The National MagLab is funded by the National Science Foundation and the State of Florida.

# Pixii Machine

This “magneto-electric machine” was the first to turn motion into electricity.

In 1831, the great experimentalist Michael Faraday discovered that changes in a magnetic field could induce an electromotive force and current in a nearby circuit – a phenomenon known as electromagnetic induction.

French instrument maker Hippolyte Pixii harnessed these ideas in 1832 with the Pixii Machine. It was the first practical mechanical generator of electrical current. Whereas earlier instruments, such as Faraday’s Motor and Barlow’s Wheel, turned electricity into motion, the machine demonstrated here was the first to do the opposite— turn motion into electricity.

## Instructions

1. Take a look at how this device is set up. Notice at the top are two wire coils, connected in a circuit.
2. Observe a permanent magnet under the coils, with its opposing poles sticking up toward the coils.
3. Note how the magnet is on a base that can be rotated using the hand crank underneath.
4. Press on to start the crank and notice what happens
5. Due to electromagnetic induction, the rotating magnetic field causes a current to flow in the wires above it.
6. See the surges of electricity recorded by the galvanometer attached to the circuit.
7. Experiment with the crank speed, notice the difference in how more current is produced as the magnet turns faster.
8. Notice how the machine produces two surges of current for every full revolution of the magnet. Due to the spinning of the magnet, the alternating current flows for a moment in one direction, then reverses course. This is reflected in the galvanometer needle, which jumps in one direction, then the opposite.
9. To produce current in only one direction, click the DC button to create direct current, and observe the effect this has on the flow of current. Clicking on the DC button simulates activating a DC commutator. The commutator flips a switch momentarily once every revolution, in order to reverse the direction of the current. That way, the current generated by the motor always flows in the same direction.