Joule Thief

[shylo]

Hi all I find this thread most amazing ,.......I've tried making a jt using salvaged parts no luck so far. Can you use a smaller cap to charge a bigger cap then another bigger cap,then pulse the coil on the core ,...kind of like a step up transformer ?.....sorry I know I'm totally lost.......shylo

[kb24]

@Kb24,
The more  cap's you add into your circuit the greater the current stored... you add all the values together. Make sure you connect them as Bill suggested all in parallel.
You may find that initially due to the total capacitance value they may take a while to charge up. The cap's impedance will be a lot lower so the JT's ability to provide an adequate charge may take a while to overcome (depends on you JT design) as the cap's take on charge the impedance will rise until they are fully charged. Final point... make sure you have polarities connected correctly i.e. all +++ together and all  - - - together.  regards Merv

I am talking supercaps here....like 10 F, 50F and now I am up to 650Farads.  These larger Farad sized caps made all of the difference for me as they took the pulses and spikes and stored them as usable energy.

Bill

Thanks to all the positive input.. Working on it now.. Bill, may i know how much ur EB battery input to JT to light up CFL? Curious to know..

Thanks

[kb24]

its kinda getting more confusing for me now.. 

My 24unit EB without JT can light up 5 LED
My 24unit EB with JT can only light up 1LED

But..

1unit EB without JT cannot light up 1LED
1unit EB with JT can light up 1LED

So its seem like my JT work only if voltage are low.. Perhaps like what have been suggested, adding caps might help.. Tried with one and few caps connected in parallel. It cant even light up but it did spark for a second after every 1minutes.

Perhaps caps size too small?

and from the figure, i circle the connection from 12turn toroid to base of caps. If i remove the caps, the led become much more brighter. If i connect it, it get much dimmer. Why?

I know everyone is getting repeating about using caps.. but adding few caps into my JT + 24unit EB, i stil cant light up 5 LED.. is it really if i get bigger caps like what Pirate88179 can solve it?

Really many thanks

[Mk1]

@kb24

I am jumping in so , sorry if it was said before .

First is the jt working if you connect it to a regular battery ? If not one wire is either connect backwards or not wound in the correct spin , regardless reversing the connection of one of the wire should do . If you still have a problem i would look at the transistor is it a PNP or NPN , the battery could be connected the wrong way too because not all transistor are alike , BTW what are you using ?

I will be waiting for more info to help further .

Mark

[kb24]

@kb24

I am jumping in so , sorry if it was said before .

First is the jt working if you connect it to a regular battery ? If not one wire is either connect backwards or not wound in the correct spin , regardless reversing the connection of one of the wire should do . If you still have a problem i would look at the transistor is it a PNP or NPN , the battery could be connected the wrong way too because not all transistor are alike , BTW what are you using ?

I will be waiting for more info to help further .

Mark

Thanks Mark. Yeah my JT work perfectly with normal AA battery. Can light up 5led with single AA battery. Right now, i am working earth battery with joule thief. My earth battery(EB) consist of 24units of cell in series. If i take 1 unit cells of EB, connect with JT, i can directly light up 1LED. But if i take 24units of EB with JT, i couldnt light up the 5LED. I just found out that as the moment my primarily winding at toroid touch the base of transistor, LED actually spark up in high intensity then gone.