How to check multimeter accuracy.
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- čas přidán 6. 09. 2024
- In this video I try out some reference boards for voltage, resistance and capacitance to test m7ultimeter accuracy.
Lab Equipment and tools:
UNI-T UT210E Mini Digital AC DC Current/Voltage Clamp Meter: www.aliexpress...
BK Precision 390A Multimeter: www.zoro.com/b... XDM1041 Multi-Meter: www.banggood.c...
Resistance/Capacitance reference board: www.aliexpress...
Voltage Reference Board: www.aliexpress...
There are many variables to consider when making measurements of any kind. Some of the cheap multimeters are more accurate then even a Fluke multimeter. The calibration on most multimeters is in a chip which is more accurate than adjustable pots.
This is true but for the average hobbyist it would be hard to calibrate a multi-meter unless there are trim pots. I presume if it is done in software there would be a port somewhere on the multimeter which would have to connect with a computer using some sort of protocol which may or may not be published by the manufacturer.
Also, the wall wart that you use to power your voltage references will have all kinds of noise that will affect your reference. Best to power your reference from a big battery whose voltage won't be affected by the tiny current draw of your reference and power it on long before taking measurements so it may stabilize thermally.
I would guess that the meter input impedance also has an effect along with the test lead resistance. You should use the same test leads on each meter.
So sorry sir, may I humbliy ask you a question, in this case which one is reallyrje most accurate of all the multi meters in your video here?
I believe the B-k-Precision Multimeter is the most accurate, I do not have an expensive 6.5 digit multimeter at this time. The Chinese multimeters all seem to be based on similar chipsets and will almost always display something like 9.98V for 10 Volts. Probably good enough for most instances.
@@Tech-Relief Oh OK sir! Mime are those cheap china multimeter. And I order one few days ago just to test my ebike battery, which is 72v. In this case sir if I use those china cheap multimeter to test on my 72v ebike battery, may I have your guidance on, for china cheap multeter right? Test on 72v the reading will fall like how many volt? For example for charge is 84v, but on the china cheap multimeter I will roughly get to see like how many volt? I mean it should lesser by minus how many percent of voltage out of 84v? Because my plan is to charge it to 78v daily before I use my ebike.
I would not worry about it, the Chinese multi-meters should be accurate enough for this. I like the UNI-T multi-meters, they seem to be better quality and there is a UNI-T store on AliExpress...
They are all accurate to the nearest whole volt. Their precision varies within 0.1v. Why would everyday use require greater precision? Most everyday components have 5% -10% variance from their stated values. A 9V power source would work from 8v up to 10v within circuit tolerances. Forget the second decimal place. Unless your work requires precision.
Yeah, I guess I was not too clear what I was trying to find out actually. I was wondering how you would calibrate a multi-meter if needed. Are these boards useful for that? It is true that most meters are plenty good enough for general purpose use.
I am here because I am trying to find out how to calibrate my inexpensive VOM to balance and charge my solar system's lithium storage batteries. They are not cheap and can be toasted if I my VOM is off.
Rule number one when dealing with Chinese products: never believe their claims. I have a couple of voltage references from China which came with calibration sheets. Same calibration sheets with exact same values were posted by others. There's no agilent or fluke meter with which these references were measured. Someone just wrote some numbers close to expected value. Same for your resistor and capacitor board.
You might be right about the Chinese references. In this case it seemed to be relatively accurate but who knows. I guess at best using them ensures that you can adjust all your multi-meters to the same value. I have wondered however if there is anything we can use to make an accurate reference ourselves. I see some voltage reference chips available which claim to have an accuracy of 0.05% presuming they are laser trimmed or something. Might look into those in future.
Mine😂😂😂
My question is why do you own that many voltmeters😂😂
So I could evaluate them and make videos around them. Some I have had for years and now seldomly use others I needed because they had an interface so I could display their output on a PC screen so it could be captured when making videos.