The PSpice schematic for the filtered full-wave diode rectifier. All of the switch default values were used for this simulation.įigure 7.57. The final parameter is “ttran,” which is the time it takes to make the transition from the high-impedance state to the low-impedance state. The “tClose” variable indicates the time when the switch begins to change from its open state to its closed state. In particular, care should be taken if either of these values is the same order of magnitude as other resistances in the circuit. The default values are given in the dialog box and can be changed if necessary. However, for numerical reasons and because some switches are nonideal, the switch model has the parameters Ropen and Rclosed to model the nonideal open and closed resistances of the switch, respectfully. An ideal switch is modeled by infinite open resistance and zero closed resistance. The first property is the Package Reference Designator “PKGREF” (i.e., name) which uniquely identifies each part that is placed in the circuit. There are five properties of this model that can be adjusted.
The properties of the switch can be found by double-clicking on the switch after it has been placed in the circuit. Pressing the “OK” button will select the switch and it can then be placed on the schematic in the usual way. This name will appear in the “Part Name” box at the top of the window and the description “Switch: closes at tClose= ?” will appear directly below the part name box. The switch required for this example can be found by clicking on the “eval.slb” library (using the scroll bars if necessary) and scrolling down the parts list until the name “Sw_tClose” is visible. That button brings up the “Get Part” dialog box that lists the various libraries that contain the part models and lists the parts contained in whichever library is highlighted. If one is uncertain of the name of a circuit model or even uncertain if a model exists, one can press the “Browse…” button in the “Add Part” dialog box for help.
The part name for the switch is “Sw_tClose,” which can be accessed by typing this name in the “Add Part” dialog box.
The PSpice schematic for the circuit in Example 7.5.
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