Trying to make a rain sensor measuring at 100k ohms (when wet), trip a circuit that must be below 2k ohms to trip. What component(s) can I put in there to make it work? Thanks!
could you provide a schematic of your trip circuit. This shouldn't be too hard, but just don't quite understand what you mean by the trip circuit has to be below 2K.
Try this circuit. I have successfully used one like this in similar situations. Here, R1 is the standard PCB rain switch, and changes the equivalent resistance of the transistor when wet. Any small, medium-to-high gain NPN transistor should work but if not, you could try a Darlington transistor. Be sure to observe correct polarity or it won't work.
Thanks! I'll try it.