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How do I get my oscilloscope to read voltage correctly? (lemmy.world)
submitted 8 months ago by to c/askelectronics@discuss.tchncs.de
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I bought a cheap Hantek 6022BE to learn with and I'm just trying to measure some voltage to check if it's accurate. I'm using openhantek6022 https://github.com/OpenHantek/OpenHantek6022 and also hscope on android. I'm measuring a 19v laptop power supply with the 10x setting on the probe and also a set of leads with a 20x attenuator. When I measure the power supply with my dmm I'm getting 19.22V with the scope I'm getting much higher or lower depending on where I set the voltage per division. Both programs have a calibration function which I did.

20x attenuator showing 19.6v

10x probe showing 20v

10x probe with 2v per division setting only showing 9.81V

Hscope showing 19.9v

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[–] 4 points 8 months ago (1 child)

This seems like it's probably within spec (i.e. not a terribly accurate meter, but not far off).

One other thing to keep in mind is that the laptop supply will probably produce a slightly higher voltage without a load -- that is, you'd get a value closer to 19v if you were able to measure it while charging the laptop.

I'm just a hobbyist, so take this with a grain of salt, but it matches my understanding.

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  • [–] 3 points 8 months ago*

    Yes. First thing I'd do is question the 19.22V as well. Is it really 19.22V or is the power supply maybe outputting an arbitrary voltage up to 20V with no load?

    And I don't really get what the divisions are supposed to be on the graph? Seems it always shows a line at 7.6 div, no matter what you configured? Except in one case.

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