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Because the 1 ohm sense resistor on the circuit board is in series with the parallel resistors, the
resultant resistance should be 6.00 ohms. However, due to inaccuracies in the value of the
resistors (the actual resistance of each resistor in this particular experiment is less than 10 ohms
– your results may vary), the measured resistance on the computer display is 5.7 ohms.
This experiment points out how resistors in parallel generate more of an electrical load to the
power source as compared with just a single resistor of the same value.
You are encouraged to repeat this experiment and, this time, look more closely at the current and
power plots rather than the voltage plot. In order to this reduce the vertical setting so that the
current and power plots are better visible.
1 ohm
sense
resistor
10 ohm
Load
resistor
= 6 ohms total
10 ohm
Load
resistor
R1
R2
R
parallel
=
R1 x R2
R1 + R2
=
5 ohms
