be 800uH at 2 ampere while another may be 0.5uH at the same 2 ampere ... If you got the latter : your switcher will become unstable, may hicckup and eventually destroy itself.

So, anyone know of machines that can do this ( at a decent price ? ) . I know wayne-kerr en Agilent have so called 'material analyzers' that start somehwere in the 50.000$ range... Throw in the biassing sources and it klimbs even further very fast ...

[onlooker]

If 1 to 5 MHz is to be the test frequency, it is way beyond the current topic of Mastech MS5308 LCR meter with or without taking into account of applying bias.  On the other hand, measuring LCR using any LCR meter with bias is just a easy "DIY" project, especially if the accuracy is not the concern (e.g. the sever non-linearity in the examples) right?

[free_electron]

If 1 to 5 MHz is to be the test frequency, it is way beyond the current topic of Mastech MS5308 LCR meter with or without taking into account of applying bias.  On the other hand, measuring LCR using any LCR meter with bias is just a easy "DIY" project, especially if the accuracy is not the concern (e.g. the sever non-linearity in the examples) right?

yes and no.. i'd like to be able to make some plots of how capacitors behave , so i'd like to be able to sweep the bias voltage for example... I don't know how this LCR meter is going to react if i start applying external voltage on the capacitor... most LCR's want to 'discharge' before measuring. Can't do that in my case. I want  to put 50 volts on that cap.. and measure its capacitance ...

I know the big bridges like the wayne-kerr's can do it. When i visit my parts suppliers ( TDK murata etc ) thay all have these big bridge. but hey are 50K$ and more (and they can alsoe do leakage, soakage, impulsa , sel sr and uch more .. i was just wondering if there is something a bit more 'hobby' that has biasing capability. ( let's say below 1K $ ... ) I habven't found one yet ( apart from my second hand HP LCR bridge 4263B that has a bias generator up to 1.5 volts.

[onlooker]

The discharge clause is meant to not apply (excessive) external voltage to the meter leads. If the DUT cap under bias is not too large, one can serial a "larger" and low ESR cap to the LCR to measure it. This is how I measure battery ESRs with my TH2822A (a 4 uF with esr=60m Ohms). On a side note, I think TH2822A is a better choice: On paper, it has better C and R accuracy/range, a little lesser H accuracy/range and it has 40000 counts (vs 20000) and better looking and not as bulky, though it does not do 100kHz. I think they are about same in price.

[T4P]

https://www.eevblog.com/forum/product-reviews-photos-and-discussion/tonghui-th2822-lcr-meter-review-teardown-and-possible-hacking/
Looks like it costs 230$ and it only does 10kHz and does not have a backlight .
Hmm . 
But really , do you need that extra counts in a LCR meter , i don't know .
If it was a normal DMM , ok .

[zoltm]

......  though it does not do 100kHz.

The TH2822C would do 100kHz.

[zoltm]

Curious if any more folks jump into this Mastech MS5308 bandwagon and have more first hand experience to share. In particular I would like to hear more on the quality of the test probes and consistency of the meter. 

I may make up another plug in unit with 4mm sockets for just such a requirement.

Make sure you do it with (4) 4mm sockets so you can maintain 4 lead kelvin style connection to your DUT if you want to maintain the accuracy you are enjoying.

PS. I have the DE5000  (I think the same chipset) and also impressed with its performance. Looking forward to Dave's review of it.

[LaurenceW]

Hello, I've also just landed me one of these Mastech meters, so here are my initial thoughts - no other LCR meters of worth in my possession to compare it against.

First impressions - Look at the SIZE of this thing! It's hee-uge. It must be FULL of clever electronics, then? At least, you could operate it while wearing oven gloves, and/or in hand-hand combat. Only why would you need to? Big display, (OK, that's always nice) big buttons, complex, fussy case moulding, with "pretend" rubber corner buffers. But it is all hard, black, plastic. A rather surplus fabric carry strap/handle (took that STRAIGHT off). Not a great fan of the design from the outside, me.  I think it might have been designed by a Lumberjack. Or gorilla, maybe. Look, it's not an IPad, that's what I'm saying.

With its accessories, the unit comes in a nice, padded bag. Which could also double up to keep your sandwiches AND a thermos flask in, or even for somewhere for the cat to crawl into and go to sleep. Did I mention - this thing is BIG

The large plastic tilt bail at the back of the meter is nice, and the case is so chunky and wide that it sits sturdily at an angle. The bail folds out from the battery pack - which houses no fewer than EIGHT AA batteries, thoughtfully, supplied. I have measured the current consumption (with the nice display backlight on) at around 25 mA, so the supplied set of alkaline AAs, albeit of unknown pedigree, can be expected to last  around 100 hours. That may not sound long, but the unit auto-powers off (and this cannot be disabled while on battery power) after about five minutes anyway. The  meter works down to a supply voltage of around 8.4V, so a little over 1V per cell - the point at which most alkalines have pretty well had it, anyway (so that's good).

Bizarrely, the rear moulding does also include room for a 9 V battery, although no wiring exists to support it.  Such a power source choice would have been a bit of a DISASTER for this meter, with an expected battery life then of maybe less than 25 hours. Why the two battery mouldings? I find it odd that this case was designed to be multi-purpose. I think it was a mould designer hedging his bets. Maybe he didn't know the current consumption of the (fairly new) chipset? It is rather inconceivable that any well designed electronics would need TWO such power sources.

The DUT (Device under Test, or "Object for Measuring" as the rather poor comedy manual refers to it) spring clips are rather tight, and have to be coaxed apart with a screwdriver before you can slot in the Device (or Object?). I guess I will mostly use the probes. I can see the hard plastic case getting scratched around the DUT sockets, after repeated poking with component wires.  Although the case is part designed to accommodate it, there are no options to plug in banana plug leads

Ok, we know what comes next. We don't just turn in on, we take it "apairt!"

I can do no better than the pictures already posted of the insides, so wont bother. There are a few things I am not so keen on, on opening my own instrument. I find that the pillars into which the self-tapping case screws are driven have mostly split. So that limits the number of times I will be taking the back of this baby!

FULL of electronics? Er, no! Just two main ICs, a handful of SMD discretes, a few manually soldered bits and flying wires (not the best quality) and that's it. This looks pretty close to the other designs that use this newish chip set, so they can be expected to perform similarly. Loads of SPACE - the designers could have made the PCB half the size and still had room for a large display and reasonable keyboard.

Why a separate daughter-board (needs own mounting screws and flying wires) just for the on-off button? That could so easily have been included on the main PCB, if the switch had been better sited. And another daughter board for the external power socket - I am sure they could have mounted that on the main PCB.

The "Cal" switch (barely mentioned in the manual) is the weirdest thing! It seems to be a complex device, when surely a simple tactile "click" switch would have done the job. With it's own mini-PCB, I had it down for some sort of sensor at first, but no.

There is no internal shielding, so the meter did not take kindly to the "stick a GSM phone on full output right up against it" test, but it recovered well enough, when the phone is removed.

Given that the meter is trying to measure potentially small values of resistance, capacitance and inductance, the designers could not afford to have lots of multimeter-style protection electronics getting in the way between the DUT and the clever measurement electronics. So input protection of this class of meter is very low. Yes, it does warn you of this on the front of the meter. But anyway, as others have pointed out, what damn fool would be stupid enough to  expose this instrument, via its test probes, to a killer voltage in a live circuit? Well, speaking as a fully qualified damn fool myself, its very easy to do! So THINK before you plug this meter into anything. It wont survive multimeter-style abuse.

As mentioned, the backlit display is a nice size, but a bit crowded. It includes a bar-graph trend meter - great for showing voltage or current trends  and general VARYING quantities on an appropriate meter - but on an LCR component meter? Daft.

All in all, a bit clunky, especially when compared to your typical, even larger, multimeter.

The meter is supplied with an infra-red connector - important for electrical isolation - to RS232 connector (remember them? No? Ask your dad). I've not tried this yet, but the information flow is only ONE WAY (LCR to PC) so your PC can only record values, but not control the LCR Meter. The software looks basic.

OK - does it work? Well, yes it does, and within spec, based on the small number of reference resistors, capacitors and inductors I have thrown at it. It produces more information about the DUT than the supplied poor manual will reveal. Instead, you should download and read the excellent manual for the IET DE-5000 device, which is electronically identical, I suggest (they move keys and stuff around on the LCD, but it's all the same segments, just in different places).

Maybe you are asking yourself: "Do I need an LCR meter? My multimeter measures C and R well enough".  Well, if you only need to know the resistance of resistors and the capacitance of capacitors, then probably not. But if your circuit designs need you to dig further into the ESR (equivalent series resistance) of a capacitor or the Q of an inductor, then that is where an LCR meter like this will leave your multimeter for dust.

One surprise is the widely differing capacitance readings given for the same device at different frequencies. Which is correct? I need to read up on that!

I expect a number of manufacturers will release very similar products on this same chipset, and I can see nothing to hold the price up for long. Expect $99 LCR meters looking remarkably similar to this one, soon.

The Mastech MS5308 doesn't have the polish (or price!) of a Genrad/IET DE-5000, but yet  it does have the performance. I'd say for home, lab or  non-production use, it would be fine. Yes, glad I bought it but, as I say, it's no Genrad.

[amspire]

One surprise is the widely differing capacitance readings given for the same device at different frequencies. Which is correct? I need to read up on that!

You didn't say what "widely" means in numbers, but capacitance does vary with frequency - even for secondary standard quality reference capacitors.

Remember that when you measure capacitance you are measuring a net effect, and inside the capacitor there can be both capacitance and inductance along with resistive and dielectric losses. Also the dielectric properties can change with frequency and voltage.

If you try different types of capacitors, you will probably find something like a 1nF SMD ceramic capacitor is far more constant then a wound polyester or electrolytic capacitor.

Also you have to look at the reality of the test frequency. A 1uF cap at 100KHz is only 1.6 ohms impedance, so lead resistance can effect the result. A 100pF cap at 100Hz is 16 MOhms so if the meter can read it at 100Hz , it probably has a low accuracy.

Richard.

[The Electrician]

Using an impedance analyzer to plot the variation of component parameters with frequency can provide insight into the different measured values of capacitance at different frequencies.

I've attached some images showing the series equivalent capacitance and series equivalent resistance (ESR) for various capacitors with the frequency swept from 1 kHz to 5 MHz.

The green curve is the capacitance and the yellow curve is the ESR.  The first image shows the result for a Wima 4.7 uF polypropylene capacitor.  This is a very low loss capacitor.  The capacitance is 4.58 uF at 1 kHz (marker A is set to 1 kHz), but as the frequency increases the measured capacitance slowly increases as we approach the self resonance frequency.  At 100 kHz, the measured capacitance is 5.38 uF (marker B is set to 100 kHz).  We see the series resonance occurring at about 250 kHz.  The measured capacitance at frequencies higher than 250 kHz would be negative because the capacitor looks like an inductor at those frequencies.

The yellow curve shows that the ESR is about 1.2 milliohms at 20 kHz; at 100 kHz, the ESR is 2.708  milliohms.  This is a very good capacitor.

The second image shows the result for a Sanyo ultra low ESR capacitor of the sort used in computer mother boards.  The rated capacitance is 1800 uF.  It measures 1660 uF at 1 kHz with an ESR at 100 kHz of a little more than 9 milliohms.  But look what happens when we try to measure the capacitance at 100 kHz.  The series resonance occurs at a little over 50 kHz and the measured capacitance at 100 kHz is -974.7 uF.  This is because the capacitor is looking like an inductor at frequencies greater than the series resonance frequency.  We also notice that as the frequency increases from 1 kHz, the capacitance looks like it might be decreasing just a little.

The third image shows the result for a 33 uF 50 volt ordinary electrolytic, not ultra low ESR.  Notice that the capacitance decreases as it approaches series resonance and finally begins to rise just before series resonance as the other capacitors did.  What causes this decrease in capacitance?

The capacitor manufacturers, such as Cornell Dubilier, explain in application notes that this is the result of etching the aluminum foil that forms the electrodes in the capacitor.  The etching process causes the surface of the foil to become very irregular and covered with pores.  This increases the surface area, which in turn increases the capacitance for a given physical size of capacitor.  But a side effect of the many small pores is that although the liquid electrolyte does penetrate the pores, the speed of movement of ions in the pores is slow enough that at the higher frequencies the apparent capacitance is reduced by this slowdown of ion movement in the pores.

The capacitance measured at 100 kHz may be quite different than at lower frequencies because of the possibility that the series resonance frequency may be just a little above 100 kHz, or even below 100 kHz in which case the measured capacitance may show up as a negative number.

[The Electrician]

For some electrolytic capacitors, the etching process has been carried to an extreme to get large capacitance in a small package.  The first attached image shows the result for a very small 47 uF, 16 volt capacitor.  The variation in capacitance as series resonance is approached is extreme.  Imagine if a designer had specified this capacitor for use as a filter in a switcher running at 100 kHz or higher.  The measured capacitance at 100 kHz is only 4.6 uF rather than the rated 47 uF!  At 500 kHz, it's only 1 uF!  The ESR is none to great either.  But, at 60 Hz the capacitance is what it should be.

Another thing to watch out for when measuring is the length of the capacitor leads.  The second image shows 4 superimposed sweeps with various lead lengths.  One is with the full length leads for a 15 uF capacitor.  The other three are showing what happens when I pushed the capacitor leads into the measuring contacts various amounts (the resonance frequency changes), with the last (highest resonance frequency) when the leads are as short as possible.  The measurement at 100 kHz for this capacitor doesn't change much for different lead lengths, but if a larger capacitor is measured whose resonance is just above 100 kHz, the measured values at 100 kHz would vary much more with lead length.

The third image shows a capacitor whose ESR varies nearly an order of magnitude from 1 kHz to 5 MHz.  The heating due to ripple current in this capacitor would be quite different for 1 kHz ripple than for 100 kHz ripple current.  The ESR measured by the low cost ESR meters found on the web might be inaccurate by quite a bit for a capacitor like this whose ESR varies a lot with frequency.

[LaurenceW]

Electrician and AMspire, those are interesting discussions, and it is useful to see the behaviour of a component across a swept range of frequencies, rather than spot values. I guess I knew that the a component's apparent values must shift with frequency, but I hadn't thought about the degree. Heck, it amazes me that half of this stuff works at anything faster than DC!

[Fraser]

I agree with the comments made in the review by LaurenceW but think it worth making some additional comment.

The case is LARGE but that is clear from the units specification so should not be a surprise. Unlike the Unit-T bench multimeters that are a bit like a sandwhich box with a single PCB behind the front panel, I do feel that the MS5308 is appropriate as a bench meter. It is portable if needed but it makes a very clear and stable bench meter. I have the Wayne Kerr 4210 and that is a true monster in comparison, as are the likes of Racal and other bench LCR meters. Mastech already sell several handheld LCR meters and this unit apppears to be a bit of a 'statement piece' with the size and unusual 'Tektronix like' case supposed to infer professional quality  ?

As the unit uses a known generic chipset and the PCB is, IMHO, of acceptable quality to maintain the chipsets specified accuracy, it is really a case of buying the Cyrustek based LCR meter that meets the size and cost specification of the user. I agree that prices may drop but LCR meters are not as common as multimeters so that may always have an effect on price (though UNI-T seem to have made this a myth with their cheap LCR meters).

When comparing the MS5308 to other LCR meters, it is well worth considering what is supplied with the meter. In the 'large' carry bag you get the MS5308, batteries, interface lead, software, PSU, Tweezer adapter, Kelvin Clips adapter and the bag itself    Some other competitors appear to charge extra for the accessories which can up the price considerably. The MS5308 hits the ground running and is a complete package upon arrival.

In my specific case, the size is a benefit and I am not unhappy with the design or the plastics used. This is not a flimsy unit and I am thankful that it has not been covered in that awful thin rubberised layer found on some equipment.....such rubberisation can go sticky with time and use. A rubber boot around the case would have been great but is not essential in my scenario. It is not a significantly inferior case to my Tektronix THS-720 DSO which is also of hard plastic but durable.

With regard to the batteries required. LCR meters are power hungry and I am pleased that Mastech give the option of a PSU or AA batteries. As Dave has stated, AA battery capacity is far preferable to that of small PP3 batteries. The 9V battery slot is interesting. I seem to recall that another LCR meter used AA plus PP3 batteries for some reason (not known by me) Mastech have gone the correct route and taken all required supplies from one battery pack.

To summarise......... Yes its large, Yes its Plastic, Yes it takes a lot of batteries......BUT it does what it says on the tin, Yes it comes with lots of accessories and Yes it appears robust. It is like Marmite, you either love the design or hate it 

The price was certainly good value for money as well, and it came from a UK warehouse in double quick time 

I would think any half decent LCR meter using the Cyrustek chipset will be good unless the manufacturer messes up the PCB design. My advice is.....Pick the design and price that most suits your needs. THEN download the DE5000 manual as has been stated 

Aurora

[amspire]

With regard to the batteries required. LCR meters are power hungry and I am pleased that Mastech give the option of a PSU or AA batteries. As Dave has stated, AA battery capacity is far preferable to that of small PP3 batteries. The 9V battery slot is interesting. I seem to recall that another LCR meter used AA plus PP3 batteries for some reason (not known by me) Mastech have gone the correct route and taken all required supplies from one battery pack.

My guess is they had to leave the option open to go back to a 9V battery. Either they  had a switching converter, and they were not sure if it could cause interference, of they were not sure if they could get the performance required without extra voltage to part of the circuit. I think this must happen a bit, as I have seen multimeter cases with "9V" molded into the plastic as the operating voltage, but inside they run of two AAA batteries.

Richard.

[amspire]

Electrician and AMspire, those are interesting discussions, and it is useful to see the behaviour of a component across a swept range of frequencies, rather than spot values. I guess I knew that the a component's apparent values must shift with frequency, but I hadn't thought about the degree. Heck, it amazes me that half of this stuff works at anything faster than DC!

The Electrician is choosing the type of capacitors that will have variations, and they are not the capacitors you would pick if you needed accuracy at 10MHz.

The performance of something like a 100pF NPO SMD capacitor is good over a much wider range.

If you think capacitors are bad, you better not start testing inductors.

If it makes you feel any better about capacitance, until the Quantum Hall Effect resistance standards came along, the resistance standard were calibrated using a special quadrature bridge from a primary standard capacitor - a 0.5pF calculable capacitor. Last I heard, someone had reached 18 digits of resolution in measuring it. The measurement frequency is usually 1KHz, the dielectric is a vacuum, and the test voltage is probably in the hundreds of volts at least - perhaps thousands of volts.

The best capacitors we can make are many orders of magnitude more accurate and stable then any non-Quantum Hall effect resistor, but you would not know it from the parts we have to use everyday.

Richard.

[The Electrician]

I chose the capacitors to be responsive to the question:

One surprise is the widely differing capacitance readings given for the same device at different frequencies. Which is correct? I need to read up on that!

Even the lowest cost LCR meters usually measure at 100 Hz, 120 Hz and 1 kHz, and you won't usually see much difference in the readings at those frequencies, but the meters that also measure at 100 kHz may see differences even for perfectly good capacitors.  My purpose was to explain why non-defective capacitors can give different readings at different frequencies.

Ths slow-ion-movement-in-etched-pores effect is, AFAIK, limited to electrolytics.  The series resonance effect is going to be noticed at 100 kHz only with large valued capacitors.  As you say, small valued capacitors such as 100 pF caps, won't show these effects at 100 kHz.

These effects take place even if the capacitor is not defective, and the user of a 100 kHz capable LCR meter should keep them in mind.  The different readings don't necessarily mean that the capacitor is bad.

I hope LaurenceW hasn't gotten the impression that capacitors are bad; they just have limitations one should be aware of.

As my plots show, not all electrolytic capacitors exhibit the slow ion effect; an LCR meter can help detect which ones do.

Here are plots of a couple of capacitors from my collection.  They are identical older Mallory capacitors with an epoxy seal rather than the currently more common rubber seal.  They are rated 50 uF at 50 volts.  There are no signs of swelling or leakage around the epoxy seal, yet something is wrong with one of them.  The good one, Mallory1, has a capacitance of 66.8 uF at 1 kHz and a respectable ESR of .308 ohms.  The bad one, Mallory2, has a capacitance of 8 uF at 1 kHz and an ESR of 82 ohms!

The images show the sweeps of the caps individually and superimposed.

[The Electrician]

There has been at least one thread on the forum that asks whether it's worth getting an LCR meter with 100 kHz capability.  In the past this has cost a substantial increment in price, but recently the price increment isn't so large.

Here's a nifty thing you can do with a meter having a 100 kHz measurement capability.

I've attached an image showing a sweep of the impedance at one end of a 100 foot roll of telephone twisted pair cable.  This is the old stuff, not modern Cat5 cable.  The image show two sweeps superimposed; one with the other end of the cable open circuited and one with the other end of the cable short circuited.  The impedance where the two curves cross is the characteristic impedance of the cable.  Marker B is set at one of those crossings; the frequency is 2.5255 MHz and the impedance is 112.686.  This kind of cable is usually said to have a characteristic impedance of about 100 ohms; the measurement confirms this.

An LCR meter that can measure Z and phase angle (theta) can be used to determine the characteristic impedance of a cable.  A measurement frequency of greater than 100 kHz would be better, but 100 kHz can do a fairly good job.  You will need a substantial length of the cable, 100 feet or more.

Connect the meter to one end of the cable with the other end open circuited.  Measure the impedance at 100 kHz; I got 1166<-89.6 (this is 1166 ohms at a phase angle of -89.6 degrees).  Now short circuit the other end of the cable and measure the impedance again; I got 13.42<64.87.

Multiply the ohms readings: 1166 * 13.42 = 15647.72.  Take the square root of this: SQRT(15647.72) = 125.09; this is the characteristic impedance.  This compares favorably with the value of 112.686 obtained from the sweep in the image.  For a check, add the two phase angles: -89.6 + 64.87 = -24.73; divide by 2 and get -12.365.  This is the phase angle of the impedance; ideally it should be zero, if it's small, the value for the impedance is likely to be close to the correct value.

If you try this same procedure at 10 kHz, you will get a not so good result, so this is why 100 kHz capability is a good thing.

[zoltm]

Hi Electrician,

You description below gets me curious, if the 100K capable LCR meter could indeed help to measure the effective impedance on an audio loudspeaker?

Thanks.
 

There has been at least one thread on the forum that asks whether it's worth getting an LCR meter with 100 kHz capability.  In the past this has cost a substantial increment in price, but recently the price increment isn't so large.

Here's a nifty thing you can do with a meter having a 100 kHz measurement capability.

I've attached an image showing a sweep of the impedance at one end of a 100 foot roll of telephone twisted pair cable.  This is the old stuff, not modern Cat5 cable.  The image show two sweeps superimposed; one with the other end of the cable open circuited and one with the other end of the cable short circuited.  The impedance where the two curves cross is the characteristic impedance of the cable.  Marker B is set at one of those crossings; the frequency is 2.5255 MHz and the impedance is 112.686.  This kind of cable is usually said to have a characteristic impedance of about 100 ohms; the measurement confirms this.

An LCR meter that can measure Z and phase angle (theta) can be used to determine the characteristic impedance of a cable.  A measurement frequency of greater than 100 kHz would be better, but 100 kHz can do a fairly good job.  You will need a substantial length of the cable, 100 feet or more.

Connect the meter to one end of the cable with the other end open circuited.  Measure the impedance at 100 kHz; I got 1166<-89.6 (this is 1166 ohms at a phase angle of -89.6 degrees).  Now short circuit the other end of the cable and measure the impedance again; I got 13.42<64.87.

Multiply the ohms readings: 1166 * 13.42 = 15647.72.  Take the square root of this: SQRT(15647.72) = 125.09; this is the characteristic impedance.  This compares favorably with the value of 112.686 obtained from the sweep in the image.  For a check, add the two phase angles: -89.6 + 64.87 = -24.73; divide by 2 and get -12.365.  This is the phase angle of the impedance; ideally it should be zero, if it's small, the value for the impedance is likely to be close to the correct value.

If you try this same procedure at 10 kHz, you will get a not so good result, so this is why 100 kHz capability is a good thing.

[Lo_tse]

I agree with the comments made in the review by LaurenceW but think it worth making some additional comment.

The case is LARGE but that is clear from the units specification so should not be a surprise. Unlike the Unit-T bench multimeters that are a bit like a sandwhich box with a single PCB behind the front panel, I do feel that the MS5308 is appropriate as a bench meter. It is portable if needed but it makes a very clear and stable bench meter. I have the Wayne Kerr 4210 and that is a true monster in comparison, as are the likes of Racal and other bench LCR meters. Mastech already sell several handheld LCR meters and this unit apppears to be a bit of a 'statement piece' with the size and unusual 'Tektronix like' case supposed to infer professional quality  ?

As the unit uses a known generic chipset and the PCB is, IMHO, of acceptable quality to maintain the chipsets specified accuracy, it is really a case of buying the Cyrustek based LCR meter that meets the size and cost specification of the user. I agree that prices may drop but LCR meters are not as common as multimeters so that may always have an effect on price (though UNI-T seem to have made this a myth with their cheap LCR meters).

When comparing the MS5308 to other LCR meters, it is well worth considering what is supplied with the meter. In the 'large' carry bag you get the MS5308, batteries, interface lead, software, PSU, Tweezer adapter, Kelvin Clips adapter and the bag itself    Some other competitors appear to charge extra for the accessories which can up the price considerably. The MS5308 hits the ground running and is a complete package upon arrival.

In my specific case, the size is a benefit and I am not unhappy with the design or the plastics used. This is not a flimsy unit and I am thankful that it has not been covered in that awful thin rubberised layer found on some equipment.....such rubberisation can go sticky with time and use. A rubber boot around the case would have been great but is not essential in my scenario. It is not a significantly inferior case to my Tektronix THS-720 DSO which is also of hard plastic but durable.

With regard to the batteries required. LCR meters are power hungry and I am pleased that Mastech give the option of a PSU or AA batteries. As Dave has stated, AA battery capacity is far preferable to that of small PP3 batteries. The 9V battery slot is interesting. I seem to recall that another LCR meter used AA plus PP3 batteries for some reason (not known by me) Mastech have gone the correct route and taken all required supplies from one battery pack.

To summarise......... Yes its large, Yes its Plastic, Yes it takes a lot of batteries......BUT it does what it says on the tin, Yes it comes with lots of accessories and Yes it appears robust. It is like Marmite, you either love the design or hate it 

The price was certainly good value for money as well, and it came from a UK warehouse in double quick time 

I would think any half decent LCR meter using the Cyrustek chipset will be good unless the manufacturer messes up the PCB design. My advice is.....Pick the design and price that most suits your needs. THEN download the DE5000 manual as has been stated 

Aurora

I totally agree with Aurora. I bought one after reading his earlier review and after quite a bit of research on the internet.  Particularly some of the comments on the Chinese DIY forum Crystalsradio (in Chinese).  It was on Crystalsradio that someone commented on the "spacious interior" of the meter.  One of the poster did a quick comparison of the Mastech meter with a certain model of Agilent bench LCR meter and was quite happy about the accuracy. 

I am not a big fan of the plastic shell but it seems sturdy enoug.  The meter comes with all the accessaries that I wanted and more (the data cable) and I only paid 150 US$ for it (plus 55$ for shipping).  The only unknown at this point is the longevity of the meter and only time will tell.  For DIY use, I think this meter is way more than adequate. 

Lastly, I would like to thank Aurora again for informing me about the manual of the IET 5000 - night and day as compare to the one that comes with the meter.  Mastech should be ashame. 

Regards,

Lo_tse

[The Electrician]

Hi Electrician,

You description below gets me curious, if the 100K capable LCR meter could indeed help to measure the effective impedance on an audio loudspeaker?

Thanks.
 

There has been at least one thread on the forum that asks whether it's worth getting an LCR meter with 100 kHz capability.  In the past this has cost a substantial increment in price, but recently the price increment isn't so large.

Here's a nifty thing you can do with a meter having a 100 kHz measurement capability.

I've attached an image showing a sweep of the impedance at one end of a 100 foot roll of telephone twisted pair cable.  This is the old stuff, not modern Cat5 cable.  The image show two sweeps superimposed; one with the other end of the cable open circuited and one with the other end of the cable short circuited.  The impedance where the two curves cross is the characteristic impedance of the cable.  Marker B is set at one of those crossings; the frequency is 2.5255 MHz and the impedance is 112.686.  This kind of cable is usually said to have a characteristic impedance of about 100 ohms; the measurement confirms this.

An LCR meter that can measure Z and phase angle (theta) can be used to determine the characteristic impedance of a cable.  A measurement frequency of greater than 100 kHz would be better, but 100 kHz can do a fairly good job.  You will need a substantial length of the cable, 100 feet or more.

Connect the meter to one end of the cable with the other end open circuited.  Measure the impedance at 100 kHz; I got 1166<-89.6 (this is 1166 ohms at a phase angle of -89.6 degrees).  Now short circuit the other end of the cable and measure the impedance again; I got 13.42<64.87.

Multiply the ohms readings: 1166 * 13.42 = 15647.72.  Take the square root of this: SQRT(15647.72) = 125.09; this is the characteristic impedance.  This compares favorably with the value of 112.686 obtained from the sweep in the image.  For a check, add the two phase angles: -89.6 + 64.87 = -24.73; divide by 2 and get -12.365.  This is the phase angle of the impedance; ideally it should be zero, if it's small, the value for the impedance is likely to be close to the correct value.

If you try this same procedure at 10 kHz, you will get a not so good result, so this is why 100 kHz capability is a good thing.

Any LCR (or LCZ) meter can be used to measure a speaker impedance; you only have to connect the speaker to the meter.  The impedance is, of course, only measured at one of the test frequencies used by the meter.

It appears to me that the MS5308 doesn't have a z/theta mode.  For a meter that doesn't have such a mode, you will have to derive the impedance from a measurement of Ls and Q or Cs and D.

[LaurenceW]

Well no, I don't necessarily think capacitors are bad. Despots, Hyper-inflation, droughts, anything by Boney-M; they're BAD. Capacitors are just capacitors. (mainly). Clearly, not all caps are created equal.

It is interesting and educational to me to see how different capacitors perform and measure at different frequencies.  I learn that Polystyrene caps are pretty damn good, and give consistent high quality readings. I learn that electrolyics basic values don't vary  as much as the often quoted -20/+80% tolerances would lead you to believe.

 I wasn't expecting to see even quite small electrolytics drop off in indicated value at higher frequencies, so rapidly. I guess that's other parameters in the component coming into play (and maybe explains why you'll often see a small ceramic cap straight across a larger electrolytic one)

I am not complaining about more batteries - (8 AA's) over a smaller 9V pack. The larger solution will last MUCH longer and be cheaper too.

The size is of the MS5308 is what the size is, and yes, it's probably even written down in the spec, somewhere. Did I read that? NAH! But there is no doubt that this instrument is larger than it needs to be.  It packs a lot of fresh air. "Pocket" it is not!

My experience to date of the PC software is that it is C R A P. Actually, I cannot get it to work, but even if it ever does, I don't think I've got a use for it. It looks to be poorly written, and is VERY basic. Data doesn't even fit in the (fixed size) windows. The software doesn't even appear to capture all of the parameters that the meter is capable of measuring. But this is not why I bought the instrument.

Still happy on balance with my purchase, though.