Joule Thief

[nievesoliveras]

Oh, I am sorry.

That is a shorthand for secondary. I can't remember where I learned that one, maybe math class, or maybe it is a biology symbol.

1^o= primary
2^o=secondary
||  = parallel

Thanks for asking, you were probably not the only one.

jeanna

Thank you @lady jeanna !

Jesus

[resonanceman]

I am looking  for  a source for  toroids   

Does anyone here have any experience  with  specifications  for  cores ?

Here is a spec sheet I found on the web

http://www.cmi-ferrite.com/Products/Materials/data/Summary%20Data%20Tables.pdf

All the  Mn Zn  ferrites   have pretty high initial permeability
The  Ni Zn ferrites  have much lower  initial  permeability
I  think that is probably important ;sense we  are using  very low power .

Also  because of low power I think  low  Coercive Force would be important 
http://en.wikipedia.org/wiki/Coercive_force

I am thinking that  C2050 might  be a good choice  for  normal JTs
CMD5005 might  be a good choice  if you are  going for some grunt .

Any  commments or advice ?


gary

[jadaro2600]

Continuing with my questions about the flux and flyback in general;

Does anyone think that, since the voltage builds across the coil when the transistor is turned off, then it couldn't be the induction in the coil to base that's cause it, and instead just the collapsing magnetic field..

I'm pretty sure that xee has pointed this out, then having said this;

1. There must also be a voltage collapse occurring in the coil to base as is occurring in the coil to collector?

2. Am I ( or am I not ) the only one that's operating the transistor in such a way as to completely turn the transistor on?  ...is there anyone that's NOT using it in this way...because not using it in this way would indeed result in transistor resistance, and thus, there may be less amp drawn from the battery?    ..and the result may be heat on the transistor?

[TheNOP]

@resonanceman
http://www.google.ca/search?hl=en&q=selecting+a+transformer+core&btnG=Search&meta=
http://www.mag-inc.com/pdf/twc-s2.pdf  page 5

1. There must also be a voltage collapse occurring in the coil to base as is occurring in the coil to collector?

depend on what you call "voltage collapse"
whatever is happening in the base coil, it is way much less then in the collector coil.
it is a need part for the oscilation, but not what give the voltage spikes.

2. Am I ( or am I not ) the only one that's operating the transistor in such a way as to completely turn the transistor on?  ...is there anyone that's NOT using it in this way...because not using it in this way would indeed result in transistor resistance, and thus, there may be less amp drawn from the battery?    ..and the result may be heat on the transistor?

turning the transistor on = shorting the battery poles.
the longer you short it, the faster you drain the battery.

do you have a scope ?

[xee2]

@ jadaro2600

The voltage is created by the collapsing magnetic field. It is a consequence of the collapse, not the cause.

Coupling between coils should be considered as a result of changing current flow, not voltage.