thermistor low pass filter

Discussion in 'General Electronics Chat' started by Suseptor, Apr 17, 2012.

  1. Suseptor

    Thread Starter New Member

    Apr 6, 2012
    1
    0
    Hello,

    My question is about RC low pass filters. My signal will be a DC voltage from a thermistor, that I will buffer with an op amp and then A/D in a PIC. I want to filter all noise above DC. I could just use fc=1/(2piRC), pick fc=20-40 Hz, R=50K-100K, and find C. The noise that I know of is at 50-60 Hz, 500K Hz, and 2.4G Hz. How many additional smaller caps/fcs, at what intervals, are needed to filter out the higher noise frequencies?

    Thanks,
     
  2. pilko

    Active Member

    Dec 8, 2008
    213
    20
    You could use your pic to do the filtering.
    Instruct the pic to read the thermistor several times per sample and only accept the "sensible" readings.

    pilko
     
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