Amplification RPICT7V1 Version 4

UNDER CONSTRUCTION...

Gain formulae

Given a desired Gain the Gain resistor Rg can be calculated as follow.

Rg = 100000/(G -1)

G is the Amplification Gain.
Rg is the resistor value in ohm.

or deducing the gain from the resistor will be using

G = 100000/Rg + 1

ADC Full Scale

The RPICT7V1 Version 4 uses 4.096V voltage reference for the ADC. Signals are centred on 2.048V. Therefore the waveform can have a max amplitude of 2.048V. We will call this Vadc/2.

Vadc = 4.096V

The relation between the peak voltage from the CT at full scale and the Gain is given by

G * Vct = Vadc/2

Vct - Secondary peak voltage of the CT sensor.

Vct = Irms*√2/Nt * Rb

Irms - Max rms current required at full scale. Nt - Turn Ratio of the CT sensor. Or number of turns. Rb - Burden Resistor

G = Vadc*Nt/(Irms*2√2*Rb)