The red and yellow
LEDs (D1 & D5) are
used here to keep the
different power sources
from interfering with
each other, by
controlling the direction
electricity flows.
Build the circuit shown. Set the
meter to the 5V setting. The
meter measures the voltage
produced by the windmill, solar
cell, and hand crank, which are
connected to work together.
You can change the meter setting
to 50mA, to measure the current
produced.