Efficient LED lighting requires choosing the correct current-limiting resistor. LEDs require a direct current to provide a forward voltage and operate most efficiently around 3V, but drawing too much current reduces lifespan. Using multiple LEDs in series requires less power from the resistor than overdriving single LEDs. Resistor selection depends on factors like supply voltage, LED voltage, desired current, and tolerances. Higher power LEDs may require resistors rated for over 10W, and wirewound or film resistors can meet these needs. Understanding LED operation helps specify the right resistor type.