OK, here is an example.

One of my TBF pancake coils measures 685 microHenry using my ProsKit inductance meter. When I disconnect the series connection and measure the two files for capacitance I get 2.75 nanoFarads. I have measured the resonant frequency in three different ways (single pulse ringdown, continuous pulsation ringing, and maximum voltage rise during frequency sweep) and get 242.7  kHz each way (within a few 100 Hz). Working the resonant frequency calculation backwards to solve for capacitance using the resonant frequency and the inductance, I get 0.628 nF (627.78 picoFarads) which actually seems more reasonable than the nearly 3 nF value.

The other TBF pancake coil measures 661 uH and the capacitance 2.19 nF. Resonant frequency is 273.2 kHz and solving the equation for capacitance I get 513.43 pF.

Both coils give huge voltage amplification on the resonant ringing. I pulse with a depleted 9V battery and get around 400 v p-p ringing oscillations.

The end of one winding,returns back to the center,and is connected to the beginning of the other winding.

I am using my DMM to measure the inductance value,and the leads are connected to the ends of the series coil pair.

The capacitance value was taken with the two windings disconnected from one another-as Mags asked.
Once the two windings are joined together(series connected),then would not that capacitance value change?,as no capacitor has there two plates joined together,as the bifilar coil dose.


Added
Ok,went and checked capacitance again.
Bifilar coil has .66nF capacitance,and get this, -(yes,minuse) 50uF when the two windings are hooked in series. So guess we cannot measure capacitance when they are linked together.
So what dose that do or say about our capacitance value when the coils are hooked in series,and we are carrying out tests based around the two windings open circuit capacitance value?.

Inductance still reads .06mH
If i join the two DMM leads together,i get .00--nothing.


Brad

Ah-hah! The first time you said 0.06 nH.... nanoHenry! So when we worked the equation or did the sim we got the 588 MHz frequency.

Now, with 0.06 mH, or 60 microHenry--- that's a lot more plausible and I believe that a DMM could measure that value, whereas 0.06 nH is not really believable.

So, working the equation again using your frequency (my rough estimate!) of 1.24 MHz from the ringdown, and 60 uH, I get a capacitance of 274.5 pF which is entirely plausible for your coil. (plus your probe of around 20 pF) Call it 250 or 255 pF.

Ok,so what would happen if the winding capacitance was increased?
Would our resonant frequency come down in value?

As capacitance and/or inductance goes up, resonant frequency goes down. Bigger buckets take longer to fill and empty.

Thought experiment.

If i pull apart say a 1uF cap,and made a transformer from the cap plates,instead of using copper wire--what would be the outcome of that transformer ?

Brad

I have no idea.


I think the capacitance meters are being fooled by the relatively large inductance of the coils when we measure them that way. I think the meters basically work by creating a LC tank circuit and measuring the resonant frequency of the LC tank, then calculating either inductance or capacitance based on that. SO if the "capacitor" has substantial inductance, the resonant frequency will be lower than expected and so the calculated capacitance value will be higher...and wrong.

This was a good read,if anyone is interested.


http://coefs.uncc.edu/mnoras/files/2013/03/Transformer-and-Inductor-Design-Handbook_Chapter_17.pdf


Brad

Preserved for posterity... and evidence.

In Texas we have a name for people who lie and misrepresent and insult others where they cannot respond. 

Don't think you can sneak this vile behaviour past me, Burgess. One day you will have to answer to a higher power.

@Tinselkoala,

You jokers like to fool around, then when you're pinned down on something you're really unknowledgeable about, you continue to act like you're joking to appear like "know-it-alls". Everyone can see you in your nakedness like the "Emperor with no clothes". Why don't you frauds try getting a life?

You can lead a horse to water,but some of them just need shooting-so as they do not consume valuable resources 

He seems to fit in well,over at EF 


Brad

@Tinman,

Maybe Texas will evolve it's own distinct dialect of English like the Australian version you DOSED up!

@Tinman,

Maybe Texas will evolve it's own distinct dialect of English like the Australian version you DOSED up!

Ah come on synchro--you guys put the steering wheel in the wrong side of the car.

"Coil for Electromagnets." means "Coil for Electro-Magnetizing."

 "The Lorentz force is the combination of electric and magnetic force on a point charge due to electromagnetic fields".

The U.S.A. has two North Korean Satellites passing over the country that can deliver an "Electro Magnetic Pulse" that has the deadly force to kill 90% of Americans from proximate consequences. This weapons technology is a direct descendent of "Tesla's Serial Bifilar Pancake Coil", persistently hidden from view by snake oil videos from this conceited agent of disinformation. Tinselkoala is just a "Cheap Carnival Huckster"! He has no right to be on Youtube.

Send a PM to Stephan Hartiberlin to help me throw this Bum out!

All insults removed from this post.