If the light bulb won't light, usually
it's because the wrong bulb was used. Follow instructions.
If you changed the magnets, it won't work. So
don't use different magnets. If you used a different bulb, it won't work.
Use the parts in the partslist, don't make changes. If you're not using
#30 enamel varnish-coated wire, then it won't work. So don't use
Don't use different parts. Before testing anything else, ask yourself if
you used the parts in the parts list. If you used different parts, the
generator will fail. Notice: it's very important that you use the parts
listed, and don't use substitutes. And have I mentioned, DON'T
USE FREAKIN' DIFFERENT PARTS! What, do you WANT it to fail? :)
SPIN IT FAST, IN THE DARK
Sometimes your generator is working
you're not spinning it fast enough. Flick the nail between finger and
thumb, like when you snap your fingers ...or like when you spin a top at
maximum speed. Make your magnets really whiz like
a blur. (If they grind against the cardboard, it won't work.) Or perhaps
the dim glow of the light
bulb is being missed in a brightly lit room. So, go into semi-darkness.
Then spin that thing REALLY FAST. Try cranking it with an old-fashioned
hand-crank drill (electric drills don't go very fast). Or try sticking a
little wheel on your nail, then rub the wheel on the spinning tire of
an upside-down bicycle (don't go too fast or the bulb will burn out.)
ADD LOTS MORE WIRE
If your coil has more than 250 turns of #30 wire, then the magnet doesn't
need to spin so fast. And the bulb lights
brighter. The #30 spool of thin red Radio Shack wire is 200 feet long,
which gives about 250 turns. If you could wind more turns on your coil,
then your bulb would light up at lower magnet speed. Buy two kits of
wire from Radio Shack, then use both spools of the
thinnest type (red #30.)
Scrape the red plastic coating off all the wire ends. Then twist the
end of the new spool to the end of the old one. This creates a single
wire. Be sure to wind the extra wire in the same
direction as before. Even better, buy a few "open frame solenoids" from
mail order, or buy larger spools of wire. It's lots cheaper than Radio
If the wire is too thin, the resistance is too high and the bulb will
be very dim. If the wire is too thick (or if it has thick insulation,)
then 250 turns will be the size of a grapefruit, and the outer turns will
be too far from the magnets. Better source of wire:
buy a large "Solenoid"
from a mail order company, then use Vice-grip pliers to pry open the metal
bracket. Remove the the big coil, peel off the tape, and wind it on your
generator. Try this one:
12V solenoid $3.75
DON'T USE OTHER MAGNETS
Use the large 2-inch rectangular block magnets sold by Radio Shack and
#64-1899. Or try
Edu. Innovations, or CMS.
They cost about $2 each, and have no holes through the center. Don't use
the smaller 1 inch Radio Shack magnets. Most other magnets are too weak
and will not work unless you spin the magnets incredibly fast, at
thousands of RPM (revolutions per minute.)
USING SMALLER MAGNETS
If you can't wait for mail-order of
the correct magnets, instead you can use twenty of the 1" magnets 64-1879.
Glue them together to form two large magnets. Here's how I did it.
First I formed four larger magnets: I glued twenty magnets in four
separate stacks of five magnets each. I used 5-minute epoxy. Before the
glue hardens, adjust the magnets so the sides of each small stack are
flat, and wipe off the excess epoxy. (To make the sides flat, I laid each
stack down on aluminum foil, pressed them down to align the magnets, then
peeled off the foil when the glue was hard.) Next, glue two of these
5-magnet stacks together side by side so the stacks are repelling each
other, then hold them together until the glue hardens. That way the N
pole of one stack is near the N pole of the other, and S is near S. Do
the same with the other two stacks. This gives you two large magnets,
each made up of ten small ones. Each magnet should have two holes on each
flat pole face. Let the magnets clamp themselves on either side of your
nail as usual. These aren't as powerful as the four "high energy" ceramic
magnets, so you'll need twice as much wire for your
DON'T USE A DIFFERENT BULB
This generator cannot power a normal
flashlight bulb, it needs the
special 25-milliamp, 1.5-volt bulb sold by
Radio Shack. Also try using a red LED (but you must spin magnets much
faster, like twenty turns per second. Or use way more turns of wire.)
Don't use a normal flashlight bulb, since that kind of bulb
requires way more energy before it starts to glow. If you simply cannot
find the Radio Shack 25mA bulb, you can use a 1.5V 40mA bulb, but add
twice as much magnet wire to your coil (buy two of those kits of magnet
wire.) The generator needs way more than 250 turns wrapped
around it. Five hundred turns is better, that way you won't have
to spin the magnets so fast. If you use a red LED, then use three times
more turns of wire. The special light bulb needs one half volt, while Red
LEDs light up at 1.7volts.
STACK THE MAGNETS SO THEY STRONGLY ATTRACT
Make sure the magnets are
stacked to create two strong poles, otherwise the generator won't work.
Do this: stack up all
four magnets so their widest faces are clinging together. Then jam the
nail through the crack in the middle of the stack. Then take this
apart, and re-assemble it inside the generator in the same way.
CLEAN THE WIRE ENDS THOROUGHLY
If the generator refuses to work, inspect the spot where the wires twist
together. The generator coil has a very thin red plastic coating, and you
must clean ALL of this coating off the wire ends before twisting them to
the light bulb wires. Also, the tips of the light bulb wires must be
stripped clean of plastic. The metal wires must touch together.
If there is plastic between the metal of the generator wire and the light
bulb wire, the circuit will be "open" and no charge will flow.
Be sure to follow the instructions and diagrams. You MUST wind the coil
so the coil goes across the side of the box which has the nail hole. If
you wind it so no coil is crossing the nail-hole side of the box, then the
magnetic fields won't cut across the wires, and no electric voltage will
Also, don't wind the coil over the open end of the box, otherwise you
won't be able to get your fingers inside to make changes to the
If you cannot spin the magnets fast enough with your fingers, try a
"twist drill" or hand-crank drill. Clamp the nail in the end of
the drill and spin the magnets as fast as you can. An electric
drill may work too, but most electric drills don't move as fast as
the hand-cranked type. Also try Arvind Gupta's trick: wind about
300cm of string around the nail, then pull it hard to spin the
[WARNING, SOME AC VOLTMETERS WON'T WORK AT 4 CYCLES PER SECOND,
AND ARE DESIGNED ONLY TO MEASURE 50Hz or 60Hz.]
If you have a
DMM voltmeter, set it to measure two
volts AC, then connect it to the generator wires and spin the generator.
The light bulb needs a bit more than 0.50 volts AC in order to light
dimly. At 1.0V it lights brightly. If your generator's voltage is lower
than 0.5V, you need to spin it much faster, or you need strong magnets, or
you need to add lots more turns of wire.
DON'T SUBSTITUTE THE MAGNETS OR THE BULB WITH A DIFFERENT
needs strong magnets and a low-voltage, low-current incandescent bulb.
If your generator doesn't work, check the parts again and make sure you
have the right type of magnets and the right type of light bulb. Don't
use fewer magnets. Weaker magnets may work in theory, but you won't be
able to spin them fast enough by hand, and a high speed motor will be
required in order to spin them. Don't use an LED. A red LED could work
in theory, but you need at least 1-1/2 volts to barely light one up (the
green or blue kind need even higher volts.) The light bulb is better
because it lights up at less than 1/2 volt. (If you really must light up
an LED, use the red kind, and also add about three more spools of #30 wire
to your generator coil.)
Perhaps your luck is bad and you got a dead light bulb. To test it, get
any new, fresh 1.5V battery (the size doesn't matter.) Take the bulb off
the generator, then touch one wire form the bulb to the top of the battery
and one wire to the bottom. The light bulb should light up brightly. If
it stays dark, the bulb is bad.
The generator can be improved by using more turns of wire. You used only
the spool of #30 wire. With more wire, the magnets don't have to spin as
fast to light the bulb. Connect the thinnest of the remaining spools of
wire to one end of the wire that's already wrapped, making sure to scrape
the wire ends totally clean before twisting them together. Make sure to
wind the extra wire in the same direction as the rest of the coil.
Or, if you want to light your light bulb REALLY bright, buy a second kit
of wire, hook the second #30 spool to the coil you have already made, then
wind all the wire onto the coil. Be sure to clean all the red plastic off
the ends of the extra wire that you've added.