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2.4 Setting up and Solving Circuit Equations 73
The values of all these options must be strings which can be converted to a single symbol by means
of the command ToExpression. Strings such as "V_" or "@I" cannot be converted to valid symbols
and may therefore not be used for this purpose.
Changing the Instance Name Separator for Reference Designators
Related to the identifier prefix options is the option InstanceNameSeparator (Section 3.14.2). This
option determines the character (or string) which Analog Insydes uses to separate name components
of reference designators generated for instantiated subcircuit elements. With the default setting
InstanceNameSeparator −> "$"
a resistor RB in a subcircuit instance Q1 would be named RB$Q1. Using SetOptions you can change
the separator character to (almost) anything you like, with the same restrictions that apply to the
choice of the prefix options.
2.4.2 Circuit Equations
The Command CircuitEquations
Setting up systems of symbolic circuit equations is done by the Analog Insydes command
CircuitEquations (Section 3.5.1), which takes a Netlist or Circuit object as first argument. In
addition, the function may be called with a variety of options – to be introduced later – with which
many aspects of equation setup can be influenced individually:
CircuitEquations[circuit, options]
If the type of the netlist argument is not a flat netlist, then the function ExpandSubcircuits
(Section 3.4.1) is automatically applied to the circuit description in order to produce a flat netlist
object before proceeding with equation setup.
This section describes how to set up equations of linear circuits in the Laplace domain.
CircuitEquations can also be used to set up DC or transient equations for nonlinear circuits. This
topic is discussed in Section 2.6.4.
1
RA
2
L1
3
V0
C1
C2
RB
Figure 4.1: RLC filter circuit