Joule Ringer!

[conradelektro]

@Stefan, bright CFL needs Watts, circuit does not like Watts

Even at 1 or 2 Watt (100mA to 200mA) the CFL is not really bright enough to count for a decent lamp. But already at 1 to 2 Watt the TIP31C transistors in the Joule Ringer circuit (or any Joule Thief circuit) overheat slowly (would need some decent cooling).

The only way I found to light CFLs according to their specified Wattage and brightness is the classical two transistor fly back circuit as shown below. You also find a similar thing inside the CFL lamps when you take them apart.

All Joule Thief type circuits are very hard on the transistor when the energy throughput goes up. There is no good way to adjust frequency, base-emitter current and transistor on time at the same time.

I found that Joule Thief type circuits are fun for low power and low voltage.

One has to be careful that base voltage does not go below ground and above collector voltage (which is easily induced by the trigger coil), both situations are bad for the transistor and damage it easily (especially when running from 12 Volt or higher). Also voltage spikes from the collector coil can cause very high voltages on the collector beyond 100 Volt easily (again when using higher supply voltages above 12 Volt).

Look at this page http://wiki.4hv.org/index.php/Flyback#High_Power_Drivers , it says it all very clearly (scroll up to read about the "Simple Circuits", which are the Joule Thieves).

I am very much a fan of Joule Thieves, but one has to use common sense when playing with them. There are no miracles and there are better circuits in case one needs useful Wattage.

I like the Slayer Exciter very much, because it is a safe way to build a Tesla Coil like thing. But its usefulness beyond a novelty item is doubtful.

The self made batteries are also very nice. May be not really useful, but educational. Some people said to me when I showed them some battery experiments: "Incredible, there is electricity everywhere once two metals are available". And this is the educational value.

Greetings, Conrad

[flathunter]

@conrad

Great post!

Although i do hope for more from exciters/joule thieves/flyback oscillators, i have to admit that what ive seen so far is exactly as you explain.  Thanks for all your circuits and diagrams - they have helped me immensely in understanding better and better these kind of oscillators.

@all

I can get the same ringing effect with a small xenon flash salvaged from a disposable camera.  It will continue for longer than 5 mins if left undisturbed, but the flash through the xenon gets weaker and less frequent as time goes by - the energy of the cap just seems to slosh back and forth, but each time becoming weaker and weaker (like a pendulum left undisturbed).  The xenon is smaller than 3cm end to end, and the starting pulse can be from a 12V, or 9V, or 1AA emergency charger combo.....though obviously the 12V is much more impressive!  Im using the tip31C darligton pair on a flyback circuit that conrad posted, except im using a neon in place of the high value resistor - i dont have any resistors in the megaohm range, and a 1 microfarad cap, as well as a 10000 microfarad cap to power it.   

Heres a poor quality vid:

http://www.youtube.com/watch?v=4jBqg63sYKY

@stephan
sorry - no idea about voltages as all multimetres are broken.  Also i dont know what kind of voltage is necessary to light a xenon.  But im sure there are some clever lads here who do.

[conradelektro]

@flathunter

Since I plan to go into fly back transformers (from PC monitors, the ones with the suction cap on the HV output) I am very interested in the fly back transformer you used in your xenon-flash-video:

- The fly back transformer should have two drive coils, or is that not so?

- Do you have the data sheet of your fly back transformer? If yes, I would like to know how they label the pins (names or letter codes), and which pins you used in the Joule Ringer circuit? May be you can give a link to the data sheet on the internet?

- Is the trigger coil (the one you put on the base of the transistor) completely independent of the drive coil (the one that goes to the collector of the transistor) or are they internally connected (like having a common ground)?

- Does it have an internal HV-diode?

- Would it be possible to remove the core of your fly back transformer? Or would one damage it completely when trying to do that?

Greetings, Conrad

[flathunter]

@Conrad
Im glad you're interested, but unfortunately im afraid ill be very little help.  I have no datasheet on the flyback - there is a sticker on it with the word SAMPO and some numbers - will they give us a clue?  Ill write them out if so.

Im using pins 1 and 2 (2 goes to collector)

5 and 9 (9 goes to base) (7 is also part of this coil....my multimetre would make the sound that means same coil.  And it'll work with 7, though not so well - perhaps a tap lead)

8 and rubber sucker as HV output

As for internal diodes - havent the foggiest.  Kooler told me that there may be internal caps when i first built a simple flyback/tranny circuit to drive a small jacobs ladder.  This was because i kept getting really jolting shocks - not just like your average HV tickle, but more like a cap discharge.

Internal connections between coils - sorry, no idea without datasheet.

My ability to take it apart it surely lacking - Im certain i would wreck it!  But people who know flybacks better than me could maybe do it.

Ive got another flyback of a much more ''old school'' variety which im gonna try very very soon.

Thanks again for the darlington pair idea - nothing would work till i tried it 

[conradelektro]

@flathunter

Please let us have the exact numbers, letters and symbols on the transformer. Is it too much to ask for a photo? I am pretty sure something can be found in the Weird Wide Wonderful net.

I am so (inexcusably) insistent because you got your fly back transformer to work in a Joule Ringer and very much can be learned from that about the connections.

The Darlington arrangement makes the base of the pair much more sensitive to the trigger coil pulses than a single TIP31C. That makes it easier to make the circuit oscillate. It was Bedini who proposed that in a post far up in this thread (or was it in energetic forum?).

I suck in all the ideas I see in the Joule Thief related threads and try to build something nice. Had great fun so far. I am not an electronic engineer, but I learned a lot since I started this hobby a year ago. Using the scope was a big hurdle and luckily it survived my learning curve. Now I want a better scope. May be I find an older second hand monster scope with two hundred buttons. My USB scope is nice, but very limited. Many transistors went to the trash pin, I could even burn capacitors and resistors.

Greetings, Conrad