Resistor

passive Symbol: R

A passive electronic component that limits current flow

Resistor

A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element.

What it is

Resistors limit the flow of Current in a circuit. They are measured in ohms (Ω) and provide Resistance.

How you use it

Resistors are used to:

Limit Current to LEDs
Create Voltage dividers
Pull up or pull down signals (Pull-up Resistor, Pull-down Resistor)
Set timing in RC circuits (with Capacitors)

Use the Ohm’s Law Calculator to calculate Voltage, Current, or Resistance values.

Types

Carbon film - Common, inexpensive, general purpose
Ceramic Resistor - Higher Power rating, better temperature stability
Metal film - More precise, lower noise

Gotchas

Warning

Power rating matters - don’t exceed the wattage (see Power). Exceeding the power rating can cause the Resistor to overheat and fail.

Tolerance affects precision
Temperature can affect Resistance

This component relates to Voltage, Current, and Resistance. Essential for working with LEDs and other components.