Amplification RPICT7V1 Version 4: Difference between revisions
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Vadc = 4.096V | Vadc = 4.096V | ||
The relation between the peak voltage from the CT and the Gain | The relation between the peak voltage from the CT at full scale and the Gain is given by | ||
G * Vct = Vadc/2 | G * Vct = Vadc/2 | ||
Revision as of 21:16, 7 April 2019
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
G = Vadc*Nt/(Irms*2√2*Rb)
Here we have
Irms - Max rms current required at full scale. Nt - Turn Ratio of the CT sensor. Or number of turns. Rb - Burden Resistor