Peter Chadwick wrote:
>Rich said:
>> If an L-network was resonant on the operating frequency, infinite
>current would flow through it because the reactive components are
>equal, opposite, in series, and not in parallel.<
>Only because of your non-rigorous definition of resonance. AC theory
>tells us that the only definition of resonance that holds for all cases
>is that the applied voltage and current are in phase. The 'XL=XC'
>definition is a very loose approximation, and falls over badly when Q
>is low. There are occasions where it doesn't matter, but for an
>understanding of what is happening, it is necessary to appreciate the
>inherent errors in the approximation. The difference can be very
>important where feedback is applied, because a tuning error can lead to
>instability.
>Ian says that in practice, it doesn't matter. Not to the appliance
>operator, I suppose.
That wasn't the point I was making at all!
An L, Pi, Pi-L, T or similar network can be analysed, explained and
designed in complete detail without ever using the concept of
"resonance", so for these particular purposes the definition genuinely
does not matter.
--
73 from Ian GM3SEK
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