Joule Thief

[Mk1]

@all

New energy news ...

http://dvice.com/archives/2009/06/led-clock-munch.php

Mark

[jeanna]

@ jeanna

No. Not a spark. For AC a capacitor acts like a path for the energy to flow through. The stray capacitance is just the capacitance that is not actually a physical capacitor. When a neon or fluorescent tube is lit with one wire, the other connection is through the stray capacitance between the tube and the circuit wires.

Boy, that doesn't make any sense to me at all.

How would it do that in a wire? I understand how a cap can 'pass through' the ac, because in ac nothing is going down the wire. It just jiggles and it can jiggle inside the cap and push around whatever is outside of it, but how a wire would do that is hard to both picture and believe.

If the 'capacitance' jumps the wire and skips going through the inductor coil, I suspect there is a very tiny spark.
Tesla went into a lot lot lot of detail on how to avoid the sparks that were really small and would limit the effectiveness of the high frequency experiment. He recommended the gutta. You recommend the thick plastic wire. I was using the mag wire for this and probably should have used the kynar wire. I was being greedy and wanted more turns, but maybe I will try the kynar.

When Tesla describes the one wire arrangement of ac, he specifically says the connection is to the ground. (through the operator's body, a metal plate on the wall or just a wire to the ground.) 
He is saying it is not being made to the other side of the battery - or dc circuit ground.

Ah will this be another scrubbing happening on the insides of my brain?

hmm,
thank you,

jeanna

@MK1
the true bug light! 

[xee2]

@ jeanna

Boy, that doesn't make any sense to me at all.

Tesla used the ground as a return path because at large distances current flows much easier through the ground than between plates of a capacitor.

I think your idea of AC going back and forth is good. The stray capacitances act the same way. The only difference is that instead of being a component, the capacitor plates are just various parts of the wires.

A capacitor is just two conductive plates separated by a non-conductor. The stray capacitances are just parts of wires (conductors) separated by air (non-conductor). The idea is that in addition to the capacitors you add to the circuit there are a lot of invisible stray capacitance capacitors that you do not see. These have a very small capacitance and therefore do not allow much energy to pass at low frequencies and so are effectively not there at low frequencies. But at high frequencies even their small capacitances can conduct a significant amount of AC current.

[resonanceman]

Boy, that doesn't make any sense to me at all.

How would it do that in a wire? I understand how a cap can 'pass through' the ac, because in ac nothing is going down the wire. It just jiggles and it can jiggle inside the cap and push around whatever is outside of it, but how a wire would do that is hard to both picture and believe.

If the 'capacitance' jumps the wire and skips going through the inductor coil, I suspect there is a very tiny spark.
Tesla went into a lot lot lot of detail on how to avoid the sparks that were really small and would limit the effectiveness of the high frequency experiment. He recommended the gutta. You recommend the thick plastic wire. I was using the mag wire for this and probably should have used the kynar wire. I was being greedy and wanted more turns, but maybe I will try the kynar.

When Tesla describes the one wire arrangement of ac, he specifically says the connection is to the ground. (through the operator's body, a metal plate on the wall or just a wire to the ground.) 
He is saying it is not being made to the other side of the battery - or dc circuit ground.

Ah will this be another scrubbing happening on the insides of my brain?

hmm,
thank you,

jeanna

@MK1
the true bug light! 

Jeanna


Tesla  was  using alot higher voltages that we are using .
Also insulation  is alot better now than it was at his  time.



I think I might be able to help with  the capacitance  thing.
Keep in mind that  inductance and capacitance   are  2 sides  of the same  coin .
WHen  current  flows though  a wire  it sets up  a  field   around the wire ........  It is said to  be a magnetic field .......but I believe that is an oversimplification .

As  you know   especially  with  AC  inductance   what is  taught   is not  quite right.
The  field  around the wire interacts  with ALL things  around it ......some more than others .
A capacitor works in  a similar way .     The  current  flows into one plate of the cap and  induces a change in  the  other  plate  of that cap . 

The  capacitive   charge .......like the inductive charge  influences ALL things around it to some degree .     

It  was parasitic  capacitance  that  the original  question was about .
Parasitic  capacitance is when  other parts  of a circuit  start acting as if they  are plates   of a capacitor ..... ( such as the leads  of the LEDs )
As  the  frequency  increases   the  problems with  this kind  of  unintended   capacitance   grows  . 
     
Any  2 wires   have  some capacitance between them .....
It is possible that  even atoms have  capacitance between them


It takes  smaller and smaller capacitance   as the frequency or  voltage rise .
That is  why  parasitic  capacitance  is more of a problem  at high frequencys 
The  parts of a circuit   stay the same ...........but at high  voltage or high   frequency  they become capable  of  carrying enough charge to be noticeable


gary

[nueview]

this goes for the dipole moment of all elements and producing of a wave of great intensity and short length
there is a MIT lecture on you tube about dipole nature of elements and if you deminish the area fo tention the spark increases through a small tube confined space adds to flow.
Martin