It is a relatively special diode, it is a current-driven device, the main parameter is the operating current. The light-emitting diode has a forward conduction voltage, and the working current and forward conduction voltage are related to the color of the light-emitting diode, The range is different for different colors.
The volt-ampere characteristic curve of the diode
The light-emitting diode is also a diode. It follows the volt-ampere characteristic curve of the diode and also has the parameter of the turn-on voltage.
During operation, there is a forward voltage drop, and if the voltage changes slightly at this time, it will cause a large change in the current. Generally, to avoid this situation, the light-emitting diode is generally driven by a constant current source.
Operating current and conduction voltage of light-emitting diodes
In the LED lighting industry, light-emitting diodes are driven by constant current drivers. Multiple LEDs are connected in series, and the current flowing through each LED is the same, which can ensure that each LED emits uniformly. When driving a few LEDs, You can connect the light-emitting diode and the current-limiting resistor in series to the voltage.
Take ordinary red light-emitting diodes as an example
The range of forward voltage drop is (1.5-2.6)V, and the maximum working current does not exceed 22mA. By choosing different current-limiting resistor, the light-emitting diode can work normally.