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phase angle and impedance of resonant circuits
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August 31st 05, 10:22 AM
Roy Lewallen
Posts: n/a
wrote:
Oops, one other thing I forgot to mention:
Q = XL / XR
The Eternal Squire
Two problems.
1. It's XL / R. There's no such thing as XR, in this context anyway.
2. Q = XL / R only when the R and L are in series. The Q of a parallel
R-L is R / XL.
You can remember those by using a little thought. The Q of an inductor
is highest if it has zero series resistance or if it has infinite shunt
resistance. Conversely, if you put a very large resistor in series with
an inductor, you won't be able to distinguish the circuit from just the
resistor. So the Q will be very low. In the parallel case, a low value
of resistor will make the inductor become insignificant, trashing the Q.
Good luck with your exam!
Roy Lewallen, W7EL
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