LCR meter questions and maybe recommendation.  - Page 1
Forum section: electronics / testgear

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: June 02, 2024, 08:49:46 pm
content: Ive stepped away from hobby electronics for a while just busy work(electrician) and being a single parent, but have found myself wanting to get back in to some projects lately. I have most test equipment I need, the only thing I am missing besides a decent spectrum analyzer is an LCR meter. I was harvesting some parts the other day and realized I had no way to easily measure the IF cans I pulled. In the past when measuring inductance I have relied on one of three techniques.#1 A common ebay TC-1 transistor/component tester#2 Siglent SDS1104x scope controlling Siglent SDG1032x AWG@(hacked to 60mhz), that can plot I/V/phase etc etc#3 A nanoVNA2The TC-1 is great for a quick ballpark number as long as the tester recognizes it as an inductor and not a wire wound resistor, which is a huge problem with most inductors for RF filtering and even switching power supply design, because there inductance is to small for the TC-1 to measure. Using the scope/awg gives pretty decent results up to 60mhz but is kind of a PITA to set up. NanoVNA is also a PITA to use to measure components because everything is has to be 50ohm and you have to build some kind of a test fixture.After watching some reviews of handheld LCR meters I'm left with a few questions. First of all do they commonly give you the Z value at the meters selected frequency. I see that they mostly give you Q,D and X but the only one I have seen giving Z is the Peak Atlas LCR45.Also im having a hard time understanding how useful an LCR meter is for measuring inductors you plan to use outside the frequency range outside the meter. For example if I use a calculator to wind an air core coil for a VHF filter or something can I use the LCR meter to verify the value of the coil? What about coils using iron or ferrite cores? Does the frequency a coil is driven at effect the inductance of the coil? If so that would make the meter useless for any coil being used at a frequency higher than 100khz or whatever the LCR meters top frequency is? Even a switching power supply runs at higher a frequency than the pretty standard 100khz of these meters.

author: tautech
author_rank: Super Contributor
timestamp: June 02, 2024, 09:13:33 pm
content: 2 decades ago I was also looking at LCR meters and also getting into SMD.I selected smart tweezers as a universal solution for both which quickly became an indispensable tool.Much has changed and now many bench LCR devices exist yet SMD tweezers remain my tool of choice.I highly recommend you look hard at ST42 and its record of development here:https://www.eevblog.com/forum/testgear/design-a-new-precision-lcr-tweezers/For more detailed info, Shannon's website might be useful also:https://shannontweezers.github.io/docs/introduction/

author: shabaz
author_rank: Frequent Contributor
timestamp: June 02, 2024, 09:24:11 pm
content: From what you mention, probably a VNA is way more useful. Agree it's not as convenient as a couple of of alligator clips to perform a measurement, but you'll get way more satisfactory results since you're measuring at the frequency you'll actually be using it.I have a couple of LCR meters, plus other tools that perform similar-ish operations, but I probably use the VNA more often, especially if as you say, the frequency of operation is going to be much higher.For toroid and air core, calculations can be fairly accurate, so unless even more accuracy is needed, I might not measure and just tune in the circuit.Sometimes I might use ready-made inductors, e.g. CoilCraft kits can be handy, they come in tolerances like 2.5%. I have no issue constructing DIY inductors, and keep various ferrites and iron cores handy. For typical HF/VHF work, software like Coil64 is as accurate as is practically possible without electromagnetic simulation tools I think - I've had a good experience with that software.

author: Martin72
author_rank: Super Contributor
timestamp: June 02, 2024, 09:30:13 pm
content: Quote from: tautech on June 02, 2024, 09:13:33 pmFor the applications he has outlined, the tweezers can only be considered as a supplement.Or I would only get them as a supplement, not for everything, the maximum frequency alone is too low for that.

author: nctnico
author_rank: Super Contributor
timestamp: June 02, 2024, 09:56:53 pm
content: You need multiple instruments. An LCR meter is OK for determining inductance. For an inductor with a core, it is nice to be able to have current flowing through it so you can measure the saturation point. A VNA is a good instrument to measure the self resonance frequency of an inductor.

author: Martin72
author_rank: Super Contributor
timestamp: June 02, 2024, 10:14:46 pm
content: QuoteYes, we have built a testing device for this, which is not available on the market in this form.Or only one and it has to be connected to a PC, ours works independently with the option of connecting a scope, precisely because of the saturation sighting.The principle behind it is known and exists in construction proposals on the net, but ours can generate currents of up to 200A, so you can stress coils a bit.A normal LCR cannot keep up with this, and depending on the core material, completely incorrect values are even displayed.

author: tautech
author_rank: Super Contributor
timestamp: June 02, 2024, 10:30:07 pm
content: Quote from: Martin72 on June 02, 2024, 09:30:13 pmShall we just see your impression of ST42 when you have more experience with them after they arrive.You did weaken to ordering a pair didn't you ?

author: Martin72
author_rank: Super Contributor
timestamp: June 02, 2024, 11:07:19 pm
content: My dear Rob,I have no doubt that the ST42 will be a good devicewithin its capabilities.But it can't perform miracles and make other topologies superfluous, with all due respect.Measuring and calibrating coils and transformers is an almost daily task for us.We use different measuring methods and different devices for this because no device can do everything.So I have some experience with this, so I can already say that it won't be any different with an ST42.It is limited in its measuring voltage, it is even more limited in its measuring current and finally in its measuring frequency.In addition, the mechanical design alone means that it can only measure SMD components.You can buy the ST42 in addition, as a stand-alone measuring device it is too limited in principle.Believe me.(That doesn't change the fact that it's already on my list)

author: tautech
author_rank: Super Contributor
timestamp: June 02, 2024, 11:36:49 pm
content: Yes of course Martin but your measurements needs do not equate to what other might require.What isgood enoughis very different for us all.

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: June 03, 2024, 02:15:32 am
content: Thanks for the info, ill probably just pick up an LCR meter to use in conjunction with my other devices. Probably the east tech desk meter or a peak lcr meter. I dont have much of a need for tweezers, if im using smd i trust the package.. this is more for verifying home made coils.

author: tautech
author_rank: Super Contributor
timestamp: June 03, 2024, 02:47:32 am
content: Quote from: rwgast_lowlevellogicdesin on June 03, 2024, 02:15:32 amWhich was my initial need too.Just because they are SMD tweezers don't by any means think that's all they can do.

author: shabaz
author_rank: Frequent Contributor
timestamp: June 03, 2024, 03:25:57 am
content: I don't know if the online specs for the ST42 are correct or not, but it's a bit concerning. The minimum inductance is 0.5uH, which is going to be troublesome if checking typical coils for (say) VHF purposes. I often use far smaller inductances, hand-wound.Appreciate not everyone will need small inductances, but OP has a callsign in their signature, so there's a chance small inductances might be needed for commonly-used bands, so worth raising as a thing to check, before ruling any LCR meter in or out.

author: KungFuJosh
author_rank: Super Contributor
timestamp: June 03, 2024, 03:34:30 am
content: Quote from: shabaz on June 03, 2024, 03:25:57 amMeasuring in the nH range is more difficult, and even more expensive LCR meters have trouble doing so. I think 500nH is fairly impressive for such an inexpensive tweezers.The attached chart is for a high quality bench LCR series that costs between 10 to 20 times more than the ST42, and the 100nH to 10nH ranges are clearly not ideal, even at that price range.

author: shabaz
author_rank: Frequent Contributor
timestamp: June 03, 2024, 03:45:59 am
content: Agree, it seems a useful tool in any case. I just meant to highlight it in case the OP intends to measure smaller inductances.

author: Martin72
author_rank: Super Contributor
timestamp: June 03, 2024, 05:53:31 am
content: Quote from: tautech on June 02, 2024, 11:36:49 pmIt has little to do with it, I just wanted to point out that you can't cover everything with one device and if the OP only has standard tasks (he doesn't), then he can use almost any meter.

author: HalFoster
author_rank: Frequent Contributor
timestamp: June 03, 2024, 12:15:06 pm
content: For all around usefulness and accuracy at a affordable price the best option, IMO, is a DE-5000 with added (easily DIY) kelvin clips. I have three different lab grade .05% accurate LCR meters, both testing up to 1MHz with programmable offsets, but the one that gets used constantly is my DE-5000 - it's easy to use and "just works." As with much test gear the cost goes up pretty much exponentially when you start requiring higher end functionality - in ESR meters that pretty much equates to maximum test frequency. Personally if I was needing to characterize inductors at higher frequencies I would get a DE-5000 and spend the money saved on a good VNA - it would do the job and add a tremendous amount of additional options to your bench. If you haven't, check out what the little Nano VNA is capable of - pretty amazing, IMO.Hal

author: beatman
author_rank: Regular Contributor
timestamp: June 03, 2024, 12:47:04 pm
content: I use the extech lcr200 and keysight u1732c .Extech is more speedy than keysight.Accuracy between units variance from 0.5 to 2 % depence what i measure.Keysight have big hidden menu to change parameters and preferences. I like booth units.

author: mawyatt
author_rank: Super Contributor
timestamp: June 03, 2024, 01:57:00 pm
content: To use an LCR meter over a broad range of components and values requires some understanding of the measurement principles if one expects reasonable accuracy.The low cost all-in-one component devices utilize a pulse technique whereas the more expensive lab type bench LCR meters utilize sine-wave measurement techniques (can explain if interested), the later usually better for accurate measurements, altho the all-in-one do a respectable job with most components.Small inductors represent a low impedance at lower frequencies which limits the measurement capabilities, the LCR meters allow the frequency to be set and generally the higher the better for small inductors as the impedance is directly proportional to frequency (well below the self resonate frequency). Since these meters actually measure DUT voltage and current, a small inductor (low impedance) produces a low voltage and high current, thus difficult to measure accurately. The reverse is true for small capacitors (high impedance), low DUT current and high DUT voltage.Many of the quality LCR meters have a table/graph which shows the component ranges, frequency and the accuracy "Sweet Spot" which should be consulted if one desires the most accurate results.The mentioned DE-5000 handheld LCR meter is based upon a specialized chip-set which performs almost all the functions and measurements, keeping the cost reasonable. We have one and it has demonstrated good performance against our Lab Grade Tonghui TH2830 and Hioki IM3536 LCR meters.We have and utilize all 3 meters, the IM3536 goes to 8MHz and why we have this, however it's expensive (~$4600), the TH2830 is 100KHz (~$1000) and high quality good value Lab Bench LCR meter, and the DE-5000 (~$200) for the general measurements.Another thing one might consider is having a set of stable "Reference Components" to check. We have various resistors and capacitors, altho no inductors, we can compare. Precision stable resistors are abundant, however capacitors are more difficult to find. C0G/NP0 ceramic capacitors are good for low values, Mica & Polystyrene good more mid values, and Polypropylene for higher values.Best,

author: KungFuJosh
author_rank: Super Contributor
timestamp: June 03, 2024, 03:01:52 pm
content: While the Tonghui LCR is awesome, their support sucks. Better to get the rebranded SourceTronic version if you can. 😉

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: June 03, 2024, 03:08:43 pm
content: One question no one answered was is it common for these meters to give a Z reading on the component at the meters selected frequency. The peak lcr meter does do this, i watched kerry wongs review of a couple lcr meters and the all seemed to give values for D,X,Q and ESR but he never showed Z so im not sure if any meter besides peak does this.At higher frequency i usually work at 200mhz and under and L band(~1-2ghz). I do use a nanoVNA2 for that stuff. Ive been looking in to buying a siglent spectrum analyzer with VNA option, although im not sure how much better that would be for VNA use.

author: KungFuJosh
author_rank: Super Contributor
timestamp: June 03, 2024, 03:18:00 pm
content: Quote from: rwgast_lowlevellogicdesin on June 03, 2024, 03:08:43 pmPlenty of LCR meters do include Z. The Shannon ST42 tweezers do. The TongHui/SourceTronic 283X series do. At least some of the Instek LCRs do too. You can search for LCRZ meters or Impedance Meters too.

author: mawyatt
author_rank: Super Contributor
timestamp: June 03, 2024, 04:02:45 pm
content: @OPThe LCR meters don't measure L, C nor R directly, they measure the complex voltage across DUT and complex current thru DUT, then compute the desired display parameter from such.Almost all Bench LCRs meters show Z, some handhelds don't (like the DE-5000).Best,

author: indman
author_rank: Super Contributor
timestamp: June 03, 2024, 05:02:31 pm
content: Quote from: mawyatt on June 03, 2024, 04:02:45 pmYou are wrong, the DE-5000 can show Z, otherwise there would be no point in this chipset.The DE-5000 displays much more information when connected via USB to a computer.Here is an example of such measurements

author: mawyatt
author_rank: Super Contributor
timestamp: June 03, 2024, 05:52:04 pm
content: Quote from: indman on June 03, 2024, 05:02:31 pmThis isn't about having a computer to read the LCR meter and computer then display results on something else, what's the point of a handheld with a computer dangling on a USB cable to read/compute/display the results!!The DE-5000 we have can NOT DISPLAY Z , at least the DE-5000 we have.Can anyone post an image of aDE-5000 that shows Z on it's display??Best,

author: indman
author_rank: Super Contributor
timestamp: June 03, 2024, 06:04:27 pm
content: The DE-5000 can display Z as well as other important circuit parameters at a resolution not available on the built-in display when connected to a computer!!! The fact that it does not show this data on the display does not diminish its value as a full-fledged LCR meter. Whether you take advantage of these opportunities or not is up to you. I, for example, use it and I don't suffer from it at all.

author: mawyatt
author_rank: Super Contributor
timestamp: June 03, 2024, 06:32:26 pm
content: Quote from: indman on June 03, 2024, 06:04:27 pmThe DE-5000 CAN NOT DISPLAY Z, as we stated!!Having to add another device to the DE-5000 does not diminish the fact that it CAN NOT DISPLAY Z directly!!If one wants the Z parameter, then one must attach a USB cable to the DE-5000, then connect to a computer, then start up the computer, then a communication program and so on. This is not the same as having turn on the the DE-5000 display Z stand alone in 5~10 seconds!! The information is available within the DE-5000 but the firmware does not support displaying Z!!Maybe the firmware will get an update and display Z and 1/Z, sure hope so, but in the meantime we'll just use our TH2830 or IM3536 when we need to display ZBest,

author: indman
author_rank: Super Contributor
timestamp: June 03, 2024, 06:37:41 pm
content: Quote from: mawyatt on June 03, 2024, 06:32:26 pmI don't have a TH2830 or IM3536, so I will use the DE-5000 for Z readings with a computer and USB cable if I need to examine the circuit in more detail.

author: mawyatt
author_rank: Super Contributor
timestamp: June 03, 2024, 06:49:38 pm
content: The DE-5000 is a great handheld, and we've said so many times!! The Special Chip Set utilized helps keep the cost down and reduces power consumption, important for a handheld, but does not perform any special measurement "magic", altho it's quite accurate as we've compared to our Lab Grade Bench LCRs many times.Inferring that it can DISPLAY Z is wrong tho, it can't and requires a computer and cable to display Z on something other than the DE-5000 itself!!The Special Chip Set limits the frequency range and frequency resolution, which I don't think can be improved by a firmware update. Hope to be proven wrong on this thoBest,

author: KungFuJosh
author_rank: Super Contributor
timestamp: June 03, 2024, 07:49:09 pm
content: I have the DE-5000, it was my go to LCR for years. The Shannon ST42 retired it. Then I got the (improved) ST2832, which is superior to all of the LCRs I've ever used...and I still use the ST42 (which has Z on the tiny display). DE-5000 is nice in its own right, but it doesn't compare...especially if you need to tether it to another device for useful functionality.

author: tautech
author_rank: Super Contributor
timestamp: June 03, 2024, 08:40:01 pm
content: ST42 is a great device and we are to market them in NZ and showed our sample to many at the recent EMEX show in Auckland. Many were surprised such a device could offer so much capability and several firm orders were taken.A week or so before when visiting member and buddy hendorog he got out his Agilent HH LCR meter to compare against ST42........a couple of minutes later,get me a setwas the firm reply.

author: Martin72
author_rank: Super Contributor
timestamp: June 03, 2024, 09:43:04 pm
content: QuoteAh, then everything is clear.I don't want to spoil your business, you know that.But you have to make things clear and one thing is that the ST42 (in my eyes) is not enough to cover everything, but that is exactly what is always suggested.The obvious thing is that mechanically alone you reach your limits when it comes to measuring normal wired components.

author: tautech
author_rank: Super Contributor
timestamp: June 03, 2024, 09:56:00 pm
content: Quote from: Martin72 on June 03, 2024, 09:43:04 pmFor 2 decades I have spread SMD tweezers wide enough to measure all manner of components.With ~50mm possible not much is exempt from obtaining a measurement and I have soldered wires on larger components .....In time you will find these capabilities.

author: Martin72
author_rank: Super Contributor
timestamp: June 03, 2024, 10:11:11 pm
content: If I buy the ST42, I will also test it and report on it, you should have that in mind.

author: KungFuJosh
author_rank: Super Contributor
timestamp: June 03, 2024, 10:17:02 pm
content: Quote from: Martin72 on June 03, 2024, 10:11:11 pm🤣🤣🤣 We all know it's when, not if. 😉I have no interest or benefit from praising the ST42, and I also believe they're great. Like any TE though, know it's uses and limits.Attached is the inductance measurement from when I was still using buggy firmware on my bench LCR. The ST42 helped with sanity checks and finding the issues (that were eventually corrected) in the bench LCR.

author: Martin72
author_rank: Super Contributor
timestamp: June 03, 2024, 10:39:08 pm
content: QuoteThe fact that I hate talking about things I don't know personally, unlike quite a few people who have no problem doing the exact opposite, makes the way I do my hobby a bit more expensive.But for the “good” of all forum members.And yes, I have just bought the miracle part for 143€.

author: KungFuJosh
author_rank: Super Contributor
timestamp: June 03, 2024, 11:03:41 pm
content: Quote from: Martin72 on June 03, 2024, 10:39:08 pmI've made a few of those purchases. Some of them are your fault! 😉

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: June 04, 2024, 01:25:33 am
content: I didnt know the de5000 had an app, i dont mind using an app to see all that extra info.. im going to look in to it a little more, the screen shots of that app make it look like the best bet. Do i need to buy/make an ir thing to use the app or can will it work via USB?Using an app is still much less of a hassle than setting up a VNA and 50ohm fixture or Scope/AWG to bode plot it. I do wish it could measure smaller inductances, but that is gonna be a problem with any meter under 500 bucks.

author: mawyatt
author_rank: Super Contributor
timestamp: June 04, 2024, 01:31:36 am
content: Would be interesting to see how well the ST42 stands up against our TH2830, IM3536 and DE-5000. We have some precision SMD components that would make a nice comparison.Maybe we'll tackle this at some later dateBest

author: KungFuJosh
author_rank: Super Contributor
timestamp: June 04, 2024, 01:56:50 am
content: Quote from: mawyatt on June 04, 2024, 01:31:36 amSee my reply above #33. The ST42 is what I used to help compare and work through the buggy firmware I had on the 2832 before it got corrected. I could send you one of the test charts if you want, they're also in the bench LCR thread.Within it's specified limits, the ST42 was on point for everything I tested it with.

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: June 04, 2024, 02:13:52 am
content: Its nuts to me an impeadence analyzer or top end LCR meter still costs so much money! I mean fast ADC and DDS chips are so much cheaper these days. Hell you can buy a 6ghz 2 port VNA for 600 bucks, but no one makes a 100mhz Z/LCR meter for under a grand..

author: KungFuJosh
author_rank: Super Contributor
timestamp: June 04, 2024, 02:19:41 am
content: Quote from: rwgast_lowlevellogicdesin on June 04, 2024, 02:13:52 amDo you mean 100kHz? a 30MHz LCR will cost you around $20,000.

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: June 04, 2024, 03:20:08 am
content: No i mean 100mhz, my point is there is no reason a fast lcr meter is so much when a 6ghz VNA can be had realtively cheaply.

author: KungFuJosh
author_rank: Super Contributor
timestamp: June 04, 2024, 03:28:46 am
content: Quote from: rwgast_lowlevellogicdesin on June 04, 2024, 03:20:08 amShow me a 100MHz LCR for $1000 and I'll buy it. Also try looking at the hardware that goes into making either of those devices, you're comparing apples and Toyotas. I'm with you though, I wish a quality high frequency LCR meter existed for a reasonable price.

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: June 04, 2024, 03:41:04 am
content: If i were better at math i would take the project on.. it seems to me you could build one with a fast ADC, a Zynq, and some hi speed opamps. Thats what 300 in parts at the higher end...

author: tautech
author_rank: Super Contributor
timestamp: June 04, 2024, 03:48:12 am
content: Quote from: rwgast_lowlevellogicdesin on June 04, 2024, 03:20:08 amMilli Hertz ?Sorry but you are beyond help if you cannot make the effort to use the correct denominators on a technical forum.What example are you setting for others ?I'm outta here.....

author: indman
author_rank: Super Contributor
timestamp: June 04, 2024, 05:50:55 am
content: Quote from: Martin72 on June 03, 2024, 09:43:04 pmTotally agree with this opinion. I have ST42 and it is a convenient and good tool when you need to quickly find out the parameters of SMD parts.But it has, along with its advantages, also a number of limitations. For example, the upper operating frequency of the test signal is limited to 10kHz, unlike the DE-5000.Shannon has promised to release a 100kHz tweezers, we will wait for it. The HB15(16) smart tweezers, which were sold in the Russian segment, has an upper operating frequency of 250kHz test signal, which significantly extends its range of application. Yes, it costs twice(3) as much as the ST42, but it has twice(3) as much capability. The analog of this smart tweezers in your market is labeled LCR Reader-R2.https://www.lcr-reader.com/r2.html

author: indman
author_rank: Super Contributor
timestamp: June 04, 2024, 07:02:27 am
content: Quote from: rwgast_lowlevellogicdesin on June 04, 2024, 01:25:33 amCheck out this threadhttps://www.eevblog.com/forum/testgear/is-the-de-5000-software-useful/

author: coromonadalix
author_rank: Super Contributor
timestamp: June 04, 2024, 04:01:44 pm
content: for theses lcr prices and ranges, the DE5000 is more than enough, mastech have one based on the same ic's but more expensivehantek have 2 models, you have some TE430 series, some Keysight, Uni-T and many low mid models etc ...all of theses will do a good job up to 100 khzhigher than that you need bench based ones .... and you know the price will rise fastand yes some of them have control sw for them ....special cases like Sencore LC-102 103 can output up to 1kv for capacitors, but their prices are oooooff no SW for themhappy with an DE-5000 with open and short calibration on each power up ...but if you did really write milli hertz ..... that's another story

author: shabaz
author_rank: Frequent Contributor
timestamp: June 04, 2024, 05:24:32 pm
content: If the requirement is to measure at 100 MHz, then there's always the VNA. The accuracy is in a far more restricted measurement range, but at least it's affordable. Obviously doesn't replace a high-end (tens of $k) LCR meter. Another bonus being that if desired you could test the inductor in a bigger network as it will be used, e.g. filter, etc., rather than a component in isolation.The set-up time with the VNA is long, but it would equally also take time setting up a decent measurement with LCR or impedance meter. They all use fixtures and require nulling-ing out/calibrating, etc, for accurate results. LCR meter short/open procedure can take ages across the frequency range.Example screenshot shows a DIY wirewound inductor measurement (approx 400 nH) with a VNA, the dot shows the measurement at a spot frequency, and you can also see the resonant frequency.Back to the accuracy, sometimes that's not actually needed, as long as the circuit is tunable, and just as important (or more important) might be checking the ballpark at a frequency, and then measure the overall response or output in-circuit, with VNA or sig-gen, 'scope, etc.

author: chilternview
author_rank: Frequent Contributor
timestamp: June 13, 2024, 09:06:28 pm
content: Also if you're measuring at VHF, you could look at the HP/Agilent 4396B. It's always puzzled me why these weren't more popular, as not only are they a VNA, a spectrum analyser but also an impedance analyser. In the last mode, you can measure L,C,R,Z,theta, D, Q etc vs frequency from 100KHz to 1.8GHz. And also extract equivalent circuit parameters, e.g for an inductor not only the L but also series R and parallel C.Obviously for non-RF applications the bench LCR meter is going to be easier to use and more accurate, or handhelds like the DE-5000 for quick less accurate checks, it all depends on what you're trying to measure.