Wind Horn

Project Number: 61

Description: Build the circuit shown. Set the meter to the 5V setting. Blow on the fan or place it in a strong wind (either outside or near an electric fan). The meter measures how much your "windmill" produces, and the horn (W1) makes noise from the voltage.

Snappy: The electricity produced by the windmill motor is constantly changing, due to the mechanical design of the motor and the variations in the wind speed. The horn needs a steady voltage to work properly, so the 470uF capacitor (C5) is used. The capacitor stores a small amount of electricity and then releases it as needed to steady the voltage.