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Author Topic: Can someone explain how a joule ringer and joule thief works?  (Read 11494 times)

rushi95

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Can someone explain how a joule ringer and joule thief works?
« on: February 19, 2018, 07:36:23 AM »
Hi,

I have failed to understand how a joule thief and a joule ringer works.

JOULE THIEF:
Basically there are 2 reasons for the transistor to turn off:
1. saturation of the transistor
2. Saturation of the core.
Do both work? Which is better? How do I know my joule thief is working on which of the above effects?

JOULE RINGER:
I completely fail to understand a joule ringer. The schematic is http://laserhacker.com/?p=59. I have not seen any explanation regarding a joule ringer. Can someone please help me to understand how the transistor is turning on and off and how is it oscillating.

Belfior

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Re: Can someone explain how a joule ringer and joule thief works?
« Reply #1 on: February 19, 2018, 03:20:34 PM »
I'll take a poke at this

In lasersaber's schematic at first C -> E is not conducting and the current passes through the lamp (resistance) and coil to the BJT base. When enough current gets to the Base the C- > E path will open. This path has less resistance than though the lamp and the current return through this path to the battery negative. Currnto the base will stop and the C -> E will close. Rinse & repeat

All this creates an on&off pulse at the toroid so you get a voltage spike and inducted power through the coils. So next round you get more current coming towards the collector from the battery positive side. The switching is so fast you see the LED on all the time.

Oh and joule thief and ringer are the same in my book. Give or take a few resistors or diodes they are usually the same. You have a resistance at the base (lamp or an actual resistor) so the C -> E will become the preferred route for the current to go and that is how it switches

rushi95

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Re: Can someone explain how a joule ringer and joule thief works?
« Reply #2 on: February 19, 2018, 04:51:04 PM »
Hi Belfior,

Thanks for your reply. I have still some doubts.

1. The bulb has to be resistive? Lets say we have 1.5V at the input. Can a 2V LED be used in this setup?

2. The battery will take the path of the bulb and then through the base emitter to the negative. Is the bulb lit during this time? The current through the secondary will support the current in the primary and that will in turn increase the current in the secondary. This will happen till enough base current flows to allow the transistor to conduct. Once the transistor conducts - the current starts reducing in the secondary and base and will eventually block the CE path of transistor. That will create a voltage spike in the primary coil. What happens next? What is the polarity of spike?

This is what I think - the current due to the spike will flow through the bulb and base again. Which will again increase the base current and whole process repeats. Is it correct?

According to this working:
1. Bulb is lit in both the phases of working?
2. Transistor is ON only for a very short duration. So, less heating compared to conventional JT where transistor is ON for almost the entire period.

Am I understanding all this correctly?

sm0ky2

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Re: Can someone explain how a joule ringer and joule thief works?
« Reply #3 on: February 19, 2018, 08:37:07 PM »
Sorry, I have to state my objection here.
(at the risk of starting yet another heated JT discussion)


I agree with Belfor’s statement that JT and JR are basically the same.
My understanding is that the ringer oscillations are in the audible spectrum,
where-as the JT generally operates at higher frequencies.
But both names are used interchangeably, and the device does not really have
a set specification.


However:  the “path of least resistance” concept cannot be the principal that
answers the question.
Simply because the transistor will switch without a load or LED in the circuit.
The LED/lamp/etc. is basically an indicator.


TK is probably the most able to give a better description


I have seen this device in too many variations, that any attempt to describe the
behavior, would cause argument. The most common form (found in “how to’s”)
is what most people discuss. But this is neither the simplest nor the most advanced.
So, in my opinion, it causes a lot of confusion for beginners. But I’ll give it a try::


If you ask me, I will tell you that while the inductor is charging (prior to saturation)
there is a current to the base. This opens the c-e gate
(or closes it, npn/pnp)
Once saturated, there is no more base current and the gate closes (or opens)
That might not be the best way to put it.


So, for a better understanding, maybe we should wait for TK to chime in.






rushi95

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Re: Can someone explain how a joule ringer and joule thief works?
« Reply #4 on: February 20, 2018, 10:55:48 AM »
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
 

sm0ky2

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Re: Can someone explain how a joule ringer and joule thief works?
« Reply #5 on: February 20, 2018, 11:02:46 AM »
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

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Re: Can someone explain how a joule ringer and joule thief works?
« Reply #6 on: February 20, 2018, 11:57:37 AM »
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

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Re: Can someone explain how a joule ringer and joule thief works?
« Reply #7 on: February 20, 2018, 12:12:08 PM »
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

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Re: Can someone explain how a joule ringer and joule thief works?
« Reply #8 on: February 20, 2018, 12:40:29 PM »
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

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Re: Can someone explain how a joule ringer and joule thief works?
« Reply #9 on: February 20, 2018, 12:58:20 PM »
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

rushi95

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Re: Can someone explain how a joule ringer and joule thief works?
« Reply #10 on: February 21, 2018, 12:45:27 PM »
Hi Brad,

It seems the capacitive coupling is creating an unnecessary amp draw. Any way to avoid that?

I am just wondering what happens at the primary side in a basic JT schematic during the inductive kickback phase? Is the inductive kickback reflected to the primary also?

Rushi

tinman

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Re: Can someone explain how a joule ringer and joule thief works?
« Reply #11 on: February 21, 2018, 01:07:18 PM »
Hi Brad,



 

Rushi

Quote
I am just wondering what happens at the primary side in a basic JT schematic during the inductive kickback phase? Is the inductive kickback reflected to the primary also?

Ok,not sure what you mean there,as you have !primary side! twice.
Perhaps you meant-what happens to L2 (secondary coil) during the inductive kickback cycle.

If so,then as i stated in my first JT post,L2 also inverts,and pulls the transistor off cleanly.

If you place two small LEDs across the 1k resistor as shown in the pic below,and a good 1.5v battery,both LEDs will light up when the JT is running.
This shows you that the L2 coil dose invert during the inductive kickback part of the cycle.

You now have a JT that runs 3 LEDs.  :)

Quote
It seems the capacitive coupling is creating an unnecessary amp draw. Any way to avoid that?

Nine times out of ten,you have a bulb in there,and so the capacitive coupling dose not play much of a part-as with all bifi transformers.
In some cases,the capacitive coupling is needed,as some bulbs will not allow current to flow in both directions--E.G ,LEDs.


Brad

sm0ky2

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Re: Can someone explain how a joule ringer and joule thief works?
« Reply #12 on: February 21, 2018, 10:00:07 PM »
If you want to get fancy, you can wrap a 3rd coil around the toroid
and draw power for a secondary device


https://youtu.be/h9RgjAgSQOg


But whatever you do, do NOT put 2 forward facing diodes
into a capacitor!
No matter the size, it Will explode

Belfior

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Re: Can someone explain how a joule ringer and joule thief works?
« Reply #13 on: February 21, 2018, 11:23:44 PM »
If you want to get fancy, you can wrap a 3rd coil around the toroid
and draw power for a secondary device


https://youtu.be/h9RgjAgSQOg


But whatever you do, do NOT put 2 forward facing diodes
into a capacitor!
No matter the size, it Will explode

Hmm what if you use a spark gap to get the extra energy out?

rushi95

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Re: Can someone explain how a joule ringer and joule thief works?
« Reply #14 on: February 23, 2018, 05:48:29 AM »
you can use pretty much any low voltage source
here is one I did with an “earth battery”

Hi Smoky,

Since last 2-3 days I have been studying about earth batteries, air batteries, water batteries, crystal cells, etc and I do not see any potential in lighting up the bulbs better than AA batteries. Let me know if I am wrong.

What I am looking for is a cheap solution (under 20$ and even less) to light bulbs in homes of poor people. I want to avoid solar panels and big batteries because the cost increases. Joule ringer seemed a good option. What I think is 10-15 minutes of human power would be capable of lighting bulbs for 3-4 hours.

It would be interesting if earth batteries were capable of doing that.