Joule Thief

[Pirate88179]

@ all: I am trying to wind a secondary coil onto a ferrite toroid core as a pickup (8 windings, tried also 100)
My primary is bifilar wound like the normal joule thief (8 windings).
The joule thief circuit also DOES light up an LED,
but i get absolutely NO VOLTAGE on the secondary. I am using a core salvaged from a PC power supply. I tried a green and a yellow one.
I really have no idea why this would not work.Maybe these cores are no good, so no magnetism reaches the secondary?
Anyone has an idea what is wrong?
Thanks

Hello and welcome.

Those colored cores are powdered iron and not ferrite.  Maybe they work the same, maybe they don't, I really don't know, but, they are a totally different material.  Ferrite is a ceramic and the powdered iron is a metal.  Possibly someone here knows what difference this makes electronically?  I would guess it has to do with the saturation levels and values.

Welcome aboard.

Bill

[Mk1]

@ all: I am trying to wind a secondary coil onto a ferrite toroid core as a pickup (8 windings, tried also 100)
My primary is bifilar wound like the normal joule thief (8 windings).
The joule thief circuit also DOES light up an LED,
but i get absolutely NO VOLTAGE on the secondary. I am using a core salvaged from a PC power supply. I tried a green and a yellow one.
I really have no idea why this would not work.Maybe these cores are no good, so no magnetism reaches the secondary?
Anyone has an idea what is wrong?
Thanks

Hi, now that you got everything hooked up , remove the led for jt spot and put it on the pickup coil.And remember your meter will not show the power if not rectified.


@ist

I think in the jt there already is a constant dc on either wire , i did a 4 toroid mag amp jt and it works!
Its a 4 mk1 style /slayer double, with 8 pickup coil , i am finishing the positive feedback
will give more details soon. 4 time the one on page 125.

[xenomorphlabs]

Thanks for the quick replies.
Removing the LED and putting it in the pickup-circuit does not light it up, multimeter reading is 0.00 Volt
in that circuit. So it seems that these cores do not allow the magnetism to flow like in a real ferrite core.
Only explanation that i have until now. Gotta get hold of some real ferrite.
EDIT: MK1 !!! That is worth to check out what happens with a rectifier. Thanks for the hint will try it now.

EDIT2: Bridge Rectifier did not help, still 0.00 Volts, its gotta be the core.

[xee2]

I tried the neon JT with a different toroid and it required changing the base resistor to 500 ohms to light the neon.

[innovation_station]

Thanks for the quick replies.
Removing the LED and putting it in the pickup-circuit does not light it up, multimeter reading is 0.00 Volt
in that circuit. So it seems that these cores do not allow the magnetism to flow like in a real ferrite core.
Only explanation that i have until now. Gotta get hold of some real ferrite.
EDIT: MK1 !!! That is worth to check out what happens with a rectifier. Thanks for the hint will try it now.

EDIT2: Bridge Rectifier did not help, still 0.00 Volts, its gotta be the core.

if this is TRUE ....  YOU HAVE SOLVED MY 4 MAG AMP PROBLEM AS I USED YELLO CORES.....  HUMMMMM

thank you ...  i will have to re build it agin ...... 

sheesh    lol