At 07:08 PM 10/4/2009, you wrote: > >> >> He propopsed an idea that an impedance calculated > >> >> as (R1*R2)/(R1+R2) would reflect the "speed" of the signal - > >> >> the lower impedance - the higher speed. > >> > > >> > Yes. > >> > > >> >> I objected it with the example to remove the bottom > >> >> resistor, - the impedance will be higher, and the speed > >> >> will be higher. That's it, nothing more, no rules changed. > >> > > >> > Yes they have. The output will now go to 5V instead of 3.3V, > >> > which is a violation of the rule that the output must drive > >> > a 3.3V input within its spec. > >> > >>Well, the idea is scalable as one might expect. Decrease divider's > >>bottom resistor R2 by 0.1% (to stay within specs). You'll get lower > >>impedance according to your (R1*R2)/(R1+R2). > >>Is not it obvious that despite the fact that impedance gets lower, the > >>speed of rising will be lower, not greater as you stated above? > > > > Does the number 1-1/e mean anything to you? > >Why are you asking that? To evaluate your background knowledge. >Best regards, Spehro Pefhany --"it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist