how can I calculate de valor of the resistor and the capacitor to low past filte

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1

Heiii guys,
I’m student and I’m doing my final project of de degree and now I’m writing the memory, but I have a very important problem. My project is a measurement of a sensor with an amplifier model TL084, a filter and a A/D converter. This circuit is powered with a power supply, DC 5V and 12V.
My problem is, how can I calculate de valor of the resistor and the capacitor to the circuit?. Because one day my teacher said me the values of the resistor and the capacitor, in a low past filter, but I don’t know this values
Rfilter = 500k and C= 100nf

Thanks

2

The time-constant of an RC filter is RC, and the frequency of the 3dB roll-off point is 1/(2pi RC)