Windy Time

Project Number: 56

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. You may need to give the fan a push to get it started. The clock (T2) display should be on, and stay on for a while when the wind is not blowing. Together the "windmill" and the capacitor (C5) can run the clock using free, clean wind power. The red LED (D1) will not light.

Snappy: The 470uF capacitor can store a small amount of electricity. The clock needs very little electricity to operate, so the capacitor can run it for a while when the wind is not blowing. The red LED is like a one-way light, only allowing electricity to flow in one direction. Here it is used to prevent electricity stored in the capacitor from discharging through the motor when the wind is not blowing.