Magazine -4-
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Q, Quality factor Q is the energy that is stored in a pendulum divided by the energy that is dissipated during every period of oscillation:
Its maximization is an important prerequisite for the
construction of an accurate clock. In a typical pendulum clock, It can
be obtained using a high mass bob (great stored energy) aerodynamically
shaped (low air resistance and consequently small lost energy per period
of oscillation). This picture shows the value of Q for the Littlemore clock, the most accurate mechanical clock all over the world, when air pressure changes.
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It can be observed that Q increases in a relatively slow manner between the atmospheric pressure value (extreme right of the graph) up to about 0.1 mb. Between 0.1 and 0.01 mb, Q increases much more rapidly when pressure diminishes; the value of Q at a pressure of 1x10 -6 mb is about 1,500,000. The Shortt SH48, another famous precision clock, was kept running at about 40 mb, where it had its maximum Q of about 110,000. For a quick comparison, the value of Q for mechanical wristwatches varies between 100 and 300. For quartz watches, between 100,000 and 1,000,000.
There is a rich literature about this topic. You can ask for other sources.
