Author Topic: [Very] Cheap USB multimeter or USB oscilloscope?  (Read 1472 times)

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Offline kalel

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[Very] Cheap USB multimeter or USB oscilloscope?
« on: June 02, 2017, 10:20:38 pm »
Hi there,

The very low (bottom) range is probably not of much interest to most experienced people, but might be interesting to beginners with less knowledge and budget to invest (used market aside, some people can score really great deals used, but those vary by country and specific date).

With USB oscilloscopes going down to about $50-60 from China with shipping, and no idea about how much their USB multimeters are going for, assuming you can't get both, which of those two items would you find more useful for a true beginner?

Is a USB multimeter slightly cheaper to construct than an oscilloscope, and could that mean a potential better quality of usb multimeters vs oscilloscopes for a similar cheap price?

On the other hand, would a USB oscilloscope offer most of the functionality of a USB multimeter?

Maybe another way to ask would be if you had to choose one of these two item types, which would you choose. Edit: This might be a wrong way to ask since as not being a beginner, you might have different specific needs and low end gear could simply lack the functionality you need altogether.
« Last Edit: June 02, 2017, 10:23:21 pm by kalel »

Offline blueskull

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Re: [Very] Cheap USB multimeter or USB oscilloscope?
« Reply #1 on: June 02, 2017, 10:31:16 pm »
A DMM is way more precise than a scope. For most scopes, you get 8bit resolution, and 2% or even worse voltage accuracy.
For any decent DMM, you get at least 0.25% accuracy with at least 3.5 digit of resolution (say, a 4000 count DMM, you get ~12bit of resolution).
Some good handheld DMMs can get you 0.025% accuracy and 60000 count (~16bit of resolution). You won't easily get that from a scope for any reasonable price.
On the other hand, scopes sample at 10Msps+, while handheld DMMs give you up to 20 updates per second even for the very fast ones.

The bottom line is, they are not replacing each other. There are handheld DMM+scope combos, but usually they suck at either function, but barely provide "just enough" usability.
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Offline kalel

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Re: [Very] Cheap USB multimeter or USB oscilloscope?
« Reply #2 on: June 02, 2017, 10:41:09 pm »
Thanks. Well I assume the bottom line products of either category aren't perfect performers, I'm just trying to determine if there are any reasons why one of the two types might be of better quality for a similar price (e.g. needs less expensive hardware, can work with cheaper parts, etc)

Which item type would be more useful to a beginner is probably as important as well, but you can get handheld multimeters (non-usb) very cheaply, and you can't get oscilloscopes for that price. Actually, there are those $16 DSO kits, but they seem to be much more limited than the $50 USB units.

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