Maximum Power Transfer

Purpose: To analyze power transferred by a circuit and see the relation to maximum power.

Introduction:

We will set up the following simplified circuit.

Experiment:

We use DMMs to measure the voltage and resistance to find power.

We now set up the original circuit and measure the current and voltage with Logger Pro.

Data:

Measured V0 (Volt) Measured Rx (ohm) Calc. P0 (Watt)
0 13.                         5                            0.0000E+00
0.16                          330                        7.7576E-05
0.34                          691                        1.6729E-04
0.51                          1126                      2.3099E-04
0.68                          1707                      2.7088E-04
0.85                          2390                      3.0230E-04
1.02                          3020                      3.4450E-04
1.19                          5680                      2.4931E-04
1.36                          2280                      8.1123E-04
1.53                          2780                      8.4205E-04
1.7                            3270                      8.8379E-04
1.87                          3800                      9.2024E-04
2.04                          4440                      9.3730E-04
2.21                          5120                      9.5393E-04
2.38                          5940                      9.5360E-04
2.54                          6850                      9.4184E-04

The graphs of current, voltage and power are shown below.

 The maximum power output happens around 5.2 k Ohms. This is a 7.1% error from the theoretical value of 5600 ohms.
  Logger Pro had a lot of noise in the data but there was a visible trend and we were able to get a decent power graph. In this case it was better to do the data recording manually.