Joule Thief

[TheNOP]

Thanks   TheNOP

I am going to studdy the darlington  circuit  and  see what I come up with .


At first  the   narrow  voltage range  seemed like  a problem . 

Honesty I  don't know   where I am  going  with this circuit .
My  knowledge of electronics is pretty limited.

I am following  my intuition   with this.
My intuition  related to  electronics is  kind  of new to me.
I  am much better at  translating my intuition when it comes to mechanical  things .

I  am not  sure how to wire it ..........but is it possible  to  use a string of  diodes  that  have a voltage  drop  that adds up to 4 V?
I think a way to explain it  is the  connected   across the  diode  string .       The  voltage of the source and drain    would  float in relation to  the  gate  and  diode string .

On  the  darlington circuit it might  work to  remove the  1N4007 diode and the 10 K resistor .   
A  diode string  would be  placed  from  where  the 10 K  resistor was  to the bottom  line   on the  drawing    ( from gate to source ? )



gary

adding a one or 2 diodes before the gate might help(.707 volt drop for each).
but changing the resistor(10k) value should adjust the voltage at the fet gate, if needed.

the 1N4007 diode and the 100 pf capacitor are only needed to get a reading on you voltmeter.
i suggest using a bridge + capacitor instead to get a more accurate reading.




@all
I am asking myself questions about possibilities of rising current consumption.

at school they teach us lengthy on how to get ride of in rush current, bemf, hemf and switching bounce effects.
but not how we could harness them.

from the watts reading i get in a basic jt, i think the fets gate should withstand the spikes, but...
what if we get the hemf really bigger ?


there is two ways i can think of to block the spikes: surge suppressor and zener diode.
those two ways are almost always a waist in energy.
hooking either between the fet gate, or the first transistor collector, and the minus side of the battery might still get the jt running.


i am currently trying different design with a mix of simple inductor + toroid with matched and unmatched turns.
i will post if i find something interesting.

first thing so far is that the first inductance, the one that connect to the base, capacitance change with the number of turn.
in the capacitor to the base schematic, the capacitor is not really needed to adjust the circuit current.

[electricme]

@ Timmy1729
I don't know if anyone replied to your P207 cry for understanding of capacitors.
Join the club mate, these things are confusing to any newbie, but I will try to explain one type.

The Electrolytic

These capacitors are polaritory sensitive, there will be a Positave and a Negative connection
The majoritory have 2 wires coming out of the bottom of the cap.

OLDER electros were called Axiel caps, these have a single wire coming out of either end, the Neg is marked such.
These are horizontally mounted.

On the outside of the Vertical mounted cap,  will be an indicator of some kind to show you which wire is the Negative one.
This is generally a vertical different colour stripe with a row of ----- going from top to bottom, the wire closest to this indicator is the Negative.


Don't connect capacitors (electros) around the wrong way, they might go boooom.

If you have a cap, the voltage is marked on its side, if it shows 16v that means 16v DC is the limit for that cap
If you connect this cap to 24v it will try to peg the voltage back to 16v but it will begin to get hot and it will fail.

If you see a capacitor (electro) that is leaking white or brown stuff, that cap has been stressed, toss it away
If you see a capacitor              that the top is bulging, that cap has been stressed, toss it away.

The uF or pF is the amount of electrical energy the capacitor can hold.
A uF cap can hold a lot more than a pF cap

Theres a whole lot more about caps, but take it from me, you only need to know about the above ones for the time being, better not confuse anyone with too much detail.
 

hope that helped yo timmy

jim

[Pirate88179]

Thanks to everyone that has expressed concern about my cat.  I live alone and she has been my roommate for a little over 15 years.  She is hanging in there at this time but I have been in constant contact with the vet since I took her in yesterday for tests. She is home with me and I am trying to take care of her.

I have not had the time to read all of the posts on this, our fast moving topic.  I popped in a time or two but I am very behind.  Everyone keep up the great work being done here and I will join you as soon as I can.  Thank you.

Bill

[b0rg13]

Thanks to everyone that has expressed concern about my cat.  I live alone and she has been my roommate for a little over 15 years.  She is hanging in there at this time but I have been in constant contact with the vet since I took her in yesterday for tests. She is home with me and I am trying to take care of her.

I have not had the time to read all of the posts on this, our fast moving topic.  I popped in a time or two but I am very behind.  Everyone keep up the great work being done here and I will join you as soon as I can.  Thank you.

Bill

good luck and i wish you the best with your cat Bill.

[timmy1729]

@Xee, Jim
Thanks for the explanations!

So far, I've gotten 5 transformers, the two 200v 560uF caps, many other caps, an MJE13007A transistor, one small toroid, and two bridges off of the boards. I found another Schottky diode on the other board. I will get that tomorrow. Now, it is time to sleep.