Question

The junction capacitance of a linearly graded pn junction varies with the applied reverse bias as

Answer 1

The I-V model derived earlier is valid under steady state conditions when charges, currents and voltages are static. To determine the behavior of the PN junction under time varying excitation, we start from the continuity equation where time explicitly comes into picture:

 

where A is the area of the device. Integrating this equation across the depletion region gives: