ECE201 Lect-261 AC PSpice Analysis (7.9) Dr. S. M. Goodnick October 29, 2003

ECE201 Lect-262 PSpice Analysis of AC Circuits We must use AC sources, and tell PSpice to perform an AC analysis at specific frequency(ies) PROBE allows us to plot our results Take advantage of features (e.g., cursors) to assist your analysis Completely annotate your schematic diagrams MOST IMPORTANT RULE: You will always get an answer, you must judge its validity!

ECE201 Lect-263 AC Sources in PSpice VAC is used to represent an AC voltage source in PSpice; IAC is for an AC current source Both the magnitude (ACMAG) and phase (ACPHASE) value can be set for the source The frequency is not set using the source VSIN and ISIN are transient sine sources

ECE201 Lect-264 PSpice AC Frequency Selection The frequency selection is specified in the AC Sweep option of the Analysis Setup PSpice can be used to analyze a circuit at a single frequency (for example, 60 Hz) or for an entire range of frequencies (variable) Single frequency: select a linear sweep with 1 point using same start and end freq. VPRINT may be used to output results

ECE201 Lect-265 PSpice Variable AC Frequency Variable frequencies: typically select a decade sweep with about 20 pts/decade with a start and end frequency, respectively, well below and well above the frequencies of interest [think of it as taking a photograph] These results are graphed using PROBE; and this is made easier using voltage and current markers

ECE201 Lect-266 Class Example Learning Example 7.18