Joule Thief 101

[Nink]

He should go beat up Clock Boy and then sail off in a balloon.

I get how the Radio Shack clock shoved in a case works but what does the spoon stuck in a tripod do ?

[Pirate88179]

I get how the Radio Shack clock shoved in a case works but what does the spoon stuck in a tripod do ?

That is the remote detonation device reflector.  It is not on the original schematic.

Bill

[tinman]

Brad:
  This is what I have been trying to do for years with zero success.  I don't have a strong enough AM station near me.  Congratulations on doing it.  Please make sure that you are not getting any energy from the scope ground lead  A ways back a bunch of us tried to replicate Dr. Stiffler's PSEC only to find out the power came from the scope ground he had hooked up.    To really convince people what you say is actually happening you will probably have to take the whole setup outside.  I hate to say that but I see it coming.  If you are getting that much energy into the system without a big/long antenna then you have stumbled onto something wonderful.  Frankly even if the energy is coming from somewhere else I would like to know about it anyway.

MH:

  I have been looking at that 'out of the box' circuit you presented and backed away from it.  Too much work and not enough fun factor for a hobby guy like me with poor test equipment.  I did try something a little different based on it though.  I built a simple flip flop circuit and drove two separate NPN transistors off that.  The NPNs pulsed two 1mH chokes with leds across them backwards to make the light.  I powered the flip flop with a 3v coin cell and the inductor circuit with AA.  I made an interesting experiment but was horribly inefficient.
  Here it is and what it looked like on the scope:   https://www.youtube.com/watch?v=_X_g52LsVnU

Hi Rusty.

I will look into it further for sure. I did think about the scope ground,but it is just a common ground,and i also have it hooked to the positive side of the cap,with the scope channel inverted.
That particular radio station is only about 4km away from me,and the reason it is the strongest signal in my area. That little electronics kit allows you to build a fox hole type radio receiver,and it works very well. Going to go down to my local electronics store today,and see if i can buy one of these ferrit core aerials today,and build it on a plexiglass board--just for clarity.

Brad

[MileHigh]

author=MileHigh link=topic=8341.msg475491#msg475491 date=1456418556]

MileHigh

So show us your smart's MH--design a simple circuit that lowers the base resistance as the voltage in the battery drop's. You pride your self on bench time and knowledge,so show us some of that smarts. You draw up the circuit,and i'll spend the time and money putting it together,and testing it. I'll post the results and video's here.


Brad

You have to back up first.  Who says that you need a variable resistor for a Joule Thief?  I am not aware of that requirement.  The only thing that I am aware of is that it was done all the time in the old days of this thread, presumably without any serious circuit analysis or scope work done to see what was happening.  It was just an anecdotal observation that the LED changed in intensity when you changed the base resistance.

You are suggesting it so it suggests a question for you:  Why do you want to have a variable base resistor in a standard Joule Thief?

No response on this and I am not surprised.  This is an example of leading yourselves down a garden path.  You talk about varying the base resistor "just because" and you can't actually explain why you want to do it.

Likewise, I will predict with high confidence that nothing will come from a "resonant Joule thief."  It's another idea where you can't actually say why you want to do it.  I speculated that you might get better performance because you may be emulating how a standard DC-to-DC converter works, which means that "resonance" has absolutely nothing to do with it at all.  The silence was deafening.

There is no point in approaching electronics like this, sort of like alchemists.  You need to approach electronics like chemists.

[tinman]

No response on this and I am not surprised.  This is an example of leading yourselves down a garden path.  You talk about varying the base resistor "just because" and you can't actually explain why you want to do it.

Likewise, I will predict with high confidence that nothing will come from a "resonant Joule thief."  It's another idea where you can't actually say why you want to do it.  I speculated that you might get better performance because you may be emulating how a standard DC-to-DC converter works, which means that "resonance" has absolutely nothing to do with it at all.  The silence was deafening.

There is no point in approaching electronics like this, sort of like alchemists.  You need to approach electronics like chemists.

Do you need an answer to understand the need for a variable base resistor MH?-or will your batteries simply remain at the rated voltage of 1.5 volt's?.
That was a bit of a silly statement by your self MH.

Asking why the need for resonance is also a silly question.
Try pushing a child on a swing both in and out of resonance,and see which uses more energy for less motion. Why can you jump higher on a trampoline with less effort,than you can on the ground with more effort?.

MH-are you board again?.


Brad