calculating the resistors, capacitor values for pole zero low pass filter

Discussion in 'General Electronics Chat' started by dumindu89, Jul 18, 2012.

  1. dumindu89

    Thread Starter Member

    Oct 28, 2010
    113
    0
    I need to calculate the resistors and capacitor values for a pole zero (low pass) filter. The cut off frequency is 70 kHz.

    Please help me do the calculations.
     
  2. nomurphy

    AAC Fanatic!

    Aug 8, 2005
    567
    12
    F = 1 / 2pi*R*C, therefore R = 1 / 2pi*F*C, or C = 1 / 2pi*R*F

    In the reasonable value range, one answer out of many is 22.6K and 100pF.
     
  3. crutschow

    Expert

    Mar 14, 2008
    13,003
    3,232
    That, of course, is for a single-pole filter which has the low rolloff rate of 6dB/octave.
     
  4. dumindu89

    Thread Starter Member

    Oct 28, 2010
    113
    0
    I am asking the calculations for a pole zero filter as shown in the following figure. There are two resistors instead of one. Then what would be the case in calculating the values?

    [​IMG]
     
  5. Jony130

    AAC Fanatic!

    Feb 17, 2009
    3,957
    1,097
    All you need to do is to find the transfer function
    [​IMG]
     
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