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402 3. Reference Manual
This netlist describes a
common-emitter amplifier.
Set up a system of
symbolic AC equations.
Approximate the system of
circuit equations.
Inspect the list of
unknowns in the matrix
equation.
Solve the equations for
V$5.
Discard rows and columns
which are not needed to
compute V$5.
Inspect the list of
remaining unknowns.
In[3]:= ceamplifier =
Circuit[
Netlist[
{V1, {1, 0}, 1},
{V0, {6, 0}, 0},
{C1, {1, 2}, Symbolic −> C1, Value −> 1.0*^−7},
{R1, {2, 6}, Symbolic −> R1, Value −> 1.0*^5},
{R2, {2, 0}, Symbolic −> R2, Value −> 47000.},
{RC, {6, 3}, Symbolic −> RC, Value −> 2200.},
{RE, {4, 0}, Symbolic −> RE, Value −> 1000.},
{C2, {3, 5}, Symbolic −> C2, Value −> 1.0*^−6},
{RL, {5, 0}, Symbolic −> RL, Value −> 47000.},
{Q1, {2 −> B, 3 −> C, 4 −> E},
Model −> BJT, Selector −> AC,
CBE −> 30.*^−12, CBC −> 5.*^−12, RBE −> 1000.,
RO −> 10000., BETA −> 200.}
]
]
Out[3]= Circuit
In[4]:= eqs = CircuitEquations[ceamplifier,
ElementValues −> Symbolic]
Out[4]= DAEAC, 10 10
In[5]:= sbg = ApproximateMatrixEquation[eqs, V$5,
{s −> 2. Pi I 10^4, MaxError −> 0.1}]
Out[5]= DAEAC, 10 10
In[6]:= GetVariables[sbg]
Out[6]=
V$1, V$2, V$3, V$4, V$5, V$6, V$X$Q1, I$V1, I$V0, IC$CC$Q1
In[7]:= Solve[sbg, V$5]
Out[7]= V$5 RC
RE
In[8]:= cmat = CompressMatrixEquation[sbg, V$5]
Out[8]= DAEAC, 7 7
In[9]:= GetVariables[cmat]
Out[9]= V$1, V$2, V$3, V$4, V$5, V$X$Q1, IC$CC$Q1
Note that matrix compression does not change the solution of the equations.
Solve the compressed
equations for V$5.
In[10]:= Solve[cmat, V$5]
Out[10]= V$5 RC
RE