A P-N junction diode with T = 100 ns conducts a forward-bias current I D = 4.3 mA. At time t = 0, the

A P-N junction diode with τ _T = 100 ns conducts a forward-bias current I _D  = 4.3 mA. At time t = 0, the circuit conditions change, so that a reverse-bias voltage V _E = 20 V is connected in series with the diode and a resistor R = 1KΩ.

(a) Because of the strong discharging current ( 20.7 V/1 k2 = 20.7 mA), the contribution of the recombination to the stored charge removal can be neglected. How long will it take for the stored charge to be removed? (b) If VE = 0, the diode is discharged with a much smaller current (0.7 V/1 k2 = 0.7 mA), so that the contribution from the recombination cannot be neglected. If it is found that it takes trs = 200 ns for the stored charge to be removed, how much stored charge is removed by recombination? A