How to Build a DC Generator

Easily build a kid's DC generator.
••• blue bulb image by Rikmo from

Build a DC generator from scratch. This type of motor creates a current of electricity that travels in one direction (direct current) that is suitable for charging car batteries or running DC current devices. It is the first basic generator created by Edison until Tesla came along with his AC generator (see our AC generator instructions in other articles).

    Make a cardboard box that is 2 inches square. Embed magnets into the box at opposite sides so that they have opposite polls facing each other. Choose one of the walls between the two walls containing the magnets to remove for access. Remove this wall and the wall opposite from it, leaving the corners in place for support.

    Make a small box of cardboard big enough to fit into the space between the two magnets with room to spare on either side (1.5 inches square). Stick a pen through this smaller box in the exact center. Wrap copper wire around the box so that it is not concentric to the pen stuck into it. As the wire goes around the box, it should pass over the two faces impaled by the pen. Make sure that enough wire comes out of the coil at both ends of the wire to touch one end (the same end) of the pen.

    Puncture a hole in the center of each side of the big box that is still untouched. The holes need to be big enough for the pen to rest in loosely. Remove the pen from the small box. Put the smaller box into the bigger box so that the pen holes of each box line up with each other. Insert the pen through the holes to hold the smaller box inside the bigger box so that it can spin freely without the two boxes touching. Glue the smaller box in place on the pen. Do not glue the pen to the big box.

    Around the axle (the pen), wrap a small piece of two sided tape. Strip the tips of the wires and lay them flat in opposite sides of the tape on the axle. Do this so that the wire tips are parallel to the ground when the wires wrapped around the small box are at their closest point to the magnets. Cut a strip of aluminum from a can that is big enough to cover the two sides tape strip on the axle. Cut this piece in half the short way and trim off 3mm from each side of the cut. Sand down both sides of the strip of can so that the metal is exposed. With the small box in the same position mentioned earlier, place the two pieces of metal so that one is facing left while the other one is facing right with the inner box in the same position mentioned earlier.

    Cut two more strips of metal from the can that are 3 inches long and as wide as the previous strips. Sand both sides of the new strips. Cut two 6-inch pieces of wire and strip both ends (of both wires). Tape one end of each wire to a different 3-inch strip. Glue down the two 3-inch strips to the base of the cardboard so that when the inner box is in the position mentioned earlier, the 3-inch strips contact two different strips on the pen/axle.

    Hook up the free ends of the wires to an ammeter and spin the inner box to make a DC current. Compare this current to the AC current in our other article on making an AC generator (the low-voltage one, for safety please).

    Things You'll Need

    • Magnets (neodymium preferred)
    • Cardboard
    • Copper wire (1 spool)
    • Pop can
    • Pen
    • Hot glue gun and glue stick
    • Sand paper


    • To make the pen spin more freely, split small sections of straws and glue them in the cardboard to reduce friction.


    • Do not make this generator on a bigger scale than is intended here. The amount of wraps around the inner box should be about 100, so it should be safe if the electricity is not stored up. Do not use this generator to charge anything unless you know what you are doing.

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