♦Filters
RC LPF
RC HPF
LR LPF
LR HPF
RLC LPF
RLC HPF
RLC BPF
RLC BEF
SallenKey LPF
SallenKey HPF
3rd order SallenKeyLPF
3rd order SallenKeyHPF
Multiple feedback LPF
Multiple feedback HPF
Multiple feedback BPF
3rd order Multiple feedback LPF
3rd order Multiple feedback HPF
TwinT notch
CR 2nd order LPF,HPF,BPF
Active filter
Filter index

Calculate the transfer function for 3rd order SallenKey lowpass filter with R and C values
Calculate the R and C values for the SallenKey filter at a given frequency and damping ratio ζ
Vi→ 

→Vo 
※ 3rd order filters are usually made from combinations of 1st and 2nd order filters following the equivalent block diagram.
Equivalent block diagram:
Vi→  2πfc1
s+2πfc1  →  (2πfc2)^{2}
s^{2}+2ζ(2πfc2)s+(2πfc2)^{2}  →Vo 
Transfer function block diagram:


