Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Wood sensor using opamp lm358

  1. Sep 2, 2016 #1
    i connected pin 4 and 8 to gnd and +5 v respectively
    .when pin 2 touches wood, or hand pin 1 is high.
    i understand skin is capacitive , but wood?
  2. jcsd
  3. Sep 2, 2016 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Your circuit is badly designed so the output has no meaning. What about pin 3?

    The output (pin 1) will be high if 1In- (pin 2) is lower than 1In+ (pin 3).

    Static electricity on your skin or the wood can easily make pin 2 higher or lower than pin 3.
  4. Sep 5, 2016 #3


    User Avatar
    Science Advisor
    Gold Member
    2017 Award

    quite an odd post
    How about posting about what you are actually trying to achieve with this op-amp :smile:

  5. Sep 5, 2016 #4


    User Avatar
    Science Advisor
    Gold Member
    2017 Award

    A circuit diagram helps everyone to understand what's being discussed. You can't expect every contributor to make a personal sketch.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted

Similar Threads - Wood sensor using Date
Third Order Intercept - Use Peaks or RMS? Thursday at 12:29 PM
Advice on Ultrasonic sensors? Oct 23, 2017
Viscocity sensor for grease levele measurment for gears Sep 25, 2017