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Mains current measurement with Halleffect sensor?
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Windows9Professional:
Since I own a scope, I kind of always wanted to measure mains current. Today I asked myself, If it would be possible to make a reasonably accurate current sensing extension cord with a BNC connector for my scope.

Now I just wanted to ask, If measuring current with a halleffect sensor has any flaws, or is as easy as it sounds like

I already created a list for the components I need:

One cheap extension cord (with phillip screws)
A halleffect sensor
A BNC connector
a powersupply for the sensor (probably some 12VDC LED power supply which I will hide inside the extension if possible)(and also a accurate voltage regulator)

I already have the coil, but I'm not quite sure if 15 turns of 1mm insolated copper wire around a 1cm (diameter) ferrite core will do it. It generates near to no heat at 5A continuously.

So, is this as easy as it sound or are there some flwas in my plans?
 
MagicSmoker:
Flaws? Well, the Hall effect sensor requires power and a bog standard current transformer doesn't. You do get better high frequency bandwidth from the H.E. sensor if you are interested in the harmonic distortion of a load, but otherwise the current transformer is overwhelmingly preferred here.

EDIT: wait, whut?


--- Quote from: Windows9Professional on September 15, 2019, 11:31:40 am ---...
I already have the coil, but I'm not quite sure if 15 turns of 1mm insolated copper wire around a 1cm (diameter) ferrite core will do it. It generates near to no heat at 5A continuously.
...

--- End quote ---

What coil are you talking about here?
Kleinstein:
The system with a hall effect sensor works about as describes. The main downside of Hall effect sensing is that near by iron or other magentic material can effect the reading and there can be an offset, as the hall voltages are quite small. The sensor-circuit man also pic up some other signals.

For AC current, there is an even simpler variation, with a current transformer. This does not even need a power supply. Clamp on amp-meters work this way.

A 3rd way for measuring is a Rogowski coil - kind of inductive pic-up without a core. However this usually needs amplification signal forming.
Windows9Professional:
Thank you for your quick reply.

With flaws I meant something like f.e. a HES has non-linear output (which it luckily hasn't)

Yes, I am more or less interested in higher resolution

So, thank you for your reply
Windows9Professional:

--- Quote from: Kleinstein on September 15, 2019, 11:41:39 am ---The sensor-circuit man also pic up some other signals.

--- End quote ---

Like really low power signals (like RF) or nearby power lines in the wall?

A current sensing transformer would only work with AC and I planned to calibrate it with DC

I don't think I will go with the 3rd option, just because it is more complicated

Thanks for your reply
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