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4. In the expanded view above, notice the change in current and power as the voltage
climbs to its stabilized level of 1.440 volts. In the very beginning of the plot (in the circle)
the current plot line (blue line) indicates an immediate rush of current from the wind
turbine into the fuel cell; however, since the voltage is so low, almost no power (red line)
is generated. Remember the formula for power is voltage (E) times current (I) …
P = E*I
…so if E (voltage) is low or zero, very little or no power (P) will be generated.
As the plot continues notice that the current, voltage and power all increase before
leveling off. In this screen capture the voltage is 1.445 volts, the current is 0.022 amps
(22 milliamps) and the power is 0.032 watts (32 milliwatts).
5. Now, disconnect the wind turbine red lead from the circuit board and notice that the
voltage dips slightly (circle). The wind turbine is completely out of the circuit at this point,
so the voltage is coming from the fuel cell load.
Figure 6.5 – Fuel cell voltage output
Analysis:
Although the WindCharge
tm
wind turbine can deliver the minimum amount of voltage to
decompose water, it is very limited in the amount of current that it can produce to do the task
quickly. As a result, the electrolysis process takes longer. However after a few minutes of
electrolysis the wind turbine does generate a small amount of hydrogen, which is evident in the
voltage displayed even after the wind turbine is disconnected from the circuit.
You are encouraged to repeat this experiment and, this time, allow the table fan to blow air for 15
minutes, or more. This should be enough time to fully inflate the hydrogen balloon. If this is done
the 10 ohm load should not deplete the hydrogen so quickly allowing the voltage and current to
