There's this whole other stuff, the other 95 percent of the genome, that acts like rheostats — you slide this thing up and down, you get more or less of this protein. (scientificamerican.com)
An included rheostat light lets you adjust the brightness for a range of visibility conditions combined with the glo indicator pins to maintain accuracy. (geekwrapped.com)
If so, the gas pedal rheostat is probably telling the computer you are pressing it, causing the throttle to go up and in some cases not respond at all. (mechanics.stackexchange.com)