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Hey Gang! I'm going to show you how to power this compact
fluorescent lightbulb off of batteries using a fairly simple
circuit, and with only a few parts.
The first step is to open up a compact fluorescent lightbulb.
Sometimes you can pry them open but most of the times you have to cut
them, being careful not to cut too deeply and damage anything inside.
Opening it up you'll either see some electronics, like this,
or just some thin wires, like this. In either case, cut the wires so that you
leave as long a length as possible going to the fluorescent light tubes.
Keep the part with the tubes and thin wires.
Don't worry, the tubes are sealed so no mercury will get out.
You don't need a lot of other parts. Two 1.5 volt AA batteries and
a battery holder. A switch, for convenience. A power transistor like
this 2N3055 transistor. A variable resistor, or potentiometer. Mine is
100 ohms, which is probably a little bigger than is needed, though
bigger will work too. A ferrite core. I salvaged mine from this piece of
hardware which I think was a power supply.
You'll also need wire, some for connecting it all together and some
for winding coils. One of the wires will need to very thin with thin
insulation, often called magnet wire. I got it in this package from
Radio Shack, but any electronics store will have it. More on that later.
And of course, you'll need a tube from a compact fluorescent lightbulb.
You can start with a working light or one that no longer works. The
tube is usually still okay either way.
And here's the circuit. In case you've heard of the joule thief
circuit, that's what this is. But, the LED is gone, and the small
transistor is upgraded to a power transistor like the 2N3055.
It's also handy to replace the fixed value resistor with a variable
resistor, or potentiometer. Also, an extra coil is wound on the ferrite
core and the compact fluorescent lightbulb is attached to that
coil. In this form it's popularly known as Jeanna's light.
It took some experimenting to find the right windings for the coil
that worked. But what worked for me was to wind 256 turns of 30 gauge
wire around first, being careful not to overlap the turns too much.
This is often called magnet wire and what's important here is that
the insulation on it is very thin, allowing you to put a lot of turns
on this small ferrite core. While there's still a gap of at least around
1/8 inch, or 2 millimeters, between where the two ends meet, stop. There's
going to be a high voltage between these two ends so you'll need
wire with thicker insulation where the two ends are close together.
At this point I taped the windings solidly to the core...
and then soldered wire with thicker insulation onto both ends.
Then I finished winding them both until they met and taped the ends
in place. I added a little more tape to flatten out
the surface and insulate more where the soldered ends were.
This is followed by 10 turns of 18 gauge, surrounding where the first
winding ended. Notice that this one has better insulation than just
enamel insulation too, again to avoid breakdown due to the high voltage.
I tried 7 turns first but the results weren't as good so don't be afraid
to do some experimenting. And lastly, 5 turns of 18 gauge, well insulated
wire are wound over top of that. They can all be wound in
the same direction.
Of course I first connected it all together with alligator clips
to get it working. These early tests used wires with thinner insulation for
the coils and worked until the high voltage damaged the insulation.
The coils with thicker insulation like I showed how to make don't
have that problem.
And then I started on a cleaner version. I found a pill bottle that would fit everything nicely.
I hot glued the potentiometer to the back of the battery holder,...
as well as the transistor, but while gripping the transistor with
a large metal object to absorb some of the heat. I taped the coil
to the holder's cover using aluminum tape, which can handle heat,...
and then screwed the holder closed.
Next I used hot water to remove the paper label from the bottle,...
and cut it in two. I made a hole in the pill bottle for the poteniometer's
*** to stick out. Then while I was at it, I also made a hole where
the switch would stick out. A quick check showed that it would all fit.
Next came soldering the wires in place. First up was this blue
coil, one end goes to the resistor and the other to the base pin of
the transistor, the one indicated with a B. Then I connected one end of the black coil
to the collector of the transistor. Be very careful which end you
connect. It has to be the end that corresponds to the end of the blue
wire that goes to the resistor. The collector is the transistor's
case. As you can see I'm connecting it using a small nut and bolt through
a hole in the transistor's case. And here it is done.
Next I soldered the battery negative wire, the black one, to the
other pin of the transistor, the emitter pin, indicated with the letter E.
Next up is to connect these two wires to this end of the switch.
I started by soldering one end of a red wire to the resistor. The
other wire is the remaining end of the black coil. I soldered that
red wire and that black wire to one leg of the switch.
I soldered the red battery positive wire to the other leg of the switch.
Finally, it was time to connect the fluorescent lightbulb tube
to this coil that has many, many turns.
Notice that there were two pairs of wires coming out of the tube.
Treat each pair as one wire, twist them together if you can.
It doesn't matter which end of which coil is soldered to which pair,
there's no polarity involved. Just solder on end of the coil to one
pair of wires and the other end of the coil to the other pair of wires.
And the wiring's all done, we're ready to close it up and test.
After closing it up with some clear packing tape, I give it a try.
It works great!
It was at this point that I noticed a certain similarity to a soda can.
So I cut open the top, ... and cut a slit down the side and part way
across the bottom. Next came holes for the switch, ... and the
potentiometer's ***. Time to insert it in the can, ... and to
bolt it in place. Last up was to seal it with some clear packing
tape. Done!
And what about in the dark? Here it is illuminating my office slash
storage room. You can see it's quite bright.
It's even bright enough to read by.
And here it is outdoors at night, in the rain, illuminating the
darkest place in our yard, my worm composting bin.
And after a long day building stuff, it's time to lie back and
relax with a good book, illuminated by the fruits of my labor, of course.
Well thanks for watching!
See my youtube channel, rimstarorg, for more videos like this.
That includes one explaining how the joule thief circuit works.
Another going step-by-step how to use this joule thief circuit,
one AA battery, and a breadboard, to light an LED. And for
variety, one on how to make a very simple AM radio transimitter.
And don't forget to subscribe if you like these videos, or give
a thumbs up, or leave a question or comment below.
See you in a bit!