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man i'm having another Amateur EE Moment
in a nutshell: I have built a joystick adapter. I want to reduce the range of the pots in the joystick. Right now the pot is 0-120 kohms; I'd like that to become 0-90, say. Ideally.
I *cannot* modify the joystick. A series resistance won't help, obviously, but a parallel resistance seems like it should. I was thinking of putting a trimpot in parallel with the axes.
It's been a long long time since I calculated parallel resistances and I remember the results being unintuitive to me, but I'm still surprised by what I'm getting. Even a 2 megohm resistance in parallel with 120k knocks 10k off the maximum resistance. Really?
I'm using one of those javascript calculators. Is it wrong or does reality really work this way
I could put a megohm fixed resistor in parallel, with a switch, so I can toggle high range and low range, I guess.
sorry, I was unclear: the problem is not that I can't drop the total resistance enough, it's that I'd like to be able to turn the trimpot to max and get back to a total combined resistance of nearly 120k
obviously if I turn the trimpot down to zero it'll drop my combined resistance to nothing, that much is not in question. the problem is that i can't "go back to normal" by turning the pot all the way up even with a 2meg
WITH THAT SAID this is all moot because I had misdiagnosed the problem, which was really just that my joystick was very dirty when I thought I had cleaned it. So my whole theory of what was causing my problem was wrong and now i'm not trying to do this anymore.
