Joule Thief

[xee2]

In order to get 100uF across the battery rails I put 2 47F in series.

Two 47 uF in series is 23 uF twice the voltage. Two 47 uF in parallel is 94 uF at half voltage.

The battery cap generally is not needed unless battery drain is about 1 amp.

[jeanna]

Two 47 uF in series is 23 uF twice the voltage. Two 47 uF in parallel is 94 uF at half voltage.

The battery cap generally is not needed unless battery drain is about 1 amp.

I think I see. I did it backwards for getting more F. but...

Isn't it the need for more voltage to start up a fluoro that is the reason for the ballast etc?
I assumed that this was the reason Hazens used the 100uF cap in this spot; and that is why I added them in series.

This is a 2500maH battery, so I guess it will run for a bit.

What would a trigger circuit be?
Would it be something like these caps with a push button?

thank you,

jeanna

[xee2]

@ jeanna

I think your guess that the voltage was marginal was probably correct. I still recommend adding more turns to the pickup coil. I think your problems will go away if you add at least another 100 turns.

[TheNOP]

Not sure if it will work in this setup but look at a zenier diode. They dont conduct until the rated voltage is reached. In this case it will reach it and dump and fall below again. Getting one for the voltage you need may be a pain. But then you might use a resistor in series with it to drop the voltage down.  Just that the spikes may cause havoc with it just not sure.

a zener diode does not work quite like you describe it.

i posted an experiment with a 1N227 14.5 volts / 400 mW a while back.

they start conducting before their rated voltage.
the more the voltage is high, the more they conduct.

zener diodes must not be confused with avalanche diodes.
finding an avalanche diode for the specific voltage you need might be difficule as they are usually used to supress transient surges.

[TheNOP]

I got it to turn on by having the magnets in place and plugging the battery in then holding one hand on the tube and the other hand on the magnet, until it lit and the light spread a bit, then I moved my hand up the tube to the other end and slowly let go; first the light then the magnet.

a magnet, hummm...

bring a carpet near where you experiment.
rub your feet on it and touch the neon tube while your jt is running and when your tube does not start.

my opignion is that the magnet is not having the effect that are attributed to them while still having an effect.
the effect i am thinking of is more about static charges then magnetic.

i am not saying that the mag field of a magnet as no effect on the neons.
i am questionning myself since i know the same effect can be obtain with something else then a magnet.
a piece of plastic, even a sheet of paper, can do the same.

the carpet experiment can be done in the dark with not power apply to the tube.
it will glow while you rub.
and it will even glow for a bit longer, after you stop rubbing.