How do I design a low pass filter for an Fc = 4000 Hz and a high pass filter for Fc =2000 Hz?

Answer 1

1. RC Low-pass Filter
Fc = 4000 Hz.
R = 2000 Ohms(selected).

C = 1/(2pi*F*Xc)=1/(6.28*4000*2000) =
2*10^-8 Farads. = 0.02 uF.
The output is measured across C.

2. RC High-Pass Filter.
R = 4700 Ohms(selected).

C = 1/(6.28*2000*4700) = 1.69*10^-8 Farads = 0.0169 uF.
The output is measured across R.