1. Name the semiconductor device that can be used to regulate an unregulated dc power supply. With the help of I-V characteristics of this device, explain its working principle.
2. Distinguish between ‘intrinsic’ and ‘extrinsic’ semiconductors.
3. Explain, with the help of a circuit diagram, the working of a p-n junction diode as a half-wave rectifier.
4. Write any two distinguishing features between conductors, semiconductors and insulators on the basis of energy band diagrams.
5. Write any two distinguishing features between conductors, semiconductors and insulators on the basis of energy band diagrams.
1. Answer the following questions based on above information:
(i) What were the values displayed by Meeta and her father?
(ii) What answer did Meeta’s father give?
(iii) What are the tiny lights in traffic signals called and how do these operate?
2. How is a zener diode fabricated so as to make it a special purpose diode? Draw I-V characteristics of zener diode and explain the significance of breakdown voltage. Explain briefly, with the help of a circuit diagram, how a p-n junction diode works as a half wave rectifier.
3. (a) With the help of circuit diagram explain the working principle of a transistor amplifier as an oscillator.
(b) Distinguish between a conductor, a semiconductor, a semiconductor and an insulator on the basis of energy band diagrams.
4. In a transistor, doping level in base is increased slightly. How will it affect (i) collector current and (ii) base current?
5. Draw the transfer characteristic curve of a transistor in CE configuration. Explain clearly how the active region of the V0 versus Vi– curve in a transistor is used as an amplifier.