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photoresistor and POT command — Parallax Forums

photoresistor and POT command

wolffwolff Posts: 43
edited 2013-04-11 14:00 in Accessories
I'm trying to read light levels using a photoresistor and POT command (p-resister in series with .1uF cap) I get rather strange results. This is probably because the p-resistor range is way greater then the recommended 5-50K range.
Can anyone show me an easy way to constrain the resistance range of the photoresistor?
THANKS ALL!

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2013-04-05 07:56
    You can put a fixed resistor in parallel with the photoresistor and that will reduce the overall resistance range. You might make up a spreadsheet to see what the effects of different resistor values would have

    R = 1 / ((1 / R1) + (1 / R2))
  • ercoerco Posts: 20,261
    edited 2013-04-11 14:00
    You can also decrease your capacitor value somewhat to compensate for a higher resistance range.
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