Joule Ringer!

[stprue]

@stprue

Nice equipment you have and good work you have done.
The playlist of your videos is kind of slow on my machine.
I saw as many as I could.

The how to make a sec is the one configuration I was talking about with a camera trigger.

Jesus

Sorry about the slow speed, I upload in hi def.

[e2matrix]

Just a thought for lasersaber or others who have been having success with getting CFL's lit to maybe make this a self runner.  I've noticed CFL's do power solar cells fairly well as opposed to LED'S which barely can move a voltmeter on most solar cells.  I just laid a 20 watt CFL on a very small solar cell and got 17.98 volts although only about 2.5 ma.  That is running full brightness from mains power but maybe 4 of them at lower brightness would do that much or more. 
   
   I know solar cells are very inefficient and there may be other ways to harness the energy but no use in throwing away the light if it could tip the scales to the point of self running. 

[e2matrix]

Finally the sweet smell of success    That is after blowing out my Fuji transistor after about a 1 or 2 second run.  My Fuji AA camera had a D2607 transistor.  It wasn't working but after some playing around and reseating the transistor on my board it fired up the 14 watt CFL quite bright but instead of using a cap on that try (after reseating ) I was using a 12 volt Ni-cad pack at about 13.5 volts.  The magic smoke appeared in about 1 second.  I tried a couple 2n2222a but no luck.  Next up a IRF640N - I'll try anything.  I'm sure this is not a great choice but success!  It was dimmer than with the Fuji transistor but this one lasted and lasted.  I got 4 minutes and 35 seconds on a 40,000 uf cap charged to 13.55 volts.  I used a good 1N4937 diode paralled with a 2.0 Megohm resistor across the bifilar.  The bifilar BTW is an oddity itself as it's one wrapping on a roughly 8" diameter toroid made of copper tubing (the type used for coolers which is 1/4" inside diameter) and the tubing is about 15 turns making an 8" diameter toroid outside with inside about 6" diameter.   Light went out when the cap reached 3.3 volts on this one
   I also ran the test with one 8200 uf cap and that lasted 47 seconds with a starting charge of 13.3 volts.
Another test with a 31,000 uf cap with a starting charge of 12.15 volts lasted 3 minutes 25 seconds.  All the caps of have are quite old and have kicked around a lot with a fair bit of abuse I'd say. 
   I had some fairly odd results using a 10,000 uf cap charged to 13.5 volts.  In both cases it blew out my IRF640N.   It had less charge than the 40,000 uf cap so I don't know what happened there. 
   Fascinating circuit.  I hope I can find an affordable transistor that can run this brighter beside the Fuji.  I think the Fuji would have lasted if I had started with the cap only and used a lower voltage.  Did any one else have a D2607 out of a Fuji camera?

[conradelektro]

Update on the wet paper towel (look at my last post four posts up):

I had some success replacing the wet paper towel (terminating the bifilar coil on the base of the transistor) with a resistor:

25 Volt , 200 K  --> power consumption about 20 mA (runs about 60 seconds when switched off)

25 Volt , 100 K  --> power consumption about 40 mA (runs about 30 seconds when switched off)

12,5 Volt, 200 K  --> power consumption about 10 mA (runs about 30 seconds when switched off)

12,5 Volt, 50 K --> power consumption about 40 mA (runs about 10 seconds when switched off)

When the power supply is switched off the brightness of the lamp decreases slowly till it goes out completely.


@ LaserSaber:

Did you ever try a resistor around 100 K instead of the four 1N60 diodes to terminate the bifilar coil (on the base of the Transistor)?


@ slayer007:

The number of turns (9 to 12) and the thickness of the wire (thicker is better) for the pancake coil seem to be very critical in a Slayer circuit. I still have not got an optimal pancake coil. Winding a 2.5 mm2 plastic insulated wire (normally used for wall sockets in a 220 Volt installation) in a loose spiral (about 9 to 12 turns) around the tower seems to work equally well.


Greetings, Conrad

[TinselKoala]

I am in general pleased with the progress being made in this thread. Keep up the good work ! We are all learning a lot, I hope.

The reason the MOSFET works well in this circuit is that it has a faster switching time and a lower on-state resistance than the stock transistor. It's more expensive though. There is a small cheap MOSFET that might work well in the circuit, the 2n7000. You will need a resistor in series with the gate, start at 10K and work down until the mosfet switches nicely. This might be the reason for the failure of the IRF640, if you didn't use a gate resistor; if they see a voltage spike on the gate they can fail easily. It's possible that the smaller cap delivered its pulse more quickly and caused an inductive spike to hit the gate, whereas the larger cap with the same or even more charge on it might have made a slower pulse hence less voltage in the spike, so the mosfet survived. Also, the gate can be protected by a reverse-biased Zener that will shunt a spike to ground (the mosfet source pin).

The pancake coil is a really good place to use the bifilar geometry that Tesla patented in #512,340. I've got some vids where I compare the performance of a Tesla bifilar pancake with a normally-wound spiral pancake using the same wire and the difference is obvious. The interturn capacitance of the bifilar is much higher and so the coil stores more energy, partitioning it into the magnetic and electrical fields around the coil.
I think this makes the square-wave response of the coil faster, which in turn helps the induction in any tuned secondary nearby.

The wet paper towel is a neat idea. I think it's sort of a nonlinear semiconductor element, functioning as a diode/resistor. It might be interesting to stick another lead in there and see if you can get some transistor action out of it !!