LPF (1)

Design of the LPF and Amplifier Low Pass filter The filter used in this case was a 2 nd order low pass Bessel filter using Sallen-Key topology with 10 Hz cut-off frequency. If C 1 and C 2 are selected to be 2.2μF and 4.7μF respectively R1 = 1.94kΩ, R2 = 7.9kΩ However considering availability, the selected resistor values were, R1 = 2.2kΩ, R2 = 7.4kΩ Non-inverting amplifier The following non inverting amplifier design was used for the hardware Non inverting amplifier Selected gain = 10 R 2 was selected as 5kΩ R 1 = 555.56Ω Due to availability the R 1 for the non inverting amplifier i s selected to be 500Ω which changed the gain to 11. This minor mismatch of result does not affect the output.