Joule Thief - still not working....

[fungus]

On Aug 12, 8:16 pm, Jon Kirwan <j...@infinitefactors.org> wrote:

In that case... we should talk about that kind of schematic, shouldn't
we?  PICs and some other micros can operate off of 2V or so.  Call it
2 AA's, for something from 2.2V to 3.1V operation range.  If you
select a down-to-2V microcontroller, you can do the voltage boost
control AND the PWM intensity control as well as all the special
effects from a single IC and a handful of cheap external parts.

Ready for that?

I'm guessing it wouldn't be difficult but I'm
leaning towards switching LEDs in groups. If you
do it this way you'd need a separate transformer
for each group - could get messy.

Maybe for version 2.0 ...

 

[Tom Del Rosso]

John Larkin wrote:

That's a horrible circuit. Too many conflicting parameters depend on
the value of R1. A proper blocking oscillator uses an RC time constant
to set the rep rate, and a separate resistor to limit the base
current.

ftp://jjlarkin.lmi.net/BlockOsc.JPG

How can that oscillate without feedback? I mean, would this oscillate?


------------------------
|
|
|
R
R
R
R
|
|
|
|--------CCCCC------RRRRR------|
| |
| |
| -------
----- \ /
----- \ /
| \ /
| -------
| |
| |
| |
----------- -----------
------- -------
--- ---


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[fungus]

On Aug 24, 6:09 am, "Tom Del Rosso" <td...@att.net.invalid> wrote:

ftp://jjlarkin.lmi.net/BlockOsc.JPG

How can that oscillate without feedback?  I mean, would this oscillate?

No, but that has no inductor in it...

 

[Tom Del Rosso]

fungus wrote:

On Aug 24, 6:09 am, "Tom Del Rosso" <td...@att.net.invalid> wrote:

ftp://jjlarkin.lmi.net/BlockOsc.JPG

How can that oscillate without feedback? I mean, would this
oscillate?


No, but that has no inductor in it...

It does, but it's not very recognizable in ASCII. The C's are supposed to
represent a coil.


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