res_var :
A variable resistor circuit element.

The res_var primitive represents a two-terminal resistor of which resistance varies with the voltage across the two terminals, pos and neg.

The parameter R is a real-typed array defining the voltage-dependent resistance as a piecewise-constant (PWC) function using the following coefficients:

'{R0, V1, R1, V2, R2, V3, R3, ..., RN}.

meaning that the resistance R is:

R = R0     for V < V1,
    R1     for V1 <= V < V2,
    R2     for V2 <= V < V3,
    ...
    R(N-1) for V(N-1) <= V < VN,
    RN     for VN <= V.

Note that the array has an odd number of elements since it starts with a resistance value (R0) and ends with a resistance value (RN). The piecewise-constant resistance means that the resistor has a piecewise-linear I-V relationship.

Note that this primitive is a pseudo-module to describe a structural netlist of electrical circuits and not a behavioral model by itself. The XMODEL simulator extracts an event-driven behavioral model at run-time based on the circuit network described by these circuit-level pseudo-modules.

Input/Output Terminals

Name	I/O	Type	Description
pos	input	xreal	positive terminal
neg	input	xreal	negative terminal

Parameters

Name	Type	Default	Unit	Description
R	real array	‘{1.0}	ohms	PWC resistance
Cpos	real	0.0	farads	pos-to-gnd capacitance
Cneg	real	0.0	farads	neg-to-gnd capacitance