Hi
I was wondering if anyone can suggest me a sensor module to measure low AC current with 0.1mA resolution and lowest value. As I couldn't find any that could achieve this value..
Be more specific. Are you looking for peak current or RMS current?
Frequency.
Sine wave, or other.
Floating, or common ground.
Leo..
Does an ECG or EEG sense current change or voltage change?
Neither. The use EMF radiated from the conductor.
Hi paul
RMS please.
Hi wawa
50hz
Sinewave
Doesn't matter
A current transformer followed by a bridge rectifier will give you a DC voltage equal to RMS current. Calibration must be done
I want to log some current and voltage readings for some simple electrical circuits to the PC to show them on a DAQ software and low current and voltage readings are required..
Thank you again..
For a maximum current of 2A or 1A and if I need to measure currents as low as 0.1mA could you suggest me some components and if possible the circuit please?.
Is there some readily available modules that could achieve this?
0.1 mA on a 2A range represents a range of 20,000. You won’t get that with hobby parts and find it very hard to find any part commercially for AC current .
For example : The fluke 87v multimeter is accurate to 1% on ac current ranges +- 2 digits ( on 2A , range , that’s 10mA) , it costs around £800.
You can get better on selecting lower ranges , say the 10mA full scale - but you need to think how you would achieve that in your project and change ranges .
You need to decide why you want such high accuracy , what is the project that needs that ?
Best applicable bits , IMO are National instruments , looking at £1000’s tho , and might not meet your spec.
Your electricity meter won’t see that low current
thank you for this enlightening reply.
You are right this seems to be too much to ask for. After thinking more about it I am interested in lower currents from 1mA to several hundreds of milli amps, can you please recommend me a good AC current sensor that can be found within the hobbyist category?
What do you guys think about using a combo of a current transformer such as ( YHDC SCT006T )and a precision bridge rectifier module like this one: Bridge
Would that work directly and give a 0-5v analog signal or need additional processing ?.
Thank you
Hi,
If you do use a current transformer, you can pass the AC current carrying wire through the toroid more than once.
Pass it through twice and that increases the response by two.
five times through == response by five.
There will probably be a limit, but you need to EXPERIMENT.
Tom..
Hi Tom
If I got you right I think you mean this increases the turns on the primary side. I just searched for that and I wasn't aware of it at all..
Many thanks...
Hi,
Yes....
Tom...
Okay. An inductor rather than input/output current or +/- voltage differences. Would this method not work with measuring changes in flowing micro-current? An inductor is a standard electrician tool.
Explain,please. An inductor is an inductor because it partially or completely encloses it's own magnetic field. The is where the name comes from.
Why a rectifier. The A/D of an Arduino can measure AC directly.
With a 5Amp CT and the 10-bit A/D of a common Arduino, resolution is 5000 / 1024 = 5mA.
You need 50 turns through that CT to get to a 0.1mA resolution. Not good.
Measuring across a shunt (resistor) would be much easier, but I see you're measuring mains. That must be done fully isolated, for safety. Meaning the whole Arduino circuit must be in a closed box with screwed on lid. And wireless connection to the outside world. Not an easy task, and dangerous for a beginner.
Leo..