resistor.md

R — Resistor

The resistor is the most basic passive component, opposing the flow of current according to Ohm's law.

Syntax

R<name> <node+> <node-> <value> [TC=<tc1>[,<tc2>]] [M=<m>]
R<name> <node+> <node-> <model_name> [L=<length>] [W=<width>]
R<name> <node+> <node-> VALUE={<expression>}

Parameter	Description
node+, node-	Positive and negative terminal nodes
value	Resistance in ohms
TC=tc1[,tc2]	Temperature coefficients (linear, quadratic)
M=m	Multiplier (parallel instances)
model_name	Reference to a .MODEL definition
VALUE={expr}	Behavioral expression

Examples

* Basic resistor
R1 IN OUT 1k

* With engineering notation
R2 A B 4.7MEG

* Temperature-dependent
R3 IN OUT 10k TC=0.001,0.0001

* Model-based with geometry
R4 IN OUT rmod L=10u W=2u

* Behavioral (expression-based)
R5 IN OUT VALUE={1k * (1 + V(CTRL))}

Model Definition

.MODEL rmod R(RSH=100 NARROW=0.1u)

Temperature Dependence

With temperature coefficients:

$$R(T) = R_0 \times [1 + TC_1 \times (T - T_{nom}) + TC_2 \times (T - T_{nom})^2]$$