pspice dependent sources

8/12/2019 PSpice Dependent Sources

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in Cadence/OrCAD PSpice


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Objective of LectureIntroduce the parts in PSpice for dependent voltageand current sources.

Describe how to set the part properties to set thecoefficient a for the dependent source.Explain some issues that arise when connecting theseparts in the schematics layout tool in PSpice.


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Dependent SourcesType of Source Acronym Symbol in

TextPart Namein PSpice

Symbol inPSpice

VoltageControlled

Voltage Source VCVS ECurrent

ControlledCurrent Source

CCCS F

VoltageControlled

Current Source VCCS G

CurrentControlled

Voltage SourceCCVS H

where a is a cofficient and I and V are the current and voltage at some other point in the circuit.


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CCCS Implementation in PSpice


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Part FDouble click on F to set the value of the coefficient(a = 3 in this example) that is multiplied by the

current through R1 to set the current through thedependent current source.


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Layout Issues Wrong: The dependent currentsource will act as a short across R1

Correct: The current that flowsthrough R1 enters the dependentcurrent source.


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Layout IssuesTo implement the circuit exactly in PSpice, the wires toPart F had to criss-cross each other on the input andoutput terminals in order to get the direction of thearrows to follow the direction of the currents in theoriginal circuit.


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Layout IssuesBoth of the wires were extendedout laterally from Part F beforerunning one across the other

wire.

If this was not done, a connectionbetween the terminal on Part F would have been automaticallymade. A node dot would show up onthe circuit schematic), creating a

short between the two wires.

Node created bycriss-crossing

wires


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Layout IssuesTo minimize running wires like this, you can changethe orientation of the part in the circuit.

Keystroke shortcuts in OrCAD PSpiceCnt-R is RotateCnt-F is FlipCnt-M is Mirror


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Layout IssuesOriginal layout

After rotating andflipping Part F.


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Layout Issues Alternatively, you can changed the sign on thecoefficient, F, on Part F to eliminate one of the criss-crossing connections.


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VCVS

The connections for the reference voltage used to set the voltagecontrolled voltage source are made across the component with the sideson the part matching the signs for V R on the circuit.

Implementation in PSpice


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CCVS Implementation in PSpice


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VCCS Implementation in PSpice

Changing the sign on the coefficient of the reference voltage in Part Geliminated the need to criss-cross wires on the current source side of the

VCCS.


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SummaryThe names of the parts in PSpice that are dependentsources have been identified and the way to modifythe coefficient a was demonstrated.

VCVS: Part ECCCS: Part F VCCS: Part G

CCVS: Part HThe control portion of the part is incorporated into thecircuit in the same manner that a voltage or currentmeasurement is made using a digital multimeter.

pspice dependent sources

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