# Lab 06: PSpice Analysis of DC Circuits

## Objectives

• Use PSpice Circuit Simulator to check laboratory circuits and homework problems.

## Background

A DC circuit is a circuit in which the voltages of all independent voltage sources and the currents of all independent current sources have constant values. All of the currents and voltages of a DC circuit, including mesh currents and node voltages, have constant values. PSpice can analyze a DC circuit to determine the values of the node voltages and also the values of the currents in voltage sources. PSpice uses the name “Bias Point” to describe this type of analysis. The name “Bias Point” refers to the role of DC analysis in the analysis of a transistor amplifier.)

In this lab, we consider four examples. The first example illustrates the analysis of circuits containing independent sources while the second is dependent sources. The third illustrates the use of PSpice to check the node or mesh equations of a circuit to verify that these equations are correct. The final example uses PSpice to compare two DC circuits.

## Procedure

1. Hand Calculations: Solve the circuit analysis problem by using KVL, KCL, and Thevenin's theorem.
2. Draw the Circuit Diagram: Describe the circuit using Schematics in the PSpice Capture. This description requires three activities:
1. Place the circuit components in the Schematics workspace.
2. Adjust the values of the circuit component parameters.
3. Wire the circuit to connect the circuit components and add a 0 Volt ground (referenced ground).
3. Simulation: Using PSpice to simulate the circuit.
4. Results: Display the results of the simulation.
5. Verify: Compare the simulation results with your calculations.
6. Report: Write the answer to the circuit analysis problem.

## Report

Turn in all PSpice circuits for each of the parts listed below:

• Exp #1: Determine the voltage V across the 6 Ω-resistor using simple circuit techniques and compare it to PSpice calculated value. How do they compare?
• Exp #2: Determine the voltage V across the 5 Ω-resistor and the current i through the 6 Ω-resistor using simple circuit techniques and compare it to PSpice calculated values. How do they compare?
• Exp #3: Use PSpice to determine the node voltages (Vb, Vc, Vd) and the mesh (or loop) currents (i1, i2, i3, i4). Substitute these values into the node equations and the mesh equations. Do the PSpice values satisfy these node and mesh equations?
• Exp #4: Use PSpice to determine that the controlling variables (ix, iy, Vz) and verify that the dependent source values are correct.