Marechiare wrote:
> How will be the time to rise the signal on the capacitor from 0V to
> 80% of 3.0V (that is 2.4V) in the case of 2.95K bottom resistor
> compared to the rise time when the bottom resistor is 3.0K?

Once again you are asking for the rise time to a fixed voltage, not a fixed
fraction of the steady state voltage.

Your problem statement was a 5V source driving a 2.000Kohm,3.000Kohm divider
with a capacitive load.  That means the steady state output is 3.000V.  If
we are measuring the rise time to 80%, then the threshold in that case is
2.400V.

If you change the bottom resistor to 2.950Kohms, then the steady state
voltage becomes 2.980V and the 80% threshold level therefore becomes 2.384V.
And yes, in the second case the result of a step input will reach the 80%
threshold (2.384V) a little quicker than it will reach the 80% threshold
(2.400V) in the first case.


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