Obtain the characteristics for the SCR and TRIAC ...

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(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))

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