3.5 COMPUTER-AIDED CIRCUIT SIMULATION 171- AC LIN 1 79.58 79.58
- 79.58 IS THE SOURCE FREQUENCY IN HZ GIVEN BY 500/(2π)
- PRINT AC IM(R) IP(R) VM(2,3) VP(2,3)
- IM(R) AND IP(R) DENOTE RESPECTIVELY MAGNITUDE AND PHASE OF THE
CURRENT THROUGH THE R ELEMENT - VM (2,3) AND VP (2,3) DENOTE RESPECTIVELY MAGNITUDE AND PHASE OF
THE VOLTAGE BETWEEN NODES 2 AND 3 WITH THE POSITIVE REFERENCE AT
NODE 2
- END
After executing the program, the output file contains the following results:
FREQ I(R) IP(R) V(2,3) VP(2,3)
7 .958E+01 7.071E− 01 − 1 .500E+01 1.061E+ 02 7 .500E+ 01
Note that I(R) is the same as IM(R) directed from the first node number, 1 in this case, given for R
to the second node number, 2 in this case; V(2,3) is the same as VM(2,3). Thus the phasor current
is given byI ̄R= 0. 7071 −15°, and the voltage across the inductor is given byV ̄L= 106. 1 75°.
Note that the magnitudes are the peak values.
−+
vs(t) = 100 cos(500t + 30 °)(a)R = 100 ΩL = 0.3 HC = 40 μFi(t)Figure E3.5.2−+
vs(t) = 100 cos(500t + 30 °)(b)R = 100 ΩL = 0.3 HC = 40 μFiR(t)−+
vL(t)1 230Analysis of Frequency Response with PSpice and PROBE
PSpice can readily accomplish the circuit analysis as a function of frequency, and PROBE
can display Bode plots for magnitude and phase of network transfer functions. Besides the
linear (LIN) frequency sweep that we used in steady-state sinusoidal analysis, with a sim-
ilar syntax statement, a logarithmic frequency sweep, with points specifying the number of
points per octave (an octave represents a twofold increase in frequency) or per decade (a
decade represents a tenfold increase in frequency), can be specified. For example, the
statement
- AC DEC 20 10HZ 1MEGHZ