Electrical Engineering: Thevenin's Theorem Lab Report, Circuit Design

This lab report details an experiment designed to verify Thevenin's theorem and the maximum power transfer theorem. The report begins with an overview of the objectives, which include understanding and applying Thevenin's theorem and constructing an equivalent circuit. The experiment involved calculating and measuring the Thevenin voltage (VTH) and resistance (RTH) of a given circuit. A breadboard was used to construct the circuit and measure the current, voltage, and resistance values. The report describes the procedure, including the use of a potentiometer to vary the load resistance and measure the corresponding voltage and current values. The results include the calculated and measured values of VTH, RTH, and the voltage and current across a load resistor. The maximum power transfer theorem was verified by varying the load resistance and recording the power dissipated. The conclusion confirms the validity of Thevenin's theorem and the maximum power transfer theorem, indicating that maximum power transfer occurs when the load resistance is equal to the Thevenin resistance. This assignment is a valuable resource for students studying electrical engineering and circuit analysis.

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Lab Report 4: Thevenin’s Theorem
Aims and objectives
1. To familiarize with the theory of the application of Thevenin’s theorem
2. To find the Thevenin’s equivalent of a circuit
3. To construct the calculated Thevenin’s equivalent circuit
4. To measure the operating parameters of the constructed circuit
5. To perform a comparison of the measured and calculated values
Apparatus used
1. Power supply
2. Bread board
3. Multimeter
4. Potentiometer
5. Connecting wires
6. Resistors
Procedure
The Thevenin voltage VTH and the Thevenin resistance RTH for the circuit provided in the
laboratory manual were calculated and recorded. A circuit with these values was then
constructed on the bread board. The current I4, voltage V4 and the Thevenin resistance were
then measured. Using the Thevenin equivalent circuit and a potentiometer, different voltage
and currents were measured and recorded by varying the potentiometer. This was done to
verify the maximum power transfer theorem.
Figures used

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Results and discussion
Part A:
Using the circuit provided in the laboratory manual and the given resistances, the values
shown in the table below were calculated,
The RTH and VTH values obtained were then used to construct the circuit. The voltage across
points a and b was measured and recorded with the circuit open. VTH was about half of the
supply voltage due to the drop in the RTH. The voltage source was then cut-off and RTH
measured. The readings of VTH and RTH were then used to construct a new circuit. A 330 ohm
resistor was then inserted between points a and b. The voltage across it and the current
through it were read and recorded in the table below.
The next part of the exercise involved verifying the theorem for maximum power transfer. A
potentiometer was used as the load. It was varied to obtain a total of 8 different values of
resistance (4 < RRH, 4 > RRH and one value equal to RRH). For each value of resistance, the
corresponding values of voltage and current were recorded. These values were then used to
calculate the dissipated power. The results are recorded below.

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Conclusion
Thevenin’s theorem was verified both theoretically and practically. Besides, the theorem for
maximum power transfer was also confirmed. It was observed that, the maximum power
transfer occurred when the load resistance was almost the same as the circuit’s Thevenin
resistance.