Joule Thief 101

[Magluvin]

Off topic.
I have a ship n shore battery charger. Switching supply type. 

I pulled the plug out of the wall and got seriously buzzed by touching the plug ends, after it was out of the socket. It has a digital disiplay and a fan which stays on for say 4 to 5 seconds without a battery connected.

The input, 120v ac is bridge rectified to a cap and switching supply, etc etc.

The shock was more like a buzz. I could tell the difference between dc and pulsed current. So im just wondering. If it wasnt dc from the cap leaking through the bridge, if that could even be for how bad I was shmacked, could it have been that the input was say trying to pull pulsed currents into the circuit, through me? Hard to explain the idea. Like as the input cap discharges because the circuit will try to operate as long as possible, is it possible that the circuit is trying to pull more than what the cap has, if it can.  Lol I dunno. Ill have to run some tests on that thing.

Mags

[tinman]

Below is a scope shot of a JT type circuit in resonance.
I used a center tapped transformer,and have two LED's on each half of the center tap.
The circuit frequency was raised and lowered until maximum amplitude was had across the LED's,and minimum current draw on the P/in. When out of this resonant frequency range,the LED's would dim,and the I/in would increase. From this simple test,we can easily see why resonance is important in a JT circuit.
The second scope shot is across the 100ohm P/in CVR on the ground side of the circuit.

Brad

[MileHigh]

Brad:

Resonance is two components of a system that work in harmony.
With a JT,those two components would be between the induced current into the inductor,and the rise and fall time of the magnetic field. When the timing and duration of the induced current is in harmony with the rise and fall time of the magnetic field,then you have resonance.Current is the man pushing the child on the swing,and the child is the rising and falling magnetic field.

"Two components of a system that work in harmony" is pretty much meaningless, and it's wrong.

I said no bait and switch on the definition of resonance.  We are talking about electrical resonance or it's mechanical equivalent.

"Induced current into the inductor" and the "rise of the magnetic field" are the same thing. 

Current is the man pushing the child on the swing,and the child is the rising and falling magnetic field.

If you are trying to explain how a child on a swing is a resonant system then you are off by a country mile.  Not even close.

Many times it has been said that efficiency (in the case of the JT) would be the maximum conversion of electrical power,where we take a low voltage,high current,and convert that into a higher voltage,lower !overall! current that we can use to drive our LED.

Your description of how a Joule Thief operates isn't even close, it isn't even in the ballpark.

Resonance increases the efficiency of this conversion,as it reduces the overall waste heat,due to the system components working in harmony

Meaningless.

The only thing happening to me right now MH,is me wasting my time trying to explain as to how resonance can increase efficiency's in many different type's of systems.

Looking at what you are saying above, you are not explaining, rather you are just exposing how far you have to go to get where you want to be with respect to electronics.

So now tell me that an ICE has no resonant operations taking place that increase not only the power,but also the efficiency.

Your description has nothing to do with electrical resonance or it's mechanical equivalent.  A wine glass is a mechanical resonator and I asked you to show your smarts and explain how it works and how the resonant frequency is determined.

Resonance= operational harmony between system components.

I an sure the term "resonance" is thrown around a lot in the automotive trade, but this is not a discussion about the automotive trade.  It's a discussion about electrical circuits and the Joule Thief and the way resonance is defined as an engineer would define it for electrical circuits and mechanical systems.  Resonance is a word that really means something and you are not going to change the definition of it.

MileHigh

[MileHigh]

If you have ever ridden a dirt bike with a 2 stroke engine, there is an area in the rpm range we used to call the power band. And when you experience it for the first time, it can scare the boogers out of you.. This area of the rpm range is very powerful and for reasons brad speaks of.  Changing the exhaust pipes/muffler, intake changes effect where this power band is in the rpm range. Usually the factory has it right, but you can tweak for more. It usually happens in the upper rpm, so it builds on you in each gear. It is where the engine has everything going for it as in, the intake and the exhaust are tuned for that particular audio freq and intake and exhaust have enhanced ability to give the engine more in and easy out and not have to work really hard to get it, as in creating suction for intake and having to push out high pressures of combustion. So the engine has more power out due to very little losses from the intake/out take cycles.  Plus a 2 cycle is a full cycle per revolution, and a 4 cycle is a single cycle per every 2 revolutions. So the 2 cycle can produce more of a pure wave rather than a reduced duty cycle of a 4 stroke.
2 strokes are amazing machines and very simplistic with the least amount of moving parts.

Mags

Indeed, for just about any gas engine there is a power band.  Don't racing car drivers shift gears and try to stay in the power band to maximize their acceleration as they increase in speed if that's what the want to do?  It's maximum horsepower out vs. engine RPM.

However, in the language that we use on the forums the power band is akin to a sweet spot that is quite wide as opposed to being a narrow sweet spot.  The point being that it is a sweet spot and not "resonance" in the engineering mechanical or electrical sense.

MileHigh

[tinman]

Brad:

"Two components of a system that work in harmony" is pretty much meaningless, and it's wrong.

I said no bait and switch on the definition of resonance.  We are talking about electrical resonance or it's mechanical equivalent.

"Induced current into the inductor" and the "rise of the magnetic field" are the same thing. 

If you are trying to explain how a child on a swing is a resonant system then you are off by a country mile.  Not even close.

Your description of how a Joule Thief operates isn't even close, it isn't even in the ballpark.

Meaningless.

Looking at what you are saying above, you are not explaining, rather you are just exposing how far you have to go to get where you want to be with respect to electronics.

Your description has nothing to do with electrical resonance or it's mechanical equivalent.  A wine glass is a mechanical resonator and I asked you to show your smarts and explain how it works and how the resonant frequency is determined.

I an sure the term "resonance" is thrown around a lot in the automotive trade, but this is not a discussion about the automotive trade.  It's a discussion about electrical circuits and the Joule Thief and the way resonance is defined as an engineer would define it for electrical circuits and mechanical systems.  Resonance is a word that really means something and you are not going to change the definition of it.

MileHigh

MH,your an idiot,and im done with you and your bullshit.
You bring nothing to this forum,other than negativity,and dismiss everything anyone says about resonance.
Tell us all again how there is no resonant features used in ICEs to make them more efficient and powerful -->proved you wrong there without a shadow of a doubt.

The induced current into an inductor and the rise of a magnetic field are not the same thing at all. They are two different thing's,and one results from the other.
When the current flow into the inductor is interupted(shut off),the magnetic field still exist,and now the current flows from the inductor,in stead of into the inductor.

Face it MH,you dont belong here with your negative and incorrect attitude.
Your way out of your league when it comes to resonant systems in an ICE,and i have shown you just how far behind the 8 ball you are.

Out of the two of us,i was the only one to correctly explain as to how the JT circuit was working at low voltages,while you were to scared to even have a go at explaining it.
There is one of us here that is way behind MH-thats for sure,but im afraid it is you,and the proof is plastered all over this thread.

No resonant factors in an ICEs performance
Laughable


Brad