### Calibration constants

Hi, I've been reading the documentation here on OEM for the past couple of days and its really insightful. Thank you for putting this out here.

For the current measurement, I'm using a Bourns 53150C current transformer with a turns ratio of 1:150. Datasheet is available here. This is rated for 10A maximum current. Now my ADC can tolerate upto 1.5V on its input and hence for the rated current of 10A I need to output 1.4V. This gives me the R(burden) value of 21R.

Hence,

Current Constant = (10 ÷ 66.67m) ÷ 18 = 8.333.

[Isec = Ipri x Npri/Nsec = 10 x 1/150 = 66.67m]

Is this calculation correct?

Also I don't quite understand how this line in the voltage constant description is derived:

voltage constant = 230 × 11 ÷ (9 × 1.20) = 234.26

Any help would be really appreciated!

### Re: Calibration constants

It is all spelled out in the Building Blocks page about Calibration theory. It's only the voltage ratio from your ac adapter = 230 ÷ (9 × 1.20) and the voltage dividers (11)!