Joule Thief

[jeanna]

@Bill,

The reason I got that 15 watt fluro tube was to see how it would light up from my wimhurst machine.

It was not impressive and it was tricky to hold the bulb and turn the wheel. But it did work and proved the concept.

It seems to me that the continuous nature of the high voltage spark is what would be creating this light in your tubes.

I may be repeating what freezer just said, but, the length of the spark will tell you the voltage.

If the spark comes off a small rod and is 1/3 inch it is about 30kv. (ref = ADMoore)

I guess your meter won't be reading that!.

Oh yeah, I was having fun sparking the flash last year and I ended up burning a small hole in my tablecloth and leaving about a 1/2 inch black mark on the table. So, maybe I was getting almost 40kv. (hmm maybe this is what I need for my HHO torch!!!!)

More mysteries continue. Lots to think about.

@xee2, so, I guess the little torroid is a perfectly balanced joule thief, like a filter transformer, whereas the flash is connected off center, so to speak and so it is really 2 transformers each making more volts from fewer. (or reverse)

@IST, I am not sure I am following you. could you please try again. I am way behind you on this and I think you were replying in a way to my question about how the 2 joule thief's relate to each other.?

Well, I guess I will glue the gasket back onto my car door today    and buy a fuji tomorrow.

Thanks all for your help. More Q's are sure to follow!

jeanna

[Pirate88179]

Some Christmas Pictures for all:

Fuji board circuit running 200 leds on my Christmas Tree all from single AA battery!!!!  In the bottom photo you can see my color organ (the plastic clear box on the lower right) and the fuji circuit. (bottom left)  Color organ and everything else is unplugged.  All I did was use a red and a blue jumper wire to go to the male plug ends of the two LED strings. (100 leds each)

Bill

[Pirate88179]

More 200 LED shots....

Bill

[Pirate88179]

The top one is a little blurry as my shutter stays open without the flash...hard to keep from moving.  The bottom photo is with the flash.

I am glad I tried this!!!  These are really bright, hard to tell in the shots but, brighter than when hooked to my color organ and plugged into the wall with loud music playing.  I think this could drive 300 easily.

Next, I am going to try to run my heat pump from this circuit. (Just kidding)

Bill

[xee2]

@ Pirate88179 


Easiest way to measure peak open circuit output voltage is to put a diode and cap in series in place of the tube. Let the cap charge up and measure its voltage with DVM. This will be peak DC voltage. Should be about 300 volts peak DC. Then double that voltage to get peak-to-peak  AC voltage. Should be about 600 - 700 volts peak-to-peak  AC. These are just guesses, actual voltages may be higher.