Joule Thief

[xee2]

@ jeanna

So xee2, is it this?

Yes. But, current is theoretically 25 amps max since the zenered voltage is 100 volts and the resistance of bulb and SCR is about 4 ohms. I=E/R

[jeanna]

Hi gadget,
It doesn't say on this package afaik.

It is GE yellow at the top and blue at the bottom of the package.
I agree, it would probably say if it were warm.

But it is a warm color, when you are accustomed to superbrights.

@all,
I have spent some time with that magnetics catalogue.
They have 3 size candidates that I want to check out in 3 different permeabilities.... just cuz.

1 1/2" and 2 1/2" and the one we have 3 1/3"

I am thinking this might be able to go smaller and therefore be a nice light unit with just the right amount of volts.
It might help with the squeal too.
If it is smaller it should have a higher frequency just naturally and in my mind this will allow a lower permeability to do the same thing... (or maybe I have it backwards) but there is only one way to know.

I am seeing the saturation like the capacitance.

A too small cap does nothing. It is always open and you do not even see it.
A too big cap and the thing takes too long to fill up and slows the frequency.

the saturation that happens too fast seems like the currents would just go through too fast and no real advantage comes about.
A too slow saturation low permeability and it won't even move .

So, I want to try 3 sizes in 3 permeabilities.

Any ideas?

jeanna

thanks xee2, I fixed it.

[crowclaw]

@ Jeanna,
Forgive me if this idea has already been looked at and I've missed it.
The basic JT circuit primary winding produces  nice negative pulses as does the secondary of course to turn off the base. Now using this winding to feed it's pulse output into the cathode of a diode, and likewise feeding the secondary winding pulses at the collector into the anode of a separate diode, then using a .001uf capacitor to smooth out the pulses connected across the open ends of the diode pair which are now floating and not grounded to the rest of the circuit, the result will be an increased DC output! If the primary and secondary bif windings are an equal number of turns, the output unloaded will be almost doubled!! Sorry if it's already been tried otherwise may be worth experimenting with?

 

[jeanna]

@Crowclaw,
You know what I always say don't you?
There is only one way to know.

,
jeanna

[gravityblock]

This may be the reason for not achieving the maximum voltage.  Heinrich Barkhausen discovered that a slow, smooth increase of a magnetic field applied to a piece of ferromagnetic material, such as iron, causes it to become magnetized, not continuously but in minute steps.  These magnetization jumps are interpreted as discrete changes in the size or rotation of ferromagnetic domains.

A coil of wire wound on the ferromagnetic material can demonstrate the sudden, discontinuous jumps in magnetization. The sudden transitions in the magnetization of the material produce current pulses in the coil.

The Wiegand effect is a macroscopic extension of the Barkhausen effect as the special treatment of the Wiegand wire causes the wire to act macroscopically as a single large magnetic domain.  The small high-coercivity domains in the Wiegand wire outer shell switch in an avalanche, generating the Wiegand effect's rapid magnetic field change.

Because the voltage induced by a changing magnetic field is proportional to the rate of change of the field, a Wiegand-wire core can increase the output voltage by several orders of magnitude as compared to a similar coil with a non-Wiegand core.

http://en.wikipedia.org/wiki/Wiegand_effect
http://en.wikipedia.org/wiki/Barkhausen_effect


GB