(i)
Part II - Allegro
1.
Introduction to OrCad PCB Editor
OrCad PCB Editor 15.7 .................................................................................................... 34
(ii)
1: Introduction to PSpice
In the past, students traditionally verified their laboratory electronic circuits by building them on breadboards and measuring the various nodes with the appropriate laboratory equipment. By using a computer simulation program, such as PSpice, students can obtain results before they come to lab. Hence the laboratory experiments become reinforcement to the subject matter at hand. The use of a computer simulation program allows the student to easily subject the circuit to various stimuli (such as input signals and power supply variations) and to see the results in either a tabular format or plotted out graphically using PSpice's post processor called Probe.
An Outline of PSpice
PSpice simulates the behavior of electronic circuits on a digital computer and tries to emulate both the signal generators and measurement equipment such as multimeters, oscilloscopes, curve tracers, and frequency spectrum analyzers.
Types of Analysis Performed by PSpice
PSpice is a general-purpose circuit simulator capable of performing four main types of analysis: Bias Point, DC Sweep, AC Sweep/Noise, and Time Domain (transient). Bias Point The Bias Point analysis is the starting point for all analysis. In this mode, the simulator calculates the DC operating point of the circuit. Options include calculating the detailed bias points for all nonlinear controlled sources and semiconductors (.OP), performing sensitivity analysis (.SENS), and calculating the small signal DC gain. (.TF) DC Sweep The DC Sweep analysis varies a voltage source over a range of voltages in an assigned number of increments in a linear or logarithmic fashion. AC Sweep/Noise The AC Sweep/Noise analysis varies the operating frequency in a linear or logarithmic manner. It linearizes the circuit around the DC operating point and then calculates the network variables as functions of frequency. The start and stop frequencies as well as the number of points can be assigned. Spice will compute the effective noise voltage spectral density that appears at the Output Voltage node because of internal noise sources (.NOISE). In this analysis the detailed bias points for all non-linear controlled sources and semiconductors (.OP) can also be performed. Time Domain (transient) The Time Domain (transient) analysis is probably the most popular analysis. In this mode, you can plot the various outputs as a function of time. The starting and ending times for the various plots can be input. The accuracy (smoothness) of the output plots can also be controlled by regulating the maximum (time) step size.

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