Which electrical bias is required for an LED to emit light?
Forward bias
An LED is a p–n junction diode. When it is forward biased, electrons from the n-side and holes from the p-side are pushed into the junction region.
There they recombine, and in a direct band-gap semiconductor (such as GaAs or GaAsP) the energy released in each recombination is emitted as a photon of light — electroluminescence.
Under reverse bias, the depletion region widens and almost no carriers cross the junction, so there is no recombination and no light. At zero bias or in open circuit, no current flows and the LED stays dark.
Hence, the answer is Forward bias.
Important Questions from Light Emitting Diode (LED)
If the speed of light in air is represented by e and the speed in a medium is u, then the refractive index of the medium can be calculated using the formula_______.
The basic material for fabrication of an LED is
An LED has a rating of 2 V and 10 mA. If it is connected to a 6V battery, the minimum value of series resistance is
An LED driver circuit does NOT have a/an _________.
What value of a series resistor is required to limit the current through an LED to 20 mA with a forward voltage drop of 2.0 V, when connected to a 10-V supply?
