Alright Zad, I have some clarifications on the question. I want to KNOW what the power I am getting is. (It is NOT exponential because of the 2nd law of thermo.) The idea behind using the voltage multiplier is that the AC should pass through the capacitors without a wasteful diode voltage drop and should hopefully switch the diodes on without as much loss. (If you want, I can show with real world measurements why I'm convinced a x8 multiplier is best. That was about 20 revisions ago!

) I am unaware of the voltage source supplying infinite current, so that may be a solution to my problem. After inserting a current limiting resistor, I should find out in about 18 hours! But I seriously doubt that is the problem because of all the real world measurements I've taken. But it still is to be seen what the result is. In the time since I posted about 4 hrs or so ago, I've placed the results of the simulated experiment into a spreadsheet. (which I most regretfully do not know how to upload and link to...

If you want I'll email to anyone interested in seeing it!) On the simulation, notice that the voltage source is set to one volt. I couldn't find a nominal figure to work with when considering noise (which is what I'd like to harness. It's no fun just stealing from AM stations. I made sure my antenna length was in the IF, where there shouldn't be transmissions.) I just settled with 1V to see if I still get an exponential curve.

Here are the results of the real world measurements I took (forgive me, not enough time to use the table command, it's REALLY time consuming to use...):

# in Series Max Voltage Avg Current Watts

1 5*10^-3 1.1*10^-6 5.5*10^-9

2 10.6*10^-3 .6*10^-6 1.2*10^-8

3 104*10^-3 1.3*10^-6 1.4*10^-7

4 200.1*10^-3 1.7*10^-6 3.4*10^-7

Excluding the anomolous 2nd current data point, the fit is perfectly quadratic. The regression yields:

4.97E-8x^2 - 1.36E-7X + 8.97E-8

with an R^2 of .999

This was the results from my opamp amplified current (because I can't measure uA with my meter. Dave's uA was the inspiration for my design, so I think it's pretty solid... if not, the systematic error should have canceled as I built confidence in my measurements. just something to think about...)

Then, this afternoon, I measured using dBm (thanks Dave for showing me that too!) and I got:

-44.7dBm

-44.4dBm

-39.7dBm

-36.2dBm

and converting that to milliwatts, you get an equation very similar to the last with an R^2 of .990. And to try and get rid of meter flucuations, I measured the noise. I had zero noise as I added more wire between the probes.

That's another good installment of information. I assure you that this has been MOST frustrating to me. I've spent weeks reading the Art of Electronics and watching Dave's videos, and other forms of reference trying to figure it out. I've asked numerous forums and engineers, so it's down to you guys! Thank you for responding quickly as well! I REALLY appreciate it because my deadline is March 29th.

edit:

I thought I should share my graphs, so you guys don't have to sit and look at numbers....

image hosting jpgFrom that, I plotted the return of power versus cost and determined that x8 was the best because it cost the least per measured watt.

Because OpenOffice refuses to plot TINY numbers, I can't show the spreadsheet plots as more are added in series. But they all look very similar to the screenie of the last post except the amplitude...

Double EDIT:

I stopped the simulation in the middle of the run because the pattern was clear. (BTW, I am SO glad I know about RC time constants and didn't waste my time in the uS anymore!) So here it is:

image hosting pngThe power was SIGNIFICANTLY reduced... but the numbers do not even begin to explain why my real measurements are what they are. I was measuring millivolts at microamps, not millivolts at picoamps. Clearly my current limiting resistor is off. Anyway though, it isn't working right still on account that my voltage is set way high on purpose, but I'm getting less out than I would expect based on real measurements. So if I DID do the simulation correctly, can anybody explain my REAL results because they don't add up and they consistently don't add up?

p.s. Sorry about the mega long post and the double edit. Plz plz plz reply!