Hi!
It seems (for me) I'm standing before impossible task... My task is to make a circuit for measuring wood moisture content. This means measuring resistance of moist wood (around 10kOhm) to realy dry wood (up to 5GOhm). I have to admit after high school (electronic) I drifted towards industrial automation so coming back to pure electronic is painful :)
I can use voltage up to 24V DC, my aim was using stabilized 10V. This gives me range from 2nA (5GOhm) to 1mA (10kOhm). Also the accuracy should be better at lower current and not so important at higher values.
Also the wood block is around 10 -12m away from the actual circuit - using silicone (or Teflon) cables, preferably non shielded.
So, in whole design my first task (and probably the most difficult one) is to make a sensing circuit. Has anybody some guidelines, maybe already sample design which could be modified?
Any help is greatly appreciated!
Thank you!