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Re: [Amps] resonance

 To: "Amps" Re: [Amps] resonance "Jim Forsyth" Mon, 5 Jun 2006 07:08:06 -0700
 ```Needs more refinement! In a parallel tuned circuit containing resistance, Xl and Xc are not equal at the resonant frequency. ----- Original Message ----- From: "Bill Fuqua" To: "Amps" Sent: Monday, June 05, 2006 6:51 AM Subject: [Amps] resonance > 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. > > 73 > 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: aa4lr@arrl.net >>Quote: "Not within a thousand years will man ever fly!" >> -- Wilbur Wright, 1901 >> >>_______________________________________________ >>Amps mailing list >>Amps@contesting.com >>http://lists.contesting.com/mailman/listinfo/amps > > _______________________________________________ > Amps mailing list > Amps@contesting.com > http://lists.contesting.com/mailman/listinfo/amps > _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps ```