Joulethief SEC exciter and variants

[xee2]

@ jonnydavro - about flyback

Attached is a circuit using only one resistor that you might want to try also (it is a Joule thief circuit).

I do not think a flyback will work as well as your simple SEC for wireless stuff because it works at a much lower frequency and therefore less energy is capacitively coupled through a given capacitor value. My flyback was working in the low KHz range. I suspect your simple sec is working in the MHz range. That is a difference of about 1000 in energy coupled through a capacitance.

Hmmmm...... My circuit was converted to a smaller size by the forum software. The result is a bit hard to read. Sorry, I am still learning how to do things here.

[Inquorate]

Images

@ xee - I just post images externally, there's not much space allowed here per user. I use Free Blogs, Blog Hosting & Photo Sharing at Vox.com

[jonnydavro]

@Xee.Hi.Have you tried removing the rectifier from one of these flybacks so you get AC or used a really old unrectified one as this is what we need to see sec?
This may not have the SEC output of the simple sec for reasons you have stated but the dc output of this circuit is very high for the power needed to run it and when you see angry looking neons,you know there is potential for lighting a fair few leds and maybe some charging.
I will try your circuit and let you know how it goes.Have you tried it and found it to use 10mA?Jonny

[sucahyo]

I do not think a flyback will work as well as your simple SEC for wireless stuff because it works at a much lower frequency and therefore less energy is capacitively coupled through a given capacitor value. My flyback was working in the low KHz range. I suspect your simple sec is working in the MHz range. That is a difference of about 1000 in energy coupled through a capacitance.

Would removing the core help? it is removeable isn't it?

If you post image as gif or png, it will converted to small jpg, it is best to post it as jpg.

[xee2]

@ jonnydavro - flyback

@Xee.Hi.Have you tried removing the rectifier from one of these flybacks so you get AC or used a really old unrectified one as this is what we need to see sec?
This may not have the SEC output of the simple sec for reasons you have stated but the dc output of this circuit is very high for the power needed to run it and when you see angry looking neons,you know there is potential for lighting a fair few leds and maybe some charging.
I will try your circuit and let you know how it goes.Have you tried it and found it to use 10mA?Jonny

I have not removed any diodes. But, Yucca has. He said it was not hard to do. I did not want to risk breaking my flyback. If you do, please post results. But, the flyback technique of voltage multiplication does not produce AC since the rapid current change is always with the same polarity. I think the diodes are mostly to keep the capacitor (picture tube) from discharging. To get AC I think you will need to use a two transistor driver.

Yes, I made the circuit a while ago and it lights the tube with 10 mA from 1.5 volts. I like this because there is only one resistor to change. But of course, two resistors gives more options. I have used it up to 9 volts.

For some reason which I do not understand, the Joule thief + trigger coil circuit produces AC (or at least symetric plus and minus pulses). I was able to get high voltage AC that way. But, there is still the low frequency problem. You should be able to use the flyback transformer in place of the trigger transformer if you want to try this. I have been able to light a 4 watt tube without any wires to the tube at all from 3 volts using this circuit, but only when tube was right next to the circuit output wires.

circuit = http://www.overunity.com/index.php?a...0;attach=41557

[xee2]

If you post image as gif or png, it will converted to small jpg, it is best to post it as jpg.

Thanks. I had posted as a GIF so that explains what happened.

If the core is removed there is not much of a transformer left so I do not think that will help.

[jonnydavro]

Hi Xee2.The flyback i have is sealed with resin and looks like a real mare to get inside without breaking something so i will not try with this flyback.I have another from an old computer monitor which are not really good for arcs as they have an internal capasitor so the output is slow pulses so i may have a look inside that but an old one would be an easier way.
Your joulethief trigger circuit is similar to my joulethief sec exciter so i will try it in there.
YouTube - Joulethief SEC Exciter-wireless energy transfer.
I did try the monitor flyback with a modified simple sec circuit after talking with ABCStore who has been using a simple sec with 1 meg resistor to run transformers and it would light a neon on 000.0mv measured across a one ohm resistor and 0.000V/0.001v TRMS so i found a use for itRegards jonny.

[marxist]

purpose of the neon

Hi jonnydavro,

the neon which you put across emitter and collector in your circuit

does it protect the transistor or is it just to show the high voltage which builds up between emitter and collector?

Thanks.

edit: I am trying to build such a circuit using 2 AA batteries in series and got my transistor whining and the neon shining, but don't get a HV spark yet. But my voltage divider is not according to your specifications (yet).

[xee2]

@ marxist - flyback circuit

You might try the one resistor circuit I posted above. It is easier to get it working and it will produce small sparks at 1.5 volts if the resistor value is decreased. Neon does protect transistor, but it also steals a little power from the output.

[marxist]

happy

Thanks xee2,
Got it to run from 2 AA batteries with your circuit and a 2n3055.

Had several problems initially:
Had tried a BU208D which did not work,
Did not try with my one and only 2n3055 for fear it might fry ...

Several questions:
1) Can I also protect the transistor with a diode?
2) If I want to go to 9 V batteries or other higher supply voltage, do I have to increase the 'base resistor'?
3) how can I find out whether my flyback has AC or DC output?

Thanks to all.

PS Picture is just for fun. It does not arc at the moment, as the HV line is too far from the 'target'

PPS xee2, you can reformat your image to ca. 800 pixels width before uploading, then it will display ok. I use the program irfanview
IrfanView - Official Homepage - one of the most popular viewers worldwide
to do resizing of images and such.

[xee2]

@ marxist

Thanks xee2,
Several questions:
1) Can I also protect the transistor with a diode?
2) If I want to go to 9 V batteries or other higher supply voltage, do I have to increase the 'base resistor'?
3) how can I find out whether my flyback has AC or DC output?

1. Use several diodes in series. You should do this if you use 9V with 2N3055. Problem is the Vceo voltage of transistor (collector-emitter voltage that will zap transistor). Find transistor with a high Vceo voltage if you can.

2. No. But you might want to.

3. Put neon on output of flyback. If both electrodes light it is AC. Be careful not to be fooled, sometimes hard to tell if electrode is lit or not.

[jonnydavro]

@Marxist.Hi.Nice work getting Xee's circuit going.I must admit these flybacks are great fun to experiment with.
The reason i put the neon across the collector/emitter was twofold.One was protection although the 3055 is a hardy beast and the other was to show how much voltage is available there for doing other things like lighting leds or charging batteries etc and this voltage is usually neglected.
Transistor choice is quite important for this and the 3055 is tough and works but there will be better transistors to try,it is just a case of experimenting and the voltage devider is important also and makes my circuit highly tuneable,but i think your only 3055 should be safe at this low voltage.
The flyback transformer you are using looks quite old and there may be a chance it is ac so Xee gives good advice as well as great circuits so best check with the neon.If it does proove to be an ac flyback,you should see wireless sec effects which i would be really interested in if you see anything like that.Happy experimenting.Jonny

[marxist]

measured frequency range

Just to let you know my finding using xee2's circuit:
- only 1 electrode of a neon on the output lights up, so my flyback is DC.
- according to my measurements - using a 2N3055 transistor and an oscilloscope - my flyback circuit works at approximately 0.5 to 1 kHz @2.5 V input and at approximately 1 to 2 kHz @ 9V input.
- the higher the frequency the more I have to narrow the spark gap, otherwise there is not enough power for the spark to jump over.

[marxist]

50 Ohm why and possible substitute for pulse trafo

Hi jonnydavro,

I have two more questions:
- about the 50 Ohm in your circuit:

Why are they there, when there is the 1k potentiometer behind them?
Is it for safety, so that if you 'fully open' the two potentiometers (both to Zero Ohm), there is still the 50 Ohm to prevent a short circuit of the battery?

- do you think it may be possible to use a flyback as a substitute for the pulse transformer in the 'simple sec' (as it also creates HV pulses)?
I am asking this, as I never made any kind of sec, but am tempted but have no pulse transformer.

btw doc posted new vids
YouTube - MRH2O2's Channel

[jonnydavro]

@Marxist.Hi.The 50 ohm resistor is there to prevent a short if both pots are zero'ed like you thought.
The transistor choice makes a big difference to the size of the arc's.I had a rummage in my junk box and found a 2n6677 and that produces 1cm arc's from 1.5v and also the original transistor from the tv works just as good which was a toshiba and has D2253 on it.
Regarding using a flyback in a sec circuit.I put the first flyback i had from a computer monitor in a simple sec circuit with a 1 meg resistor across collector/base and it would oscillate but i could not get it to draw much current but it would light a neon on microamps but i did not see any sec effects as i could not drive it hard enough maybe.
I have seen some sec effects with both my circuit and Xee's as there is not much between them performance wise,mine may go a little lower on amp draw with flouerecents but otherwise not much difference.If you look at my circuit and remove the 50 ohm and bottom pot,you have bascically got Xee's circuit in reverse and this works good too.I will have to try a small joulethief in that config.To see some wireless and one wire sec effects is what i did was i added a 22uh rf choke as an L2 coil after the primary of the flyback which was acting as L1 and there is a wireless output but not strong but worth another look so it may be possible to get a good sec output.I think it is a question of driving the flyback at a higher frequency.Regards jonny.