How to Build a Simple DC Generator

Electricity is generated by passing a conducting material through a magnetic field, causing movement of electrons.

A simple DC generator produces electricity by passing a conductive material through a magnetic field. This causes the electrons in the material to move, which creates an electric charge. By rotating copper wire inside a field created by two bar magnets, you can build a simple DC generator at home.

Things You'll Need

• 1 foot of insulated copper wire
• 1 nonconducting rod (wood or plastic)
• 2 2-inch bar magnets
• 3-by-14-inch cardboard strip
• 2-inch strip of aluminum foil
• Scissors
• Double-sided tape

Instructions

1. Fold the cardboard so it forms four sides of a rectangular box, the length of which must be shorter than the length of your nonconducting rod. Ensure the box is wide enough to fit both magnets plus the rod and several turns of copper wire. Fix the magnets to the inside of the box with the tape, so one is north and one is south. Pierce holes for the rod to pass through.

2. Slide the rod inside the box. Measure out 2 inches of copper wire and allow this to hang free while you coil the rest around the rod. Leave at least 2 inches of the copper wire free after coiling it. Pass both free ends of the copper wire out of the box, along the rod and out through the hole you made earlier.

3. Strip the insulation from the final inch of both free ends of the copper wire. Wrap the double-sided tape around the end of the rod where the wires are and remove the cover so both sides of the tape are sticky. Fix the uninsulated portion of the wires to the sticky tape on the rod.

4. Measure out enough aluminum to wrap around the end of the rod over the top of the wires. Cut this strip in half and trim both ends of each half so they will not touch when wrapped around the rod. Fix one strip to the rod over the double-sided tape and one end of of the stripped copper wire. Fix the other strip over the other stripped copper wire and double-sided tape.

Tips & Warnings

• The generator creates electricity when it is in motion and therefore requires some mechanism for spinning the rod. The spinning moves the conductive copper wire through the magnetic field to generate electricity. This can be done by hand if a handle is attached, or the generator can be hooked up to something that is turning, in the same way as a dynamo on a bicycle is used to generate power from the spinning wheels.

• Ensure the two strips of aluminum do not touch or the generator will not produce DC electricity. The aluminum forms the "split ring" system that prevents the flow of electricity from the generator changing direction. If the generator produced continuous electricity by having a full ring, it would continuously change polarity, becoming an AC generator.

References

• James E Koehler: Electromagnetism and Generators