Joule Thief

[TheNOP]

@jeanna
you seem amaized that the currents goes down when more leds are added.

take a few resistors and a power source.

put one resistor and measure the currents
add an other resistor in series, measure the current again
add a third resistor in series, measure the current again.

what conclusion can you make from that experiment ?

me, i came to this:
resistors in series are not current dividers
the resistors are placed in series in order to increase the resistance, therefore decrease the current in a circuit.

and if, like me, you also took voltage measurements:
resistors in series are voltage dividers
the current is the same in all resistors connected in series.
the same current flows through each series resistor.

with this experiment, you have prouved Ohms law.

the same can be done to explain the load/no-load currents behaviors.
your experiments with transformers, will bring you to Faraday's, Maxwell's, Lenz's, Ampère's and Lorentz's finding on induction.

[jeanna]

Well, theNOP,

I am unable to talk (let alone argue) theory with you or anyone else.

I do not believe the amps draw on a circuit is lower with 3 resistors in parallel than one resistor in line. The volts across those resistors will drop. I remember that from the beginning DC currents book I borrowed from someone a while back.

In fact, I was under the impression that the resistors value would add up to the same amount as the one when more were added in parallel to this. Using E=IR the lower the volts value passing through each resistor, the more amps draw.

I think this how house lighting is set up. All the plugs in your house are in parallel to the trunk line and as you add resistors more amps are drawn into use and they have a way to bill you.

I could be so totally wrong about this that it would be silly to even talk about it. It is how I thought things were. That is all. I am new to this subject, and easily confused.  You already know that.

jeanna

[jeanna]

Hi everyone,

I wrote this little description of how to make a 2 tiered joule thief circuit.
It it simple for anyone who has made a regular one.
It is especially easy to make this on a breadboard.

So for anyone who wants to see what this is doing,
and maybe help figure out what it is doing,
here:

I will also repost the drawing.

=====
Make 2 separate joule thief circuits.

Make them out of similar components and sizes, turns, number of secondary winds etc.

Test each one separately for amps draw with and without a LED in the BJTL spot.
Leave the BJT LED in place.

On both circuits, fix a good wire to the ends of the secondary.

Decide which will be tier 2.   NOW, Remove the BJT LED from tier 1.

On tier 2, find a comfortable spot to put the secondary for LEDs
Put one secondary wire into each row.
Place 1 LED in parallel into this spot.
(Now, tier 2 has 2 LEDs, one in the usual place, and one in this secondary spot.)

Using the secondary wires from tier 1, fire up tier 2 by placing one secondary wire in the + and - of the second tier battery rail.

Go ahead and turn the circuit on with the basic battery feeding into tier 1.
Notice the light.
There may be just barely a dim spot of light in one or there may not be any. You could adjust the base resistor, but don't bother yet. Don't worry for now.

Remove the tier 2 transistor and resistor.
Nothing will change.
Take the toroid lead that used to be in line with the base resistor, and jumper it to the negative leg of the LED in the secondary spot.
And move the secondary lead from the same spot (negative lead of the LEDs) and now place it into the negative battery rail. (second tier still)
Kaboom, the lights will get bright. watch your eyes!
====
Next time you won't need to go through all the extra steps. It is better this way for the first time. OK?

jeanna

---
After rechecking I must report that I burned out my battery holder while using this circuit last night.
The connector on the outside of the neg black connection is gone with a little discoloration.
The battery is OK and the spring on the neg inside across to the end of the red pos wire is also fine.
Just the outside of the neg side.

I do not know what this means, but please do not walk away with this plugged together until we figure this out.
j

[TheNOP]

you are right about resistors in parallel.
they are current dividers.
voltage stay the same across each one.
currents goes up each time you add a resistor.

my example was not to tell you how your circuit work.
it was merely an example to let you see such a currents behavior is possible.
it is not just theories, those are verifiable faqs, that is why they are call laws in the first place.


what is not obvious in my previous post is:
although you can measure a coil resistance, voltage and currents,
Ohm's law will not apply if the voltage and currents are induce with a magnetic field.
when there is induction, Ohm's law does not hold anymore.
Ohm's law still apply to circuit on both side of a transformer separately, but does not apply for what is happening between the two.

there are ways to make a transformer Acts like you see(currents wise) in your circuit.
adding more load lower the currents.

but there are also ways to make a transformer do exactly the reverse.
adding more load draw more currents.

we are not dealling with resistance then, we are dealling with impedance.

for simplicity, let say that impedance is just a variable resistor that can change with a load.
if adding a load reduce the impedance of the primary winding, more currents will flow through it.
if adding a load make the primary winding impedance higher, less currents will flow through it.

[Mk1]

@all

I have found other toroid that give me higher voltages like the green gem , charcoal about one inch , in good supply .
I may even make kits now so no more excuses , i would not make kits unless i had good toroid , but now i do !

Some voltage , ok on a regular jt 1k base resistor 2n2222 , on 15 turns i get 64 v rectified dc , i also made a pancake pickup coil 16 turns it gives 70 volts rectified dc , leds light both ways like the cross windings , its not clear what is the best , so testing will need to be done.

Good work everyone ! page 500 is around the corner not bad for a tread that started last November !

Mark

Thanks to all of you , i have hope for the future ! He Jeanna is burning plastic , way to go Jeanna ! 

I am willing to send one to you koen1 !