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.
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