The story of Q (pendulum, quartz, atomic clocks)

The letter Q, often called the quality factor, is used in discussions of clocks and oscillators. The concept of Q is applicable to any system which exhibits energy dissipation and periodic behavior. It is a measure of energy loss; actually, a self-timed measure of the rate of energy loss. Thus springs have Q ('vibrators'); pendulum clocks have Q (oscillators); atomic clocks have Q (resonators); planets have Q ('rotators').

For a general description of Q see the Wikipedia page:

Johnson Patent, with Q

Here is an image showing where, in the context of electronic resonance, Q was first used:

Reference documents

Here are primary documents that I have collected over time:

Letters in the Quarterly Journal of the Royal Astronomical Society, by Bertha Jeffrys, David McMullan, Peter Fellgett, Ken Smith:

Wikipedia pages related to Q

Other papers about Q

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