Question about Multimeters

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I was thinking of buying a multimeter. The one that I intend to buy is this: https://www.electroncomponents.com/Digital-Multimeter-MAS830L

I haven't used multimeters a lot. This is the dial of the one that I want to buy:

EC_MAS830L_1-500x500.JPG


Let's take a specific example of the AC voltage section. It has two parts: 200V and 600V. Do these values mean the maximum possible measurable value when the dial is in that position? For example, if I try to measure 220V AC with the dial in 200V position, it is supposed to give an out-of-range error, right?

What if I measure 100V AC with the dial in 600V position? Will there be any problem with accuracy?

Similarly, what would be the result if I measure 2Ω resistance with the dial in 2M position? Are these multipliers, like the multiplier band on resistors?
 

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  • #2
eq1
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  • #3
tech99
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I was thinking of buying a multimeter. The one that I intend to buy is this: https://www.electroncomponents.com/Digital-Multimeter-MAS830L

I haven't used multimeters a lot. This is the dial of the one that I want to buy:

View attachment 236937

Let's take a specific example of the AC voltage section. It has two parts: 200V and 600V. Do these values mean the maximum possible measurable value when the dial is in that position? For example, if I try to measure 220V AC with the dial in 200V position, it is supposed to give an out-of-range error, right?

What if I measure 100V AC with the dial in 600V position? Will there be any problem with accuracy?

Similarly, what would be the result if I measure 2Ω resistance with the dial in 2M position? Are these multipliers, like the multiplier band on resistors?
If I may just expand slightly on the information provided by eq1, can you visualise the analogue version of the multimeter (which can be purchased, of course)? The various ranges indicate the maximum that can be read before the needle hits the top of the scale. On the other hand, if you set the range too high, the needle hardly moves and so accuracy is poor. With the digital version, it can cope much better with low readings, but it is best to set the range just above what you are measuring.
 
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  • #4
berkeman
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The one that I intend to buy is this:
Does the dial imply that the meter does not measure AC current? That's probably not a big limitation, but it would depend on the uses that you can foresee for the meter.
 
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  • #5
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Does the dial imply that the meter does not measure AC current? That's probably not a big limitation, but it would depend on the uses that you can foresee for the meter.
Nope, it doesn't. AC multimeters that measure current are quite costly, and generally come with a clamp. Since I am going to use it mostly for DC measurement, this one will suffice at the moment. :smile:

Edit: In fact, there are better ones that can measure temperature, capacitance, inductance, etc. As you might gauge, those are costlier than the clamp meters.
 
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  • #7
davenn
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Edit: In fact, there are better ones that can measure temperature, capacitance, inductance, etc. As you might gauge, those are costlier than the clamp meters.
capacitance and inductance are very handy things to be able to measure .... consider saving a little more to get one that does
 
  • #8
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I was thinking of buying a multimeter. The one that I intend to buy is this: https://www.electroncomponents.com/Digital-Multimeter-MAS830L

I haven't used multimeters a lot. This is the dial of the one that I want to buy:

Let's take a specific example of the AC voltage section. It has two parts: 200V and 600V. Do these values mean the maximum possible measurable value when the dial is in that position? For example, if I try to measure 220V AC with the dial in 200V position, it is supposed to give an out-of-range error, right?

What if I measure 100V AC with the dial in 600V position? Will there be any problem with accuracy?

Similarly, what would be the result if I measure 2Ω resistance with the dial in 2M position? Are these multipliers, like the multiplier band on resistors?
A have a multimeter of same series. It is generally fine, tolerant to out-of-range input and do not require user to calculate multipliers to displayed value (accuracy may suffer if you select wrong range though). It has 2 deficiencies:
1) No auto power off, therefore battery runs out in few days if you forget to power off after work
2) Quality of short-circuit audio signal is poor, difficult to hear in noisy environments
 
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  • #9
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capacitance and inductance are very handy things to be able to measure .... consider saving a little more to get one that does
Since you have advised, I started searching for a good one with all the functions. What I found is this:
  • The ones available on Anazon doing all the functions are of almost the same price as the one that I linked, but there are terrible reviews, like bad soldering, low accuracy, low range and defective product. See these: #1, #2, #3 (the second and third ones can measure AC current as well)
  • Otherwise, the LCR meters are quite overpriced. See this one (about 57 USD + shipping)
  • The clamp meters cannot measure DC in general, or give a low range and low accuracy.
If you find one that is reasonably-priced and has good reviews, it would be helpful if you post a link.
 
  • #10
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Since you have advised, I started searching for a good one with all the functions. What I found is this:
  • The ones available on Anazon doing all the functions are of almost the same price as the one that I linked, but there are terrible reviews, like bad soldering, low accuracy, low range and defective product. See these: #1, #2, #3 (the second and third ones can measure AC current as well)
  • Otherwise, the LCR meters are quite overpriced. See this one (about 57 USD + shipping)
  • The clamp meters cannot measure DC in general, or give a low range and low accuracy.
If you find one that is reasonably-priced and has good reviews, it would be helpful if you post a link.
Well, handheld LCR meters do exist but have niche applications of very approximate parts identification or binning (the LCR metering is poorly compatible with having meter-long leads of standard multimeter) - therefore production batches are small and prices are higher. Economy of scale in operation.
A6243L (please search on ebay or amazon) LC meter may be a good addition to multimeter though. Reviews indicate good cost/performance for low-cost meter.
 
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  • #11
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AC multimeters that measure current are quite costly, and generally come with a clamp.
Erm, no. The clamp is there to measure current without breaking the circuit. The ones you linked previously all could measure AC current without clamp (you need to install them into the circuit). Most types can measure AC current. It is only the clamp what is costly.

Is this your first one? It is completely OK to start with a cheap one with limited knowledge. Even if you buy another later on a basic one will come handy.

I think AC current measurement would be useful anyway, but for cheap I'm against the capacitance measurement. It is just not reliable within the 'cheap' category by my experience.
Also, for cheap ones I prefer having 'cheap looking' ones :smile: You just won't take them too serious and won't forget to suspect the multimeter if something is not right.
 
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  • #12
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Erm, no. The clamp is there to measure current without breaking the circuit. The ones you linked previously all could measure AC current without clamp (you need to install them into the circuit). Most types can measure AC current. It is only the clamp what is costly.
By AC multimeters, I wanted to mean those which measure AC current. Majority of them are the ones with a clamp. The ones that come without a clamp, have odd ranges. For example, 20mA, 200mA, and then suddenly 20A. I doubt whether the ones without a clamp would do a good measurement.
Is this your first one? It is completely OK to start with a cheap one with limited knowledge. Even if you buy another later on a basic one will come handy.
This is the first one that I am buying by myself. I have used both clamp type and the normal one previously, but that was under supervision. I didn't quite play with the ranges, since most measurements that I did were of low value.
I think AC current measurement would be useful anyway, but for cheap I'm against the capacitance measurement. It is just not reliable within the 'cheap' category by my experience.
That's what Amazon customer reviews say too. :smile:

Do you have any preference for LC meters? I might buy them later.
 
  • #13
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Also, for cheap ones I prefer having 'cheap looking' ones :smile: You just won't take them too serious and won't forget to suspect the multimeter if something is not right.
Hmmm!

Having used cheapo meters for many years, I would say that troubleshooting a machine/system is hard enough without having the extra cognitive load of worrying if your meter is telling the truth.

The UNI-T UT 204A is an AC/DC clamp meter with most of the functions you’ll need for starting out. I have one to back up my main meter and it’s extremely useful. No one meter has all the functions you need, so you’ll end up with several anyway...
 
  • #14
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The ones that come without a clamp, have odd ranges. For example, 20mA, 200mA, and then suddenly 20A.
That's because the low ranges are 'fused' ranges, so no danger of overcurrent. At least, that's the theory. For the high current range the shunt is practically a thick piece of wire, so no fuse there. They do an acceptable measurement, if the frequency is low enough (a few hundred Hz at most).
Actually, I think the 20A range is the most useful. The low ranges are just too fragile and you are good if it's just the fuse. But to have a safely boxed (!!!) 20A shunt which can measure - that worth a lot for a beginner.

Do you have any preference for LC meters? I might buy them later.
Then just don't rush and let your own preferences develop based on the tasks you pick.

Having used cheapo meters for many years, I would say that troubleshooting a machine/system is hard enough without having the extra cognitive load of worrying if your meter is telling the truth.
I've started with one which barely worth 5USD that time ( ~25 years ago), and right now I have exactly the same problems on an equipment worth around 3000 USD :smile:
 
  • #15
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I've started with one which barely worth 5USD that time ( ~20 years ago), and right now I have exactly the same problems on an equipment worth around 3000 USD :smile:
For example: Cheap meters come with cheap leads... I once spent longer than I care to admit trying trace an intermittent 5V rail to a crank sensor, only to find it was the meter lead (newish) which had broken internally, and the sensor supply was fine.

Another: measuring current draw somewhere that seemed to be defying physics, only to find the meter’s current shunt solder joint had cracked and gone high resistance.

Another: voltages in an inverter which were way off, but consistent. Another meter gave more sensible readings. I guess the little blob chip had got corrupted somehow, or perhaps the resistor array...

Better kit is certainly not guaranteed to do this sort of thing, but my ‘good’ meter has never let me down like that, except for one issue: it defaults to AC current when switched to current range:

“The (DC) machine is running normally, but there’s no current! Where IS it?!........ Oh, right.”
 
  • #16
anorlunda
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Instead of new but cheap meter, what about a used Fluke meter from someplace like Ebay? Those things are reputed to last forever.

What buyer beware warnings should one be aware of for used Flukes?
 
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  • #17
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Instead of new but cheap meter, what about a used Fluke meter from someplace like Ebay? Those things are reputed to last forever.

What buyer beware warnings should one be aware of for used Flukes?
That’s exactly what I did - started with a used Fluke 87 III, but found the upper capacitance range was too low, so sold it and found a used 87V.

The range of features on Flukes is generally quite modest, as is the digit count compared to other premium brands, but what’s there performs well and is stable. The safety features are top-notch.

From distant memory, some Flukes, possibly 87s, suffered from screen failure related to the zebra strip, and others had a problem where the firmware could get corrupted by EMI. In general, these are industrial quality meters and are often in a condition that shows that.

In any case, good sellers will take lots of photos of the meter in various modes to show the screen works, etc.
 
  • #18
sophiecentaur
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Nope, it doesn't. AC multimeters that measure current are quite costly, and generally come with a clamp.
The cheap AC clamp meter is based on a current transformer and can be very useful for fault finding on home mains equipment. The more expensive DC clamp meter is based on Hall Effect and (for £100+ ) can be incredibly useful for automotive applications. You can measure charging currents of less than 100mA without disconnecting the battery. You can see how much current the starter motor is taking and nothing else will do that for you.
Whatever DMM the OP buys, there will be some requirement down the line that it won't satisfy. By then he may be rich enough to buy a better one.
If a cheap meter doesn't wear out or break then it hasn't been used enough to justify not having spent more on a better one.
 
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IMO if you can spring for an auto ranging meter, that'd be the way to go, its irritating to have to click through ranges in resistance, as an example, to figure out of you are actually open circuit or just out of range..

To me at least, I'd concentrate on the main functions for a meter, AC/DC volt/current, diode check, ohms, continuity. A good mV range is also useful, then you can measure what ever currents you want (with a shunt resistor). I would leave the capacitance/inductance measurements to a dedicated LCR meter, and temp sensing to a stand alone device. Eg you may want to monitor temps over time so having a data logging function might be nice as well as not tying up your meter.
 
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  • #20
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The cheap AC clamp meter is based on a current transformer and can be very useful for fault finding on home mains equipment. The more expensive DC clamp meter is based on Hall Effect and (for £100+ ) can be incredibly useful for automotive applications. You can measure charging currents of less than 100mA without disconnecting the battery. You can see how much current the starter motor is taking and nothing else will do that for you.
I read about those in Wikipedia. However, I found that there are very low number of instruments that has all the functions. The AC clamp meters within my budget at this moment cannot measure DC current (not even through probes), while DC meters cannot measure AC current. There is one that I found which does most of the functions: Mastech MS2101 Digital AC/DC Clamp Meter, but I don't know whether the clamp works for DC as well (someone needs to help me on that).

There is, however, Fluke 362 clamp meter, that is capable of doing almost everything, except capacitance and inductance, transistor check and diode test. The user manual indicates that the clamp can measure DC current as well.

What I am thinking is, as @sophiecentaur and others have suggested, let me buy a cheap one at this moment, because I will be working on a project that will cost around 3000 INR, and spending another 3k for multimeter may not be possible at this moment. However, based on the guidance I have received here, I'll buy a better one after a month or two.

Edit: The Mastech website and the user manual say that the one mentioned above works as DC clamp meter also. So, I prefer it over the Fluke that I mentioned above.
 
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  • #21
sophiecentaur
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let me buy a cheap one at this moment,
A good solution. If you end up buying a better one in time, you will then own two. No problem with that scenario at all. At the moment, I have two. One in the house and one in the shed. The cheap one will still tell you if your battery is flat or that the mains socket is powered etc.. 95% of measurements are of that kind. and your 'nice' meter gets looked after better. (When you have one.)
 
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  • #22
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Exactly. When electronics gets serious it takes lot of meters. For the last measuring session here I had eight displays on my desk (including the ones on the PSUs), just for the basic voltage/current values. So for the first one, you don't have to be too picky.
 
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