Resonnant circuits in cascade.

[Robert]

Correct me if I'm wrong, but is it not possible to have one resonnant circuit excite a second resonnant circuit and have a substancial gain in power? So in essence have  a high energy generator with only a minimal power input, such as a microcircuit multivibrator acting as initial source.

  I saw a radio shack circuit using a reversed 6/120 transformer  through a diode to generate a high voltage, the frequency source was a 555 timer.

[IcyBlue]

Correct me if I'm wrong, but is it not possible to have one resonnant circuit excite a second resonnant circuit

cascading resonant circuits is something that is done since the first day of radio technics. It has the effect that the bandwidth of the filter network is reduced by every single stage and the gain of the network is increased. BUT

and have a substancial gain in power?

resonant circuits have absolutely nothing to do with gaining power. Gain of a filter network means either gain in voltage or current. You can not have both at the same time, because of the law of energy conservation the total power in the system (U*I*cos phi) must be constant.
Resonant circuits at best can only be a means of tapping energy. They can not do this on their own. Even if you have a negative differential resistance driven reactive circuit, you still have the positive static resistance of the circuit that is throwing away all energy you might have gained; bringing the cop again below one.

So in essence have? a high energy generator with only a minimal power input, such as a microcircuit multivibrator acting as initial source.

This is physically impossible. I suggest reading a good book about filter networks and RF design - then the fog is starting to lift

I saw a radio shack circuit using a reversed 6/120 transformer? through a diode to generate a high voltage, the frequency source was a 555 timer.

This is a simple step-up converter, also known as 'inverter'. Although they produce a high voltage, they don't produce power. The current that is available at the high voltage side is significantly lower than the current that must be fed in.

PS: reactive resonant circuits indeed do suck energy from their surrounding - this is how radio works. The best way to demonstrate this is with a dipmeter. It indeed is puzzling how a circuit that is not even connected to the dipmeter steals its energy and this is the way this device works. It displays the energy that has been stolen from it - indicating a resonant circuit in it's surrounding. But at the same time the 'parasitic' circuit comes alive by the stolen energy, it in turn radiates energy off.

[thrival]

icyblue:

I'm sorry but I must disagree with you in part. Any good online electronics tutorial will
tell you that power increases anywhere from 10 to 1,000X in a parallel resonant tank,
at the resonant frequency. V is what the source imposes while I increases by exponential
amounts, and those immense currents can even increase V as well.  At the same time
input impedance is at its highest, in other words we can barely squeeze any energy into
our oscillating tank. Now it's true that these oscillating currents are confined to the tank,
but a secondary coil loosely or otherwise coupled to the tank inductor will carry that power
over to itself. The primary-secondary relationship can be 1:1. This is not a filtering
application so you shouldn't compare it to that. This is exactly what tesla coils are and
do. A primary resonant tank coupled to a secondary resonant tank steps up POWER,
There is no V vs. I trade-off. This is the big and open 'secret' tesla knew. It's right there in
the textbooks but ignored, overlooked, unused, but for filters and fetching in signals.
These aren't the only application for which resonance can be applied however, as tesla
coils prove. A cascade of resonant stages can suck in enough energy to power starships.
I'll admit this can be an a embarrassing fact to admit if one has worked in the field for
years and still missed it. I remember the first day in tech college, basic electricity, our
instructor told us: "You can't get something for nothing." That is a lie, a misstatement
he learned from instructors before him. The fact is nature IS a free lunch. The same
way of bringing in a signal (via resonance) can amplify that signal without limit. And we
can generate any frequencies we choose artificially; we are not subject to some special
vibratory rate the cosmos decides to shower down at 3 am.

Given the fact and demonstrable proof of resonance, it sort of makes rotating wheels
like the testatika a bit passe. I mean the wheel isn't really the secret. Over-efficient
electrostatic motors are easy to build. The cascade diode employed is interesting and
another OU device, but resonance is where the real action is. The testatika is a wonderful
demonstration of several free energy principles while keeping those same principles
hidden; the principles of which however, are in the public domain.

[Elvis Oswald]

The amount of energy applied would oscillate around a tank circuit until was lost to resistance.  This is not multiplying power.

As far as resonance - a given cap and inductor making up a tank circuit would resonate at one natural frequency.  Meaning that if you have a var. cap. - you would tune it, and at a certain point reach the frequency that would be perfect to oscillate with min. loss.  Right?

Are you saying that a using the inductor as a primary to a secondary circuit would generate current in that secondary circuit without any additional loss on the tank circuit?

[Elvis Oswald]

After further investigation....   

What about series LC circuits??

In series inductive/capacitive circuits... When a state of resonance is reached (capacitive and inductive reactances equal), the two impedances cancel each other out and the total impedance drops to zero.
-and-
The total impedance of a series LC circuit approaches zero as the power supply frequency approaches resonance. 
-and-
Extremely high voltages can be formed across the individual components of series LC circuits at resonance, due to high current flows and substantial individual component impedances....

Thus... a series LC circuit using a 10uF cap and a 100mH induction coil will resonate at 159.155Hz.  If the incoming cycle of A/C is 159.155Hz - you can expect impedance across the LC circuit to drop to zero.
This would be a short circuit - right? Add a resistor of 1ohm and you would see a peak of 100 to 1000 volts from a 1v power supply.

Apply this to using an antenna that can receive 7.4Hz.  {or maybe any broadcast frequency} and wouldn't this set up multiply the power??
Wouldn't a secondary circuit have current induced in it?
Couldn't that current be altered to cycle at whatever rate you wanted??