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Resonance WFC measurements

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webmug:
Here goes resonance WFC measurements "3-23 VIC"

--- Quote from: Dynodon on December 01, 2010, 00:09:15 am ---I have a B&K LCR meter,and have measured it with that.But have no idea on how to use a scope.My scope has stopped working,but I might have found the problem.It has been a hit and miss on working ever since I bought it.My cell measures @ 50uF with city tap water.Thats for a 3 inch long,3/4 inch outside tube with .090" gap,and the center tube is a little longer.
Don

--- End quote ---
edit:
Dynodon
Length 3 inch = 76.2 millimeters
Outside tube (3/4) inch = 19.05 millimeters
Gap 0.090 inch = 2.28600 millimeters
Capacitance @ 50uF with city tap water


--- Quote from: Donaldwfc on December 01, 2010, 00:26:58 am ---my meter is a VC6243

I get 130 uF with rain water, measuring just one tube on my tubular array, 0.0625 gap

i'm just wondering what kind of inductance to look for, to target 10,000 hz resonance

--- End quote ---

edit:
Donaldwfc
Gap 0.0625 inch = 1.5875 millimeters
Capacitance @ 130uF with rain water
measured the cell without water, so just air, and it is 25 picoF
also, calculated with air, it is 25 picoF

"By using an appropriate differential amplifier, probe, or isolator, accurate two-point oscilloscope measurements can be made without introducing ground loops or otherwise corrupting the measurement, upsetting the device-under-test, or exposing the user to shock hazard."

When we are going to measure at the wfc cell we are introducing ground loops and corrupting the measurement.
How do we measure at the wfc? ...Differential probe...

br,
Webmug

sebosfato:
webmug,


to measure static electricity you need a connectionless probe electrometer analog or digital. So you can see what is the voltage inside the water... It works by feeling the force of the electric field therefore it don't upset the device like you said...


However to feel see the resonance a simple 1000:1 probe can be the solution, or only a simple feedback coil witch you know the number of turns in relation to the inductor resonating so you can see the induced voltage therefore know what is the voltage level of the resonance.


the resonance feedback stan used only converted the frequency to square wave pulses.. so you could not get the voltage from there...

webmug:
I've been busy with my VIC and have not been able to get my coils into resonance with my wfc cell.

Coils I have on the UU-core:
Prim. 600wnd 13.62mH 11.6ohms
Sec. 2000wnd 137.9mH 44.9ohms
Choke1. 2000wnd 135.4mH 46.1ohms
Choke2. 2000wnd 138.6mH 46.5ohms
WFC cell: air=40pF water=1.23mF

I could find resonance with a 1nF 10kV cap (measured 942.2pF) between the chokes as replacement for the wfc cell and
measured this at probe1 to cap NEG and probe2 to cap POS (probe GND not connected to VIC circuit)
We can see a AC voltage swing signal almost equal and opposite voltages at the 1nF capacitor.

How is it possible to get resonance with 1.23mF WFC cell connected and measure 1-2kV?

@Dynodon,outlawstc
Do you have a reading of your WFC cell capacitance?

br,
Webmug

Dynodon:
Webmug,
My cell with tap water measures @ 100uF
Primary coil @ 240 mH
Secondary coil @ 3.8 H
Chokes were @ 8 H
Resonance was in the 30khz range.
 
Your voltage is @ 200v peak to peak
The capacitance of your chokes effect the resonance frequency too.
Your resonance for your cell may be over 20khz.What are you using for a frequency generator,and how high will it go?
Don

webmug:

--- Quote from: Dynodon on March 10, 2011, 00:38:33 am ---Webmug,
My cell with tap water measures @ 100uF
Primary coil @ 240 mH
Secondary coil @ 3.8 H
Chokes were @ 8 H
Resonance was in the 30khz range.
 
Your voltage is @ 200v peak to peak
The capacitance of your chokes effect the resonance frequency too.
Your resonance for your cell may be over 20khz.What are you using for a frequency generator,and how high will it go?
Don

--- End quote ---
Thanks Dynodon!

Ok, new test of my VIC. I have my PLL operating in VCO PULSE mode. (1..100kHz range)
As you can see I have now found resonance at higher frequency @32kHz. Measured with scope connected probe1 and gnd between chokes.
Got voltage AC swing of @1.3kV. (DC 12Volts input) I use a RHRP1560 - Schottky Diode

When you said about the coils having capacitance and effects resonance,
the total capacitance Ct=(CpSec + CpChoke1 + CpChoke2 +Cwfc) is close to the smallest capacitance in the total series circuit?
This Ct and the Lt is the resonance frequency the VIC will resonate? Should Cp be in the nano or pico farad?

When I connect my wfc cell I got resonance @63kHz @99Volts (scope probe1 without gnd to one side of the wfc cell) Gnd is pulling voltage down.
Should I make my WFC cell 2.0mm gap smaller or wider? Your cell is much smaller in capacitance than my cell (1.23mF)

Yes I now, a lot of questions... :-X

br,
Webmug

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