[Top] [All Lists]

[Amps] resonance

To: (Amps)
Subject: [Amps] resonance
From: Bill Fuqua <>
Date: Mon, 05 Jun 2006 09:51:26 -0400
List-post: <>
Maybe it is time to change the thread.
   Passive Resonance is a frequency selective means of storing oscillating 
energy. It occurs when energy oscillates back and forth between two 
complementary energy storage mechanisms. In the case of the pendulum you 
have kinetic and potential energy.   In a circuit the storage mechanisms 
are the inductance and capacitance. The inductance is the kinetic energy 
storage mechanism  and  the capacitance is the potential storage 
mechanism.  When there is a balance between these  Xc=Xl the circuit is at 
resonance. That is because all the energy from one goes to the other and 
back except for the bit that is lost in the resistance. A pure resistance 
alone is not resonant. That is the flaw in defining resonance as when Xc=Xl 
alone.  In a resistor zero does equal zero at all frequencies.
    Another property of resonance is that besides selectivity the energy 
stored in the system is greater than that passing to or from it when at 
equilibrium. And the Q is the amount of energy stored divided by the amount 
of energy going into the resonant system during each cycle. We usually see 
the other definitions regarding  reactance and resistance and bandwidth and 
resonant frequency. All three produce the same unit-less value.
    I use the term passive because some of the properties of passive 
resonance (not all) can be accomplished by active filters and by digital 
methods.  Even though a "flywheel" may store oscillating energy it is not 
frequency selective, thus not resonant. We often use the term "Flywheel 
Effect" but "Pendulum Effect" may be more accurate.

Bill wa4lav

At 10:45 PM 6/4/2006 -0400, Bill Coleman wrote:

>On Jun 4, 2006, at 8:23 AM, R L Measures wrote:
> > My dummy load is non-resonant, so that's a problem?
>Dummy loads are resonant by definition, since they provide a purely
>resistive impedance. (ie X = 0 is the definition of resonance)
>Bill Coleman, AA4LR, PP-ASEL        Mail:
>Quote: "Not within a thousand years will man ever fly!"
>              -- Wilbur Wright, 1901
>Amps mailing list

Amps mailing list

<Prev in Thread] Current Thread [Next in Thread>