Joule Thief

[IotaYodi]

My question about the ignition coil was about how IT is wound and why it would be wound like that

An ignition coil is a transformer. A primary and secondary is needed in order to produce the high voltage,about 20kv,to fire the spark plugs. The collapse of the secondary magnetic field induces the high voltage. This is on the old mechanical type. The new electronic types I dont know.

[xee2]

@ altrez

Yes that is true but how do you hook it up? What wire from the JT do you connect to the + on the IC and what wire do you connect to the - On the ignition coil? And why do you need the Toroid? Cant you just use the 2n3055?

I am really lost on the wiring? Do you splice wires from the connections on the 2n3055?

Thanks!

-Altrez

Make a JT and then insert the IC between the collector coil and the positive terminal of battery. You can use an ohm meter to see which way the ignition coil + and - termninals should go. I have not done this. You will need to do some experimenting. I am just trying to help.

[Mk1]

@all

Those are the two spot where a would try a ignition coil jt .

And obviously only the coil use both coil like the jt output at regular jt led spot , but i fear blowing the transistor .

[xee2]

@ altrez

I am really lost on the wiring? Do you splice wires from the connections on the 2n3055?

Maybe a pictorial will help.

[jeanna]

xee2,
I am asking about blowing things because of this post from Stephan yesterday.

http://www.overunity.com/index.php?topic=7679.msg194259#msg194259
In it he says to jesus who has just lost a power device, which is really too bad,

Hi Jesus,
if you switch a coil via a transistor ... or other
electronic component you have to take care about the
BackEMF voltage of the coil,
when the transistor ... is switching off the circuit.

So you need a ...or a cap in parallel with the
coil, otherwise it will kill your electronic switch.

Better use a cap in this circuit and use a transistor ... that can stand the high ringing voltage from the BACKEMF....

So, I thought we are not having the kind of trouble Stephan speaks of because when you only use the secondary the feedback and spikes going directly to the transistor are filtered away.
However, if it is wired into the bjt circuit as you propose, I think it will produce a melt down. And, I would only try it with the 10T/60T you suggested. not the ig coil.

I have some I could try. I need to cool down first before I melt down...my hands are sticking to the keyboard.

jeanna