sabato 14 gennaio 2012

12 db low pass lep filter

Simple 12 db low pass filter.
This filter use 2 BC547 NPN transistor and a stereo 100k pot
 for the cutoff, instead of the pot. it's possible to use 2 photo resistor.
This filter is calibrated for 5v use but also 9\12 volt for simple application.
I've develop it with Peppo at LEP lab. in Milano.
I use it in this 6 bit noise generator, video.
Val Pastel made this filter audio test listen

A small revision for the 12 db filter, this schematics is calibrated for 12 volt use.
Here an High Pass version of the same filter.

1 commento:

  1. Hi Tony,
    I'm christian from italy.
    I've built your low and high pass filters and they works very fine. I would like to point out to you that, however, there is a small error in the high pass filter scheme: a polarization resistance on the last transistor is missing.
    I momentarily added a 1M resistor and the filter works. Let me know if another resistor value is better.
    Good work!