How were you measuring these values?
which values, values of resistor ?
These values
for values of my CT i measure them using my arduino code or using my logic analyzer, and for the exact values i use multimeter to compare between them
The voltage output from the CT is very small. If you measure 10A, the voltage will be 40mV.
You won't be able to measure that with an Arduino, with any accuracy.
How accurate is your multimeter can it even read low voltages?
That 50:1 CT, with a 1ohm burden resistor, gives 1volt AC @ 50A,
The 1 * 2 * 1.414 = 2.8volt peak/peak seems a perfect match for the input of a 3.3volt processor.
I don't see how that could damage the CT.
I think only linearity suffers a bit if you don't load a CT with (ideally) zero ohms.
Leo..
Hi,
Can you please post a circuit diagram showing your circuit from which you took your latest measurements.
Please show where you measured.
Can you post some images of your project?
So we can see your component layout.
Thanks.. Tom.. 
Readings without a burdon resistor are meaningless.
I don't know what you are using to measure the voltage but maybe you have reached the noise limit of that instrument. 11mV is very small.
You also need to take into account the resistance of the wire you are using.
No, i didn't say without burden resistor, i said without load, it means without any device to measure, so it should gives 0A or 0.001 A (a noise) not 0.11A or 1 A for 0.2 ohm resistor
Way too big, will give very inaccurate readings.
If you have no device to measure, then how do you know what the voltage is?
Hi,
What logic analyser?
39.891mS >---> 25Hz
Thanks.. Tom..
i tried also 1 ohm and 0.2 ohm and the same thing
Logic analyzer of Saleae : Saleae Logic 8 Logic Analyzer
Using anything other than 0.2 will result in errors. As I said you won't be able to measure the voltages with an arduino without amplification
As I said that current transformer was a bad choice.
With no current flowing.
I think you are over thinking, you will get noise, I can tell from the 25Hz that you have 50Hz mains power, that is what your current transformer is picking up.
What resolution do you want to read you current at?
1A, 0.5A, 0.1A?
Tom..
Maybe, but even i cannot get exactly 0.2 ohm.
And i have no choice for choosing this CT
Hi,
Can you get 0R1 or 0R4 or even 1R0 resistors, and make your burden resistor.
What can you get?
You only need to scale your controller conversion equations to suit your burden resistor.
You may need to trim your equation to calibrate.
0R1 + 0R1 = 0R2.
or
0R4 in parallel with 0R4 = 0R2.
Tom..