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Re: 7.1Hz, how the heck did Tesla succeed?



Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx>

At 11:28 AM 7/18/2005, Tesla list wrote:
Original poster: "Antonio Carlos M. de Queiroz" <acmdq@xxxxxxxxxx>

Tesla list wrote:
Original poster: Ed Phillips <evp@xxxxxxxxxxx>
"Right; I was thinking about the hot resistor in the RLC circuit.  If
you
have an ideal LC resonantor with zero bandwidth and infinite Q, and then
you wiggle the capacitor plates to add some FM, the losses are still
zero
so the Q is still infinite.

This depends on how the capacitor changes. There is no loss if the capacitance changes instantaneously when the capacitor voltage is zero. If there is some charge in the capacitor, a decrease in the capacitance increases the energy. An increase in the capacitance decreases the energy. It's then possible to increase continuously the energy in the circuit by decreasing the capacitance at any moment and increasing the capacitance back at the zero crossings of the capacitor voltage. The opposite operation drains energy from the circuit. There is no resistor in this circuit. Energy goes in and out in the force required to move the capacitor plates against the electrostatic force between them. Something similar can be obtained with a time-varying inductor.

Isn't this basically how a Wimshurst machine (or a Van deGraaff, for that matter) works. Charge a capacitor when the plates are close together at low voltage, then put mechanical work in and separate the plates, raising the voltage (keeping charge constant).


Flux compression generators sort of do the same thing with inductors and putting in mechanical energy after setting up a current in the inductor.


Antonio Carlos M. de Queiroz