Directly proportional implies a relationship of the form y = c * x where c is a constant and * is multiplication. So it is linear.
To call an exponential relationship "directly proportional" would be wrong. On Tue, Jan 17, 2017 at 1:17 AM, Charles Steinmetz <csteinm...@yandex.com> wrote: > Tom wrote: > > That article has a major error. Anyone know what it is? >> > > Well, the author says the reverse current of a diode is "directly" > proportional to temperature. This could suggest that he means the > relationship is linear (the relationship is actually exponential with > absolute temperature). But that's not really an *error* -- just sloppy. > "Direct" does not necessarily imply "linear." An exponential relationship > is "direct" in the sense that it is what mathematicians call "injective" > (every temperature corresponds to exactly one value of reverse current). > > Then, in discussing the LM95235, he says that it can use the > "collector-emitter junction diode" of a transistor as the sense element. > Of course, a bipolar transistor has no collector-emitter junction. His > diagram correctly shows a diode-connected NPN operating in the active > region (forward biased, not reverse biased as the rest of his article > discusses) as the sensor for the LM95235. > > Are any of these what you had in mind, or is there more? > > Charles > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/m > ailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.