Can someone explain how a joule ringer and joule thief works?

[sm0ky2]

They are used by self-experimenters for "dead-battery" recycling
and tinkering around, with whatever "use" the person sees fit


Taught in some colleges as a novelty


But as far as I know, the only place they have shown up commercially
is in some Chinese LED light bulb circuits.
And I remember someone finding it hidden in a Chinese solar light.

[Belfior]

Thanks sm0ky2,

You are right. I am just a beginner to joule thief circuits and its getting confusing to understand the right working of its variants like joule ringer.

Can you please help me know where joule thief circuits are used?

If I have low voltage input, I can use a boost converter to light up the LEDs. And even the joule thief does the same job of boosting the voltage. Which is more efficient and practical to use for lighting applications? Any thoughts?

I got interested in joule ringer circuits because I see LED bulbs can be lit easily with 1.5V AA batteries. I could see them being used in villages to lit homes of poor people for 3-4 hours on a single charge. They could be recharged either through solar panels or hand crank generators or bicycles (10-15 minutes of human power can recharge a single AA battery). Would they work as I have described? Or am I missing something?

And will wait for TK to help in understanding the working of a joule ringer.

Thanks,
Rushi

I think you could use something like Tesla radiant energy patent https://patents.google.com/patent/US685957 and a joule thief to get an LED to light up. Insulated copper plate as the antenna you can pick up enough EM from space even during night time. Not much power, but that light will make a big difference in a pitch black outhouse in the middle of woods...

[sm0ky2]

you can use pretty much any low voltage source
here is one I did with an "earth battery"
https://youtu.be/1v0ik0MyhZ0


mine sucks


Here's Bills
https://youtu.be/5kL8ys8m0-4


my older brother makes JT's in Altoid tins
using tiny (1/4") ferrites, he got one to light up
from his metal computer desk, which he had discovered
was gaining a potential, when the pc was on.

[tinman]

First i will explain how the JT work's,as the Joule ringer works a bit different,and will explain that in the next post.

Below we have the most common JT circuit .

When the battery is connected to the circuit,there is enough current flow to the transistors base(via L2 and the 1k ohm resistor)to start the transistor conducting.

Once the transistor starts to conduct, a small current starts to flow through L1.
When this happens,the current flow through L2 starts to increase via the transformer action between L1 and L2.
Because the current flow through L2 increases,it continues to pull the transistor on harder,and again increases the current flow through L1.

So you have this cascade effect,where the current continues to rise through both L1 and L2 until the rate of change of the magnetic field reaches it's limit.
Once there is no longer any rate of change of the magnetic field(maximum available current from the battery has been reached,the transistor switches off.

When the transistor switches of,the voltage across both L1 and L2 inverts.
Because the voltage has inverted,L2 now pulls the transistor hard off.

The voltage has also inverted across L1,and so you now have the correct polarity for the LED to light.

Remember,in both cases,the current continues to flow in the same direction through L1 and L2--only the voltage inverts.

Hope that helps

Brad

[tinman]

Ok,now the Joule ringer--V3 in this case.

This works a little different to that of the JT.

You will note that some have already stated that both work(oscillate) without the LED(in case of the JT),or a bulb of any description in the case of the joule ringer.

If we look at the joule ringer circuit below,you may ask--well how dose the transistor switch on if the bulb is not in place,and there is no closed path for the current to flow to the base of the transistor 

Well,you will see i have added a capacitor across the L1 and L2 winding,and this represents the capacitive coupling between L1 and L2.

So now we have a path for the current to flow through,that path being by way of displacement current due to the capacitive coupling between L1 and L2.

So,this is how the joule ringer will keep oscillating even when the bulb is removed.

You will find however,that once the bulb is in place,the power draw of the system will also go up.


Hope that helps.

Brad