SCT013 50A - Low current

[carlos sampaio]

Hello,
I'm using the basic config to read at serial monitor the current from my loads(resistive).
The setup is an arduino UNO(Emonlib running) + SCT013-50A with classic voltage divider+capacitor 10uF.
I can see currents with good acuracy only above 1A, so its my question...
How can I read currents like 30....100mA?
Thanks in advance
Cheers

[Puneit Thukral]

@carlos-sampaio said in SCT013 50A - Low current:

SCT013

I would be interested to know this as well, but to my understanding - maybe it has something to do with resolution. I had earlier used this calculator to calculate the value of resistors and capcitors for my 30A CT Clamp. But the calculator is no longer opening.

There are lower capacity CT clamps available and perhaps those can measure smaller currents. It is possible that the mA current is smaller than the threshold to excite the coil inside it.

[carlos sampaio]

I just got some info about this sensor...it can't read low currents due it features of construction, the best accuracy would be +- 5-50A range.
But I really need to read low currents like 100mA for example in my project :/
If I use 2 arduino pins to read 2 non invasive CT's with different ranges probably the CT used to low current will be broke when the current gets high...like 20-30A.

[Puneit Thukral]

I think you can try this

[carlos sampaio]

Hey,
Thanks for that info, very interesting. But I think too complicated to get it here in Brazil.
I had a new idea, will put here today or tomorrow because it depends from a answer of emonlib config.

[Yveaux]

@carlos-sampaio there are a number of alternative current sensors that could fit your application and are available on breakout modules, e.g. from AliExpress or EBay: ACS758, ACS712, INA219
Maybe some of them can be sourced in Brazil.

[carlos sampaio]

@Yveaux thanks,
I have ACS712 for 5 and 30A but it has 66mV/A, would be complicated to use it with arduino uno :/
I will try to use a ct 5A + opamp like ina122 and try to read at least 100mA - 2.5A, after that I will read using the SCT model.