Preferred syntax:
.VCR label n+ n- nc+ nc- expression
Alternate syntax:
Gxxxxxxx n+ n- VCR nc+ nc- expression
Voltage controlled resistor.
N+ and n- are the positive and negative element (output) nodes, respectively. Nc+ and nc- are the positive and negative controlling nodes, respectively. Value is the transfactor in ohms per volt.
The simulator will faithfully give you a negative resistor if it
seems appropriate. Usually, this part is used with a behavioral
modeling function, like PWL, which allows you to specify a table of
resistance vs. voltage.