[sdiy] The Origins of Q

[Glen]

At 01:29 PM 3/27/2005 , nN AAt     e     e wrote:

>Historically the letter Q was an
>arbitrarily chosen symbol to designate the ratio of reactance to resistance
>of a circuit element. The name quality factor was introduced later
>
>http://roland.lerc.nasa.gov/~dglover/dictionary/q.html

Thanks, Nate.

So "Q" predates "quality factor", with regards to measuring the Q of an
inductor or capacitor. I had always thought that Q was an abbreviation for
the phrase, which would have implied the phrase would have came first.
Instead of Q being an abbreviation, it appears that "Quality Factor" is in
fact an extrapolation.  :)

I wonder if this also applies to the use of "Q" to describe the slope or
selectivity of a resonant circuit?

I suspect that was also an extrapolation, which came a bit later.


take care,
Glen