Q.37- Explain the working principle of DC generator and DC motor. Q.38- Draw and explain a typical V-I characteristics of a semiconductor diode. Q.39- Explain the working of NPN transistor and with the help of necessary diagram explain the current components of transistor. Q.40- Draw and explain the V-I characteristics of SCR. Q.41- Draw the circuit diagram of a bridge rectifier and explain its working. Q.42- Draw the circuit diagram of a full wave rectifier and explain its working. Q.43- Write a short note on IGBT.