ABSTRACT

Such a proportionality relationship does not hold for a semiconductor diode and hence an LED (Figure 13.1). Instead, the voltage and current are exponentially related (Hartberger 2011). us, the forward voltage drop

VF across an LED and the forward current IF owing through it obey the equation

V I k

I IF F( ) ln=

 

 

 

 

0 (13.8)

where k, I0 are constants that set the scales, respectively, for voltage and current, having typical values for commercial white LEDs at room temperature: k = 3.64 V−1 and I0 = 3.2 × 10−6 A.