Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: Periodic motion vs. oscillation



How does this apply to electronic oscillators?

The std. method to release a pendulum w/o "a push" is by burning a fine
thread.

And in an LCR osc. the "natural" frequency is a function of the
damping; is this true for a pendulum?

bc

bc

Michael Edmiston wrote:

Robert Cohen's and Hugh Haskell's usage appears the same as mine. Hugh
also raises the valid point that the period of oscillation might not be
exactly constant. My simple pendulum example is one for which the
period is not constant unless the amplitude is constant.

When the restoring force is linearly dependent on the displacement, we
have simple harmonic motion and the period is not amplitude dependent.
Therefore, if the oscillation is damped, the period does not change as
the oscillation amplitude decays. On the other hand, if the restoring
force is not linear, such as in the simple pendulum, then the period is
amplitude dependent. In the case of a damped simple pendulum, as the
ocillation amplitude decays, the period become shorter. A
simple-pendulum clock will speed up as it unwinds if the escapement does
not maintain a constant amplitude as the spring unwinds.

In my usage I do not restrict that "oscillation" keep constant period.
I only restrict that osciallation requires a restoring force that brings
the object back through an equilibrium position at which point the
restoring force is zero. Other forces (such as friction) do not have to
be zero at the equilibrium position.

Michael D. Edmiston, Ph.D.
Professor of Physics and Chemistry
Bluffton College
Bluffton, OH 45817
(419)-358-3270
edmiston@bluffton.edu