Question

I need to obtain an approximate implementation of a Butterworth low pass first order filter using P-spice. It suppose to have a cutoff frequency of 1000Hz and the attenuation cutoff frequencies fixed at 3db.

Answer 1

Frequency for low pass Butterworth filter

                  f(Hz) = 1/2*Pi* R* C

                   let C= 1 nF

                calculate

                 1000 = 1/(2*3.14*R* 3X10^-9)

                    R = 100 K (for approximate 1000 HZ) as for these value we will get 995.223 /Hz

Attached circuit can be created on any spice software

(circuit implemeted on circuit Lab, Please correct capacitor value 1 nF)