Demonstrating the diode equation using a SPICE B behavioural current source.
This is the equation that relates current through a diode to the voltage across it:
Id = Is(exp(qV/(nkT))-1)
Id is the diode current, Is is the reverse bias saturation current, q is the magnitude of charge on an electron. V is the voltage across the diode, k is the Boltzmann constant, T is the absolute temperature of the diode junction (in degrees Kelvin) n is the ideality factor, also known as the quality factor or sometimes emission coefficient. The ideality factor n varies from 1 to 2 depending on the fabrication process and semiconductor material and is often assumed to be approximately equal to 1 (hence the notation n is omitted).
The plot shows the current through the diode vs. the voltage across it.
Imported from LTspiceIV.