Joule Thief

[TheNOP]

one thing i want to point out about the words "good toroid" or "no good toroid".

When one coil is near another, a varying current in one will produce a varying magnetic field which cuts the turns of the other coil, inducing a current in it. This induced current is also varying, and will therefore induce another current in the first coil. This reaction between two couple circuits is called mutual inductance, and can be calculated and expressed in henrys.
The symbol for mutual inductance is M. Two circuits thus joined are said to be inductively coupled.
Tee magnitude of the mutual inductance depends on the shape and size of the two circuits, their positions and distances apart, and the permeability of the medium. The extent to which two inductors coupled is expressed by a relation known as coefficient of coupling (k). This is the ratio of the mutual inductance actually present at the maximum possible value.
Thus, when k is 1, the coils have the maximum degree of mutual induction.
The mutual inductance of two coils can be formulated in terms of the individual inductances and the coefficient of coupling with the formula: M = k square root(L1L2)

if the coupling coefficient is low, you will need more turns on the jt coils to compensate.
the coupling coefficient will also affect any pickup coil(s).
the jt coils turns # change will also affect the transformer ratio, to get a say voltage on a pickup coil will require more turns.

air core do work but not very well due to  the coefficient of coupling.

just to let you know, i get pretty good results with iron core toroids.

[Mk1]

one thing i want to point out about the words "good toroid" or "no good toroid".
if the coupling coefficient is low, you will need more turns on the jt coils to compensate.
the coupling coefficient will also affect any pickup coil(s).
the jt coils turns # change will also affect the transformer ratio, to get a say voltage on a pickup coil will require more turns.

air core do work but not very well due to  the coefficient of coupling.

just to let you know, i get pretty good results with iron core toroids.

Nicely said, thank you . I do like my toroid because the number of turns needed on the jt side are low , i like that because it leaves more room for pickup coil.

I can't wait for more info and pictures.

Mark



http://www.electronicsurplus.com/ccp75172-universal-toroid-core-829-0080-40156.htm

[Mk1]

@alll

Very interesting on dirty electricity making people sick, now that can only hurt, lol ya right it can't heal .

http://www.youtube.com/watch?v=WOwyn-xVXV4

One they tell you there is a electricity field , you can't see , hum sure the meter dose , if a meter dose it means we can tap that field!

How to put a spin on a story.

Mark

[jadaro2600]

Why does my toroid sing?

[Mk1]

@Jadaro

Coil sing most of the time , not always in audible range. loose coils don't help.