Properties

Forward current I_F [mA]

The forward current of an LED is the current flowing through the LED in forward direction from the anode (+) to the cathode (-). For the maximum forward current, a distinction can be made between the maximum current in continuous light mode and in pulse mode. The maximum forward current is usually higher in pulse mode than in continuous light mode.

Nominal current I_N [mA]

If the LED is operated with a forward current equal to the nominal current, the LED has the characteristics specified in its data sheet, e.g. the nominal brightness. Operation with I_F greater than I_N reduces the service life of the LED due to increased heat generation. Common nominal currents for LEDs are 20 mA, 350 mA and 1000 mA.

Conducting voltage U_D [V]

The conducting voltage indicates the level of electrical voltage required for the LED to become conductive. When the conducting voltage is applied between the anode (+) and the cathode (-), a current flows through the LED in forward direction. The conducting voltage level of an LED depends on the semiconducting material. Typical values for the conducting voltage of various LEDs are, for example, 1.6 V for red and 2.6 V for blue emitting LEDs (see Colors).

Forward voltage U_F [V]

The forward voltage of an LED is the voltage applied in the forward direction between the anode (+) and the cathode (-). The forward voltage is a function of the forward current U_F = f(I_F). This dependence is strongly non-linear. The relationship between U_F and I_F is shown as an example in the chapter Characteristic curve.

Reverse voltage U_R [V]

The reverse voltage is the electrical voltage applied to the LED in reverse direction. Data sheets usually indicate the maximum reverse voltage. This maximum reverse voltage must not be exceeded, otherwise the LED can be irreversibly damaged. A typical value for the reverse voltage of an LED is 5 V.

Typ. wavelength λ [nm]

The typical wavelength is the wavelength of the emitted light at the nominal current.