Active Filter Applet by Joachim Köppen

Discussion in 'Electronics Resources' started by jbanneck, Jan 31, 2010.

  1. jbanneck

    Thread Starter New Member

    Sep 16, 2008
    I have tried to use the active filter applet by Joachim Köppen. When I used the suggested values to design a 2 pole Chebychev 1 dB ripple low pass filter the cut off frequency was 40Hz not 80Hz as expected. This was confirmed in 2 actual circuits. The values provided by the applet were:
    C1 and C2 = 100nf
    R1 = 44.13K
    R2 = 12.06K

    Does anyone have any experience with this applet?

    It is great as you can specify equal values of either the caps or resistors as well as the type and number of poles in the filter. I have not seen any other applet llike it on the net. To bad it does not seen to work. Any ideas?
  2. t_n_k

    AAC Fanatic!

    Mar 6, 2009
    Yes - seems to have a bug.

    I've tried TI's Filter Pro which works OK.
  3. bertus


    Apr 5, 2008
  4. jbanneck

    Thread Starter New Member

    Sep 16, 2008
    Thanks bertus and t_n_k, This is were got the link originally. None of the other links or the TI filter pro let me set the caps in the circuit.

    BTW Joachim Köppe applet does not seem to work for butterworth filters either. I looked for a blog or some way to contact Joachim Köppe about the program but was not successful.

    I did fudge the crossover frequency (120Hz) and though experimentation I did get a good x-over. My Yamaha HS80Ms now have a direct connection to powered sub-woofers!

    Thanks again,