Problem 11.6 - Thevenin Equivalent Circuit Using Frequency-Domain Analysis
*
* NOTE: This is a four-part problem.
* 1. Find the Thevenin equivalent of the open-circuited transformer
* circuit. Use PSpice to determine the open-circuit voltage. NOTE:
* For PSpice to calculate the open-circuit voltage, it will be
* necessary to approximate the open circuit by attaching a large
* resistance at the output terminals. (1E9 ohms is a very large R.)
*
* 2. Use a 1-ampere current source at the output terminals to find
* the output (Thevenin equivalent) impedance of the circuit.
* Note that all independent sources must have their output reduced
* to zero (but remain in the circuit) for impedance measurements.
*
* 3. CHALLENGE PROBLEM! If the frequency domain Thevenin equivalent
* impedance is Zth = R+jX, set the load impedance Z = R-jX. This is
* referred to as the complex conjugate of the Thevenin impedance.
* Solve for the R and C values of the load impedance.
* Connect the calculated R and C values at the load terminals 4,0.
* Use PSpice to determine the load voltage and load current.
*
* 4. Construct the Thevenin equivalent circuit in a PSpice program.
* That is, use the Thevenin open-circuit voltage and the Thevenin
* impedance in series, in the usual Thevenin equivalent circuit.
* Attach the complex conjugate RC load from Part 2. Run a program
* to determine the load voltage and the load current.
* The results should agree with Part 2 to four significant figures.
*
.OPT NOPAGE NOBIAS NUMDGT=5
V1 1 0 ; Complete the source specification.
R1 1 2 1
R2 3 4 1
RX 4 0 ??? ; Resistance added to provide a means
; of calculating the open circuit
; (Thevenin) voltage.
L1 2 0 8M
L2 3 0 10M
K1 L1 L2 ????? ; Calculate K to five significant figures.
.AC LIN 1 ??????? ??????? ; Complete the .AC sweep command.
.PRINT AC VM(4) VP(4)
.END
Problem 11.6, Part 2. Thevenin Equivalent Using Frequency-Domain Analysis
*
* Use current source at nodes 4,0 to determine frequency domain
* Thevenin equivalent impedance. All independent sources must
* be reduced to zero for this calculation.
*
.OPT NOPAGE NOBIAS NUMDGT=5
V1 1 0 ; Complete the circuit description file.
I1 0 4
R1 1 2 1
R2 3 4 1
L1 2 0 8M
L2 3 0 10M
K1 L1 L2 ?????
.AC LIN 1 ??????? ???????
.PRINT AC VM(4) VP(4)
.END
Problem 11.6, Part 3. CHALLENGE PROBLEM! Original Circuit with Matched Load
.OPT NOPAGE NOBIAS
V1 1 0 ; Complete the circuit description file.
R1 1 2 1
R2 3 4 1
L1 2 0 8M
L2 3 0 10M
K1 L1 L2 ?????
RL 4 5 ?????
CL 5 0 ?????
.AC LIN 1 ??????? ???????
.PRINT AC VM(4) VP(4) IM(RL) IP(RL)
.END
Problem 11.6, Part 4. CHALLENGE PROBLEM! Thevenin Circuit with Matched Load
.OPT NOPAGE NOBIAS
Vthev 1 0 AC ?????? 7.125 ; Use four or five significant figures
Rthev 1 2 ?????? ; for all values entered in the equivalent
Lthev 2 4 9.5077M ; circuit.
RL 4 5 ??????
CL 5 0 ??????
.AC LIN 1 ??????? ???????
.PRINT AC VM(4) VP(4) IM(RL) IP(RL)
.END