(4) Obtain the characteristics for the SCR and TRIAC devices. Download a model for the unijunction transistor (UJT). This is a three-terminal device with different ...
book
Mobk059
124
March 9, 2007
10:21
PSPICE FOR CIRCUIT THEORY AND ELECTRONIC DEVICES
FIGURE 7.41: The Table part
(4) Obtain the characteristics for the SCR and TRIAC devices. Download a model for the unijunction transistor (UJT). This is a three-terminal device with different characteristics to the conventional bipolar transistor. Construct a UJT circuit symbol, junction schematic, and plot the output characteristics showing the negative resistance region. (5) Investigate the TABLE part in Fig. 7.41. From the Analysis Setup/DC Sweep/Sweep Variable /Voltage Source, Name = vin. The sweep parameters: Start Value: 0, End Value 10V, and Increment 1. (6) Investigate the BJT switching schematic in Fig. 7.42. (7) Investigate the differential amplifier shown in Fig. 7.43. (8) Investigate root locus plotting using DIFF and Laplace parts in Fig. 7.44. Analysis tab to Analysis type: AC Sweep/Noise, AC Sweep Type to Logarithmic, Start Frequency = 0.001, End Frequency = 10, Points/Decade = 10,001. Press F11 to produce the locus plot shown in Fig. 7.45 but change the x-axis to R(v(out)) and the y-axis to IMG(v(out)). Both of these functions are available from Trace/Add Trace in Probe. However, in the latest edition of PSpice, there is now
FIGURE 7.42: BJT switch
book
Mobk059
March 9, 2007
10:21
SEMICONDUCTOR DEVICES AND CHARACTERISTICS
FIGURE 7.43: Differential amplifier NUM = 24*(s-0.5)
IN
Vin 1V
OUT
+-
Out V
0
DENOM = ((s+1)**2)*(s+2)
FIGURE 7.44: A closed-loop control system
FIGURE 7.45: Change y-axis to IMG(v(out)) and x-axis to R(v(out))
