2.a) Explain the concept of diode capacitance. Derive expression for transition capacitance? b) Find the value of D.C. resistance and A.C resistance of a Germanium junction diode at 25C with reverse saturation current, I= 25A and at an applied voltage of 0.2V across the diode. OR 3.a) What do you understand by depletion region at p-n junction? What is the effect of forward and reverse biasing of p-n junction on the depletion region? Explain with necessary diagrams. b) Explain Zener and avalanche breakdown mechanisms in detail. 4. Define the following terms and derive the equations with respect to half-wave rectifier: i) Ripple factor ii) Peak inverse voltage iii) Rectification efficiency iv) % Regulation. 5.a) Draw the circuit diagram of full-wave rectifier with inductor filter. Explain its operation with necessary equations. b) A HWR circuit supplies 100mA DC current to a 2502 load. Find the DC output voltage, PIV rating of a diode and the r.m.s. voltage for the transformer supplying the rectifier 6.a) With neat sketches and necessary waveforms, explain the input and output characteristics of a BJT in CB configuration. Also derive expression for output current. b) Derive the relation among a, and y.