# How to connect a CT-sensor to an Arduino Giga?

#### Ian0

Joined Aug 7, 2020
9,535
Well i need the current to calculate the power in KW.

But for my own vision, the Amplifier will give voltage around 1v to the Arduino linear to it's measured current right. And i have to put that to RMS to know the exact current right?
Well that's easier that if you wanted to know the voltage and the current separately.
All you have to do is sample, (You will need at least 16 samples per cycle) multiply the instantaneous voltage by the instantaneous current and average the result (a 1st order IIR filter will do the job). No need for any squares or square roots.

#### Rensieboy223

Joined Feb 3, 2024
37
Well that's easier that if you wanted to know the voltage and the current separately.
All you have to do is sample, (You will need at least 16 samples per cycle) multiply the instantaneous voltage by the instantaneous current and average the result (a 1st order IIR filter will do the job). No need for any squares or square roots.
Yeah i know the voltage already on my system, that's 400AC. I only need to measure the current.
But i have the schematic, but what kind of signal does the Amplifier give to the Arduino?

#### Ian0

Joined Aug 7, 2020
9,535
Yeah i know the voltage already on my system, that's 400AC. I only need to measure the current.
No you don't! Power = Voltage * Current * power factor
but what kind of signal does the Amplifier give to the Arduino?
from post #26. . .
The input at the processor is a steady 1.65V with no current through the CT.
With 100A through the CT the input to the processor will be a sinewave with a positive peak at 1.65+1.41V and a negative peak at 1.65-1.41V

#### Rensieboy223

Joined Feb 3, 2024
37
No you don't! Power = Voltage * Current * power factor

from post #26. . .
The input at the processor is a steady 1.65V with no current through the CT.
With 100A through the CT the input to the processor will be a sinewave with a positive peak at 1.65+1.41V and a negative peak at 1.65-1.41V
Okay, so i also should measure the voltage on my 3 phase setup. So i need the measure the voltage 3 times because i have L1, L2 and L3.

Okay, but how do i get the sinewave into exact amperes?

#### Ian0

Joined Aug 7, 2020
9,535
What is your final application ?

#### Rensieboy223

Joined Feb 3, 2024
37
What is your final application ?
A complete automated Oven system. We already have the control, we only want to measure the current extra.

By the way,
Do you know where i can find the exact schematic for the WCS1800? I can buy a module to measure the current, but want to make my own schematic to connect 3 sensors in one PCB?

#### Ian0

Joined Aug 7, 2020
9,535
I would have thought that oven elements were nichrome wire which have a very low temperature coefficient of resistance, and they are resistive loads with unity power factor.
So won't the power simply be V^2/R with no need to measure the current?