Task 1: Circuit Theory [P1]

Theory

• Describe in details the Thévenin's and Norton's theorems.
• Compare and contrast the above theorems.

Experiment

• Experimentally determine the Thevenin and Norton equivalent circuits by measuring the open circuit voltage and short circuit currents of the circuit shown below. Use the principle of superposition along with Thenvenin's and Norton's theorems to reduce complex circuits to simple voltage and current source models. Compute the theoretical equivalents and compare them to the experimental equivalents.

• Construct the circuit shown above and measure the voltage, V_ab, across the 10 kΩ resistor. Record the value of V_ab.
• Remove the 10 kΩ resistor from the circuit and measure the Thevenin's open circuit voltage, V_oc, for the remaining circuit.
• Measure the short circuit current, Isc. Record the value in a table
• From the measurements made above, calculate the Thevenin'sand
• Norton's equivalent resistance for the circuit. Record these values.
• Calculate the theoretical values of R_TH, R_N, V_oc, and Isc for the circuit above. Record the computed values in Table
• Using the Thevenin's equivalent circuit, compute the value of V_ab with the 10 kΩ resistor attached to points a-b.
• Using the Norton's equivalent circuit, compute the value of V_ab with the 10 kΩ resistor attached to points a-b.

Report

• Include drawings of the Thevenin and Norton equivalent circuits with all values labelled.
• Compare the theoretical values to the measured values by computing the percentage error between the theoretical and measured values.
• Discuss the sources of the error.

Nodal and Mesh Analysis

• Determine the voltage V₁ and V₂ shown in the diagram below using node analysis.

• Describe the circuit below using Mesh analysis.

Task 2: Investigate complex waves

• In Figure 1 the voltage across the resistor VR is 100V and the voltage across the capacitor VC is145V. Sketch the phase diagram and hence calculate the value of V and the phase angle.
• A tuned parallel circuit comprises a 300μH inductor connected with a 2 kΩ resistor and a 10μF capacitor. Determine the frequency of resonance and the current in each component at resonance if the supply voltage is 4V.
• 4. Describe the term power factor.
• 5. A transformer has a turns ratio of 12:1 and is operated from the mains, it supplies a 5Ω load.Sketch the circuit diagram and determine the primary and secondary voltages and currents.
• 6. Often circuits produce complex waveforms; show how these can be made up of different sinusoidal signals. Give typical examples of these waveforms.