PWM - decay of value
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--- In basicstamps@yahoogroups.com, "Jon Williams" <jwilliams@p...> wrote:
> It depends on the load placed on the circuit. We recommend using an
> opamp buffer as shown on Tracy's web site.
I'm not sure I follow. The op-amp would be the end of the loop for
the Stamp output. the R and C in the signal line from the Stamp would
never see any load except the op-amp. no ?
A better quality cap will not have the leakage of an electrolytic. I
would think a polypropolene cap would offer much more stability of the
siganl than an electrolytic. Maybe I just need to do some testing.....
If the op-amp has some high enough impedance, then it theoretically
should not effect the incomming signal ?
One question is about if a pin is an input or an output. Does the
state of the pin effect the value ?
I'm not talking minutes, but if one has a few timing loops, it is
possible to not refresh the PWM value for longer timing periods.
again, maybe I just need to do some testing for my own pruposes. But,
I was hoping these things were known.
Dave
> It depends on the load placed on the circuit. We recommend using an
> opamp buffer as shown on Tracy's web site.
I'm not sure I follow. The op-amp would be the end of the loop for
the Stamp output. the R and C in the signal line from the Stamp would
never see any load except the op-amp. no ?
A better quality cap will not have the leakage of an electrolytic. I
would think a polypropolene cap would offer much more stability of the
siganl than an electrolytic. Maybe I just need to do some testing.....
If the op-amp has some high enough impedance, then it theoretically
should not effect the incomming signal ?
One question is about if a pin is an input or an output. Does the
state of the pin effect the value ?
I'm not talking minutes, but if one has a few timing loops, it is
possible to not refresh the PWM value for longer timing periods.
again, maybe I just need to do some testing for my own pruposes. But,
I was hoping these things were known.
Dave