3 phase input supply to adc

[PRIYADHARSHINI PALANISAMY]

how can i give a ac input to bipolar ADC.?actually that adc has 3 channel pair input..

 

[Golden Electronics]

Attenuate signal such that its peak = ADC +ref voltage using resistor network. what is ur input voltage range?

 

[PRIYADHARSHINI PALANISAMY]

thank u.i m using 10 v ac

 

[udhay_cit]

Reduce the voltage to measurable range of ADC. You can use three resistor potential divider circuit...

 

[Golden Electronics]

if ur 10 V rms then peak = 10*1.4142=14.142V so peak = 7.071 & ur ADC +Ref = 1.5 Volt then attenuate signal upto 1.25v using op-amp / resistor also

 

[FvM]

I presume it's a pseudo-differential ADC input that requires positive common mode voltage on the differential pins. So additional biasing circuits are needed. Preferably buffer amplifiers should be used.

You also didn't tell if you want to measure the instantaneous input voltage with respective fast sample rate or use an analog circuit to convert it to DC (averaging rectifier or RMS circuit).

 

[PRIYADHARSHINI PALANISAMY]

yes i want to measure the instantaneous input voltage with respective fast sample rate for R,Y,B simultaneously using ads8568