Author Topic: Joule Thief (Read 6332469 times)

crowclaw · « **Reply #13305 on:** April 16, 2010, 05:16:01 PM »

Quote from: detrix42 on April 16, 2010, 03:54:11 PM

@crowclaw:
I have several working joule thief circuits, and have learned a lot. My desire is to run a Newman motor that I am building. I will need help in designing a JTC to deliver around 1000v. If you have not seen my videos yet here is a link to one:
http://www.youtube.com/watch?v=F6qLiAeyPng

I am willing to use, say a 12v source. I just need to know what is a proper transistor to deliver 1000v. I have used a disposable camera's flash transformer to get up to 350v from a AA battery. Technically, I am not concerned about how much current there is. In a Newman motor, it is desired to keep the current as low as possible and the voltage high. Though the coil in the video link above is only about 50ohms, and that would try to pull way to much current from my current JTC setup. I have come across some bigger transformers, and want to use them. So the question is, what components (transistor mainly) do I need to go from 12v to what ever I can get out of one of these transformers I have?

Thanks for your input Crowclaw, it has me thinking.

Hi detrix

OK You'll need a transistor that is well suited for high voltage pulse use, so go for one of the old TV scan output devices, many of these can cope with over 1200 volts VCE. There are many scrap TVs around since plasma and LCD sets have come along so take a look in disposal sights for an old set, older the better. The types you are after are BU208 or BU508 the "D" versions have an integral diode. Also older sets have usefull ferrite transformers to wind your coils with, or the line scan output transformer from a scrap TV could also be used. You will have to experiment with your base resistor value and I would use say 22R in series with a 1K pott for the base bias to "tune up" your circuit. Don't use laminated power type transformers as they tend to be OK for lower frequencies, you need to get fairly high frequency pulses. Be prepared to experiment to find the right voltage levels... you shouldn't have any problems otherwise; and with the right transformer the current draw should be within your spec. Let us know how you progress. Kind Regards

crowclaw · « **Reply #13306 on:** April 16, 2010, 05:19:16 PM »

@ detrix,

The transistor types I have mentioned are just two fairly common devices, however there are many others that will be suitable for your project with similar spec's. Regards

forest · « **Reply #13307 on:** April 16, 2010, 08:56:34 PM »

It should be possible to have JT generated 3kV from 4.5V input. I state that because I have now in my hand disassembled circuit from small ozone generator.Unfortunately it's all covered by epoxy resin :-(

detrix42 · « **Reply #13308 on:** April 16, 2010, 09:16:26 PM »

Ok, I am in the process of removing the flyback transformer from a 32" american television. Due to the high voltage that this thing can generate, I would like someone from this tread to walk me through steps to hook up a joule thief output to this flyback transformer. I only want about 1000v for now. I am trying to look up the pinout but I am not gettng anything from google with the part numbers I am seeing. (TFL2AA002 from a panasonic tv).

forest · « **Reply #13309 on:** April 16, 2010, 09:23:09 PM »

Quote from: detrix42 on April 16, 2010, 09:16:26 PM

Ok, I am in the process of removing the flyback transformer from a 32" american television. Due to the high voltage that this thing can generate, I would like someone from this tread to walk me through steps to hook up a joule thief output to this flyback transformer. I only want about 1000v for now. I am trying to look up the pinout but I am not gettng anything from google with the part numbers I am seeing. (TFL2AA002 from a panasonic tv).

Hmm..that would be hard task because TV flyback likes to generate much more then 1000v

detrix42 · « **Reply #13310 on:** April 16, 2010, 09:38:13 PM »

Quote from: forest on April 16, 2010, 09:23:09 PM

Hmm..that would be hard task because TV flyback likes to generate much more then 1000v

so your saying that if I hook up a JTC to a flyback transformer, I will get over 1000v??? From a AA batter no less??? wow.

MrMag · « **Reply #13311 on:** April 16, 2010, 10:03:01 PM »

Quote from: detrix42 on April 16, 2010, 09:16:26 PM

Ok, I am in the process of removing the flyback transformer from a 32" american television. Due to the high voltage that this thing can generate, I would like someone from this tread to walk me through steps to hook up a joule thief output to this flyback transformer. I only want about 1000v for now. I am trying to look up the pinout but I am not gettng anything from google with the part numbers I am seeing. (TFL2AA002 from a panasonic tv).

Here is a simple way to figure the pinouts in the flyback. First, check all of the pins with your meter. The set of pins that give you the least resistance will be your primary. To find your seconday winding, you will need a 12VDC supply or whatever you have handy. 24 would be better. Connect the positive of the power supply to the high voltage wire, the red wire that attached to the picture tube. Connect the negative from the power supply to the negative lead on your battery. Now take the positive meter lead and test each pin on the flyback. You should have a voltage on only one of the leads. This will be the secondary winding. If you don't get a voltage reading, try reversing the + and - on the power supply. Some of the newer flybacks have a built in diode on the secondary winding.

To hook it up, joule thief style, use the primary winding and then wind a second coil on the flyback ferrite to feed back to the transistor.

This should either help you or totally confuse you. I hope it helped.

conradelektro · « **Reply #13312 on:** April 16, 2010, 10:10:01 PM »

----------------------------------------------------------------------------
To all experimenters who helped me (Jeanna, Pirate88179, Gyulasun, Crowclaw),
----------------------------------------------------------------------------

your efforts were not in vain, after some trial and error I got a JT which is nicely lighting up three red LEDs in a row. See the attached images and the scope shot (its now 3.5 KHz). The frequency depends a lot on the number of turns of L1. The fewer turns, the higher the frequency. My blue Toroid needs quite a lot of turns for L1 (10 turns, see the attached schematics).

The hint about the value of the resistor between L1 and the base of the transistor was very valuable, it needed 330 Ohm.

The circuit consumes about 20 Milliamps when lighting 3 red LEDs in a row. On the scope shot you see, that the duty cycle over the LEDs is quite short, I guess this explains the surprising low power consumption.

The circuit and the toroid are now ready for a third winding (on top of L1 and L2) in order to implement Jeanna's light, which I will attempt soon.

There are better Toroids than the blue painted one I am using, but I wanted to make it work with this one, before I move on to other cores.

I am thinking a lot about an air core coil and will do some experimenting in this direction. Specially with three windings (for Jeanna's light) I see (more like a blind man) a lot of potential in a coil without any core. I am very much influenced by the GBluer(Slayer) Exiter.

------------
To Detrix42:
------------

Once I am a bit more experienced with the JTs, I want the same as you, namely driving light tubes and the new energy saving bulbs. For this I am studdying the thread

http://www.overunity.com/index.php?topic=8977.0 ( GBluer(Slayer) Exiter )

Read the posts of slayer007 and watch his videos on YouTube.

Greetings, Conrad

Pirate88179 · « **Reply #13313 on:** April 16, 2010, 10:11:35 PM »

Quote from: detrix42 on April 16, 2010, 09:38:13 PM

so your saying that if I hook up a JTC to a flyback transformer, I will get over 1000v??? From a AA batter no less??? wow.

If you use a Jeanna's Circuit, you can get over 2,000 volts output (or less if you want) using a simple TIP3055 transistor and running on a single AA battery!! No flyback coil needed. If you do use a flyback coil or car ignition coil, I would think you would have to rectify the JT's output as it will be a high frequency AC and not dc.

Less turns on the pick-up coil of the Jeanna's Light circuit will give you less voltage out and you can make it output whatever you need.

Lidmotor has a great schematic at the start of his video located here: http://www.youtube.com/watch?v=11nzbi59T7w&playnext_from=TL&videos=TVF4g87eQFw

You can do a screen capture and blow it up, that is what I did. Jeanna has also posted her circuit here as well but I can't recall what page.

Bill

detrix42 · « **Reply #13314 on:** April 16, 2010, 10:41:45 PM »

ok, I found a schematic of the whole circuit board for the tv. I will include it here. I don't see where the High voltage wire that goes to the tube is. argh.

Sprocket · « **Reply #13315 on:** April 17, 2010, 12:11:23 AM »

Quote from: detrix42 on April 16, 2010, 10:41:45 PM

ok, I found a schematic of the whole circuit board for the tv. I will include it here. I don't see where the High voltage wire that goes to the tube is. argh.

The pin marked "EHT". The standard o/p voltage from these babies is around 25k, after going through the 'tripler' - though it of course depends to your primary voltage...

detrix42 · « **Reply #13316 on:** April 17, 2010, 01:34:18 AM »

ok, ok. The Flyback transformer may be a bit overkill. I am considering it because I don't have access to a 3.5" toroid. I have a bunch of 1" toroids, and a couple of disposable camera flash transfromers. hmmmm. I still don't know how to use the output of the joule thief in my motor. My third motor's coils have a resistance of 1155ohms. This draws to much from my JTC. I plan on adding a lot more wire when funds allow.

So in the mean time, I would like to get the Flash transformer to lite a CFL. I think I can do this.

tysb3 · « **Reply #13317 on:** April 17, 2010, 03:34:16 AM »

Hi detrix42
with soldering iron 60W you can remove rod from flyback transformer.
need to heat rod about 6-10 min (glue become soft), after carefuly release by knife.
maybe need heating twice or more

resonanceman · « **Reply #13318 on:** April 17, 2010, 05:07:01 AM »

Quote from: detrix42 on April 16, 2010, 10:41:45 PM

ok, I found a schematic of the whole circuit board for the tv. I will include it here. I don't see where the High voltage wire that goes to the tube is. argh.

Detrix

you don't need a schematic to make a flyback coil work as a JT

Just check the continuity of all the pins.
The high voltage lead coming out of the top will probably have continuity with one or 2 pins..... this is your secondary.

you will probably find several pins that have continuity in a row.
These should be low resistance ....... these are your primarys.
Just connect your C , E and B+ to these pins and check for output
I do not know what kind of voltage these will put out...... my meter only goes up tp 600 V .....it is higher than that.

````````````````````````````````

SOmeone posted the standard connecrtions for flyback transformers on the JT thread.........it has been a while....... I have no idea how far back to look.

gary

resonanceman · « **Reply #13319 on:** April 17, 2010, 05:35:31 AM »

Quote from: conradelektro on April 16, 2010, 10:10:01 PM

----------------------------------------------------------------------------

I am thinking a lot about an air core coil and will do some experimenting in this direction. Specially with three windings (for Jeanna's light) I see (more like a blind man) a lot of potential in a coil without any core. I am very much influenced by the GBluer(Slayer) Exiter.

conradelektro

Air core coils are no problem......in general you just need more wire than if you used a core.

It is possible to light a LED with only a twisted pair of wires.
From my experience the pair has to be at least 6 ft long.

It may seem meaningless to light a diode with just a wire.........below is such a JT .......only I have wrapped the wire a few turns around a toroid with a secondary .......it is driving a 90 LED array

Edit
When adding toroids in this manner you can use a shorter twisted pair........ if you add a few toroids you may not need any extra twisted pair other than for connecting ther toroids.

If you add too many toroids the inductance will choke the circuit...

```````````````````````````

I have also made a JT out of 150 ft of cat5 cable.
I used one pair as primary and connected the rest of the pairs in series as secondary.... it worked very well........but it was very large.

gary

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Author Topic: Joule Thief (Read 6332469 times)

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