One way to define the "Q" factor for a damped oscillator is by counting the number of cycles it takes for the amplitude to decay significantly. The general rule is
low Q system amplitude decays to 1/e in a few cycles high Q system amplitude decays to 1/e only after many cycles
That's certainly true.
One can make a more quantitative statement, as shown in the lecture on forced harmonic motion. Specifically,
From which one can derive an almost-simple way of calculating Q.
Unfortunately, in the review session just before Test 1, I got it wrong: I stated, and wrote on the board, that Q was equal to the number of cycles required to decay to (1/e) divided by π, instead of (1/e) multiplied by π.
Please accept my apologies. Before we move on, please take the time to check your notes, and, if necessary, to correct them.
Copyright © Michael Richmond.
This work is licensed under a Creative Commons License.