Electrical resistors are fundamental components in electronic circuits, designed to limit current flow, divide voltages, and dissipate power. They are widely used in automation, industrial control, and MRO applications for precision signal conditioning, motor control, and circuit protection. Common types include fixed resistors (carbon film, metal film, wirewound), variable resistors (potentiometers, rheostats), and specialized variants like thermistors and photoresistors. Key specifications include resistance value (Ohms), tolerance, power rating, and temperature coefficient. Resistors enable stable operation of sensors, PLCs, drives, and other automation equipment by ensuring accurate current regulation and voltage division.