Hi Mike,
Thanks a lot ! your suggestion is very helpful!
I'm actually a Theoretical physics undergraduate, this is the first time i'm doing electronics , but my demonstrator didn't know how to do it either...
Our project is actually using a Op amp 741 but i couldn't find it in the LT spice. Your simulation looks really great and I have tried playing around the circuit.
My technician suggested me to add a inverting loop and also a capacitor for absorbing the frequencies to the circuit.
For the resistance of the soil against moisture I would expect to see an exponential decay of resistance as the soil gets saturated with water , is it right?
I'm not too sure what dead band or hysteresis means , but what i did to the circuit is by using a Blue LED with 3.5 V forward voltage, and Red LED with 2.7 V forward voltage
The transition between the light will be gone because the forward voltage is large in opposite direction. I don't see why we want to see the intermediate LIGHT , instead of just Yes and NO? I thought it's better to make only one of the light remain lit
Thanks for your help again!
Cheers!