Resistor (1/4 W carbon film)Through-hole carbon film resistor · YAGEO CFR-25

A resistor opposes current in a fixed proportion to the voltage across it: V = I × R (Ohm’s law). It turns the electrical energy it takes, P = V × I = I² × R, into heat, so every resistor has a power rating as well as a resistance. Resistors set currents (an LED’s series resistor), divide voltages (a sensor or reference divider), pull signals to a defined level and form timing networks with capacitors. They have no polarity: either end can face the supply. This page uses the YAGEO CFR-25, a 1/4 W carbon film resistor in an axial package with colour bands. It carries full power up to 70 °C ambient, may never see more than √(P × R) or 250 V, and changes by up to −500 to +350 ppm/°C below 100 kΩ.