[Amps] Fwd: Pi-L In-circuit Adjustment Question

[G3rzp@aol.com]

In a message dated 20/02/2005 10:34:05 GMT Standard Time, r at somis.org  writes:

A  Pi-network is not resonant because it is two L-networks in series, 
and  L-networks never operate  at resonance.



This depends upon your definition of resonance. The only definition that is  
mathematically applicable to all tuned circuits is that the applied voltage 
and  current are in phase. Under these circumatances pi and L networks are  
resonant.
 
Any other definition give sproblems with analyis of circuits such as low  
level tuned amplifers, even oscillators, and phase discriminators such as the  
Foster Seeley. Using XL = XC is a convenient approximation, especially where the 
 Q is high, but is not strictly correct, and can easily lead to errors unless 
its  inherenty simplification is realised.
 
73
 
Peter G3RZP