In reply to RC Macaulay's message of Mon, 18 Dec 2006 20:17:29 -0600: Hi Richard, [snip] >BlankRobin wrote.. > >You may not need such a heavy duty spark generator. Instead of trying to >generate sparks at the requisite frequency, whatever you think it is, why not >just adjust the resonance of the tank circuit to match it instead? IOW, let >each >spark generate lots of high frequency oscillations? Just as in old spark gap >radio transmitters. > > >Howdy Robin, > >Thanks for the thought. Please expand on it. You have a picture in your mind I >am not seeing clearly but it is a very important idea that I must consider. > >Richard >
When a spark gap is incorporated in an LC tank circuit, and the capacitor is fed with DC current, it charges up until the voltage reaches the point at which the spark gap breaks down and a plasma forms. Once this happens, the plasma acts as a short, and completes the connection between L and C, thereby allowing an oscillating current to flow back and forth at a frequency determined by the values chosen for L and C. This continues until the energy stored in the cap. is finally lost in the resistance of the circuit, or in old radio transmitters, transmitted via the antenna. The frequency can be anything up to high radio frequencies, and can be changed by making either or both of L and C variable. Since you plan on using a fixed coil inside the tank, I would suggest a variable capacitor external to the tank. Then you can use the variable cap to search for useful "resonant frequencies" - if there are any. You could also include a switchable bank of capacitors with your variable cap to increase the range of frequencies that you can traverse. With this sort of setup, you only need to generate a spark often enough to compensate for the energy lost in the circuit resistance, rather than at the top frequency you want to test. That puts a much lower strain on your spark generator, so that a simpler, cheaper unit can be used. Each spark then results in a damped oscillation across the spark gap. If you monitor the oscillation on a scope, you can also play with the timing between sparks by varying the power feed, not to mention keeping an eye out for anomalous wave forms which could hint at special properties of the water. (A real time Fourier analyzer might come in handy too). Regards, Robin van Spaandonk http://users.bigpond.net.au/rvanspaa/ Competition provides the motivation, Cooperation provides the means.
