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Mains current measurement with Halleffect sensor?

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Windows9Professional:

--- Quote from: MagicSmoker on September 15, 2019, 11:35:53 am ---EDIT: wait, whut?

What coil are you talking about here?

--- End quote ---

Some copper wrapped around a ferrite core (not that one out of a transformer, just a ferrite stick)

But I can easily increase the turns on it if the magnetic field wouldnt be strong enought

MagicSmoker:

--- Quote from: Windows9Professional on September 15, 2019, 11:48:13 am ---...
A current sensing transformer would only work with AC and I planned to calibrate it with DC
...

--- End quote ---

This makes no sense, really. A mains-frequency current transformer won't need calibration since its output will be as precise as the value of the burden resistor and the turns ratio, and will range in price from 3-15 Euros depending on form factor and current range. For example, this part from Triad Magnetics has a 1:500 ratio and max primary current of 30A for $3.37:

https://www.digikey.com/product-detail/en/triad-magnetics/CSE187L/237-1103-ND/242546

Just wire a burden resistor across the output to convert the secondary current into a voltage and read directly with your scope. For example, a 50 Ohm burden resistor will give 3V out with 30A through the primary. Easy-peasy.

Windows9Professional:

--- Quote from: MagicSmoker on September 15, 2019, 01:15:37 pm ---
This makes no sense, really.
--- End quote ---

... Oh, you're right.. To be honest, I didn't notice that bevore...

Does a CST blur out all detail of the current waveform or is there at least some detail? (f.e. when measuring a switch-mode power supply, there's some switch noise as far as I know)

Edit: the example above is bullshit... I mean when measuring f.e. an iron-core transformer

schmitt trigger:
The downside of a CT, is that it can’t measure DC, or AC with a DC component. Otherwise they are very sturdy and don’t require external a power  source.

Cheap CTs will also have some bandwidth limits, but there are good wideband CTs, although they are not cheap. 

https://www.pearsonelectronics.com/

To your idea of hall-cell sensing; Allegro Microsystem and others already have such devices. The beauty of such devices is that it incorporates the features and processing circuitry required to make an accurate IC current sensor.

MagicSmoker:

--- Quote from: Windows9Professional on September 15, 2019, 04:44:59 pm ---Does a CST blur out all detail of the current waveform or is there at least some detail? (f.e. when measuring a switch-mode power supply, there's some switch noise as far as I know)...

--- End quote ---

The cheapest current transformers with plain old laminated silicon steel E cores (like the one I linked to previously) won't have terribly high bandwidth so wouldn't be ideal for observing the waveform into something that draws peaky currents with high harmonic content, like a switcher. If that's what you want to do then a Hall effect sensor intended for mains applications like the ones from Allegro that @schmitt trigger mentioned would be better.

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