Article 5
Luminous Intensity of an LED as a Function of Input Power
by Sean King
Abstract
When current passes through a light-emitting diode (LED), the LED emits an incoherent narrow spectrum of light. The relationship between the input power and the light intensity of an LED is studied in this research. Voltage ranging from 2 to 4 Volts was applied to a blue LED. The voltage across the LED, current through the LED and intensity of the light emitted by the LED were measured. For voltages ranging from 2.4 to 3.5 V, light intensity was found to be linearly related to both the current and the voltage. The input power was found to be directly proportional to the square of light intensity. For voltages above 3.5 V, the emission intensity remained constant, independent of the applied voltage.