Nodal Analysis Lab

Name ______Section ______

Prelab (Must be completed before lab.)

Nodal analysis is a method of solving for the node voltages in a circuit. A node voltage is the voltage of a node with respect to ground. In other words, it is the voltage between that node and ground. Nodal analysis can be used even when all other circuit solution methods will not work. Once node voltages are found, the voltages across each circuit element are found easily.

  1. Use nodal analysis to calculate the node voltages V1 and V2 in Figure 1. Record to datasheet.
  2. Use nodal analysis to calculate the node voltages V1, V2, and V3 in Figure 2. Record to datasheet.
  3. Use a PSPICEsimulation to find the node voltages V1 and V2 in Figure 1. Include a printoff of your simulation circuit. Record values to datasheet.
  4. Use a PSPICE simulation to find the node voltages V1, V2, and V3 in Figure 2. Include a printoff of your simulation circuit. Record values to datasheet.
  5. Compare your simulation results with your calculated values for both circuits.


Figure 1


Figure 2

Lab Session A

Measure the actual values for the resistors, and record them in the Data Sheet.

Use these values to calculate the nodal voltages V1 and V2. Use the Multimeter to measure V1 and V2 for this circuit.

Compare your measured values with your calculated values. Explain any discrepancies.

Use your measured node voltages to calculate the voltage drops across each resistor. See Figure 3.

Figure 3

Measure the actual values for the resistors for the circuit of Figure 2, and use these to calculate the nodal voltages. Use the Multimeter to measure V1, V2 and V3 for this circuit.

Compare your measured values with your calculated values. Explain any discrepancies.

Calculate the resistor voltage drops using the measured nodal voltages. See Figure 4.


Figure 4

Part B

Now, we will measure the node voltages, using the superposition principle. Zero the 8V power supply by setting it to 0V. Measure the voltages V1’, V2’ and V3’ in Figure 5 and record these into the data sheet.


Figure 5

Now, measure the voltages V1”, V2” and V3” in Figure 6.


Figure 6

The superposition principle states that the system response to all sources can be determined by summing the systems response to each source acting alone, with all other sources “zeroed.” This strategy only works for linear systems. Calculate the node voltages V1, V2, V3, by zeroing all but one source and calculating V1, V2, and V3. Repeat this process until all sources have had been accounted for and then sum each response. Remember that you must be consistent in your choices of polarity.

Compare the superposition results to the measurement results. Is there any difference?

Post lab

  1. Can these circuits be solved by other methods than nodal analysis?
  2. What was the easiest/hardest part of this lab?

Hand in:

  • Datasheet
  • Prelab calculations
  • Prelab simulations
  • Lab calculations
  • Answered questions from prelab, lab and postlab.
  • NO LAB REPORT required for this lab.

Datasheet: Nodal Analysis Lab

Name: ______Section: ______

Prelab

Fig 1 Calculated: V1 ______V2 ______

Fig 2 Calculated: V1 ______V2 ______V3 ______

Fig 1 Simulated: V1 ______V2 ______

Fig 2 Simulated: V1 ______V2 ______V3 ______

Lab Session A

Actual Resistor Resistor voltages:
Values:
R1:______VR1:______
R2:______VR2:______
R3:______VR3:______
R4:______VR4:______
R5:______VR5:______/ Calculated node voltages:
V1: ______
V2: ______
Measured node voltages:
V1: ______
V2: ______

Lab Session B

Actual Resistor Resistor voltages:
Values:
R1:______VR1:______
R2:______VR2:______
R3:______VR3:______
R4:______VR4:______
R5:______VR5:______
R6:______VR6:______/ Calculated node voltages:
V1: ______V2:______V3: ______
Measured node voltages:
V1: ______V2: ______V3: ______
Superposition:
V1’: ______V2’: ______V3’: ______
V1”: ______V2”: ______V3”: ______
V1: ______V2: ______V3: ______