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Anybody with siglent multimeter ?

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tonycstech:
I have  SDM3045X desktop multimeter from siglent and i am having misunderstanding about its reading of resistance.

I have a circuit that has 900 ohms.
In automatic mode, it will set its self to 600 ohm range and measure 500 ohms for what ever reason.
If i manually set range to 6K, it will still give me 500 ohms reading.
If i set it to 60K range, it will give me correct 900 ohms.

Every multimeter i have, digital or analog, all read 900 ohms manual or auto.
This one reads 500 unless i set range at 60K or higher.

What am i measuring ?
I dont want to get into this rabbit hole because it shouldn't matter when every other multimeter measures this correctly.
But in case you are one of those, i am measuring resistance of a circuit containing buck converter.

bdunham7:
Your circuit is interacting with the current source of the meter and doing....something?  Is there an inductor in the part of the circuit you are measuring?  Or a junction (diode or other) that could be conducting?

tonycstech:
There is a coil.
I am measuring video card main power phases.

I contacted tech support they are not very helpful and i am trying to get an RMA but it takes almost a week to get a reply and does not seem to go anywhere for weeks now.

bdunham7:

--- Quote from: tonycstech on May 16, 2022, 05:50:19 am ---I contacted tech support they are not very helpful and i am trying to get an RMA but it takes almost a week to get a reply and does not seem to go anywhere for weeks now.

--- End quote ---

I doubt that the meter is 'broken', so an RMA will likely just result in more confusion.  And even if it is defective, getting them to do anything about it will require an explicit explanation of what is wrong.  What you refer to as going down the rabbit hole is just understanding what DMMs do when they measure resistance.  The fact that this one appears to give you what you think is an incorrect result while others are correct may be a design quirk or defect--or it may simply be the result of different meters using different test stimuli.  I have a sneaking suspicion from other discussions that your meter has a combination of both due to the way ranges are set up.

What you need to do first is put a high-impedance voltmeter in parallel with the DMM that is testing resistance.  If you don't have any high-impedance voltmeters, a 10M input (most handhelds) will be fine at this low of a resistance.  Try measuring the voltage across the test resistor during the resistance test with the Siglent and then at least two of the meters that give you correct results.  You can also confirm the test current by connecting the Siglent to another DMM set to measure (small) current and then measuring the resulting current when you manually select each resistance range on the Siglent.  Post your results and we'll go from there.

Grandchuck:
Do you have ordinary resistors available?  If so, check them with your meters.

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