The controlled generators described by arbitrary functions allow to define the functional or behavioral models of an analog circuit using mathematical equations. The voltage or current waveform is described by:
V=expression or I=expression
The value of V or I determines the voltage across or current through the device. The expression given for V or I may be any function of voltages and currents.
To reference in an expression the voltage at a node in your circuit, you must first name the node in the schematic using a Net Label. You then use the name defined in the Net field of the Net Label's properties to reference the node using the following syntax:
V(Net1) - The voltage at the node Net1 relative to the ground node.
V(Net1,Net2) - The voltage difference between nodes Net1 and Net2.
To reference in an expression the currents through voltage sources, you must first list the sources in the VSRC parameter. You then use the name I1 to refer to the first generator in the list, I2 to refer to the second etc..
You can specify the name of the generator directly in the expression using the following syntax:
I(Vsrc) - The current flowing in the independent voltage source Vsrc.
Parameters
| Parameter | Description |
|---|---|
| Value | Expression defining the source waveform. This value is used only if the EXPR parameter is not specified. |
| EXPR | Expression defining the source waveform. If omitted, it will use the value specified in the value. |
| VSRC | Specifies the list of independent voltage sources through which the control currents flow. The names of the individual generators must be separated by a space character. The component accepts up to a maximum of 5 generators. I1 in the expression must be used to refer to the first control current (first generator specified in the parameter VSRC), I2 to refer to the second current control etc. |
Example
Power expression: V(net1)*I1
Voltage summer expression: V(net1)+V(net2)