Maximum Power transfer

ELECTRICAL AND ELECTRONICS ENGINEERING
LAB INVESTIGATION II (EEE3411)

"MAXIMUM POWER TRANSFER"


Student Name: Mahroo Uris
Student ID: SCM-030782
Lecturer: Mr. Chris
Date of Experiment: 24th September 2015
Date of Submission: 15th October 2015



-Introduction:
Maximum power transfer theorem states that, to obtain maximum external power from the source with a finite internal resistance, the resistance of the load must be equal to the resistance of the source as viewed from its output terminal.
Load Resistance (RL) = Internal Resistance (Ri)
The theorem results in maximum power not maximum efficiency.
Maximum power from the experiment can be determined by the following equation where V is the DC voltage supply.
Pmax = V2 / 4RL


-Objective:
The objective of this experiment is to verify the maximum power transfer theorem through an electrical circuit.


-Equipments:
Voltage supply.
Constant RI.
Different values of RL.
Ammeter.
Breadboard.


-Circuit Diagram:




-Experimental Procedure:
Circuit was connected as shown in the diagram above.
The readings of voltmeter and ammeter for different values of RL (variable) were taken.
Verified that the power is maximum when RL = Ri.



-Results and Analysis:
The following table below shows the current produced when different values of RL resistors were used and power dissipated in the load. Voltage used in the circuit is constant which is equal to 5V and internal resistance Ri is 5.1k remained constant throughout the experiment.

SR.No
RL(k )
IL(mA)
Power: I2x RL(mW)
1.
1
0.820
0.672
2.
2
0.704
0.991
3.
3
0.617
1.142
4.
3.9
0.556
1.206
5.
5.1
0.490
1.225
6.
6.8
0.420
1.199
7.
8.2
0.376
1.159
8.
10
0.331
1.096

-Theory Calculation:
To calculate power in the equation:
Power = I2 x RL
P = (0.704 X 10-3)2 x (2 x103)
P= 9.91 x 10-4 0.991mW

-Discussion:

In this experiment, the main objective was to verify maximum power transfer theorem. Maximum power theorem states that the load resistance will abstract maximum power from the network when the load resistance is equal to the internal resistance. From the experiment conducted above. We used different values of resister RL (variable) and noted down the ammeter reading and calculated the power dissipated in the load. The voltage supply and the internal resistance Ri as kept constant throughout the experiment.
According to the result and analysis we got to know that when the resistance value RL was to increase, the reading on the ammeter was getting decreased. We calculated the power using the formula mentioned and achieved maximum power when the internal resistance was equal to load resistance.

-Conclusion:

As per the results and analysis, the objective of this experiment was achieved. Maximum power transfer theorem is verified as when the load resistance is equal to internal resistance the maximum power is dissipated. Hence the theorem is proved.

-References:

Thomas L, Floyd, 2010, principles of Electric Circuits, 9th Edition, Pearson Prentice Hall.