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2. Next, attach a second 10 ohm resistor across the other set of OUTPUT terminals (red
and black) and verify a similar plot as shown below. Notice that the resistance reading is
5.7 ohms. This is consistent with the two 10 ohm resistors in parallel along with the 1
ohm sense resistor in series with them.
Figure 3.3 – 5 ohm Resistor Discharge Curve
Analysis:
As the two plots show, the fuel cell's voltage rapidly decreases with one 10 ohm resistor applied
and decreases even more rapidly as the second 10 ohm resistor is attached. Also, the formula
for Ohm's Law is obeyed, which is:
E = I*R
Where E = Voltage in Volts
With a single 10 ohm resistor applied as a load, the fuel cell attempts to supply current into it;
however, the supply of hydrogen that creates the voltage and current quickly begins to dissipate
under such a relatively heavy load. As such, the voltage (green line) and current (blue line)
decrease as the hydrogen is consumed.
Applying a second 10 ohm resistor in parallel with the first 10 ohm resistor creates even a heaver
load of 5 ohms as shown by the formula below:
I = Current in Amps
R = Resistance in Ohms
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