switch. Explain. . Describe the function of a transistor as an amplifier with the neat circuit diagram.
Sketch the input and output wave forms. . Give circuit symbol, logical operation, truth table, and Boolean expression of i) AND gate ii) OR gate iii) NOT gate iv) NAND gate v) NOR gate and vi) EX-OR gate. .
State and prove De Morgan’s first and second theorem. . Explain the ampitude modulation with necessary diagrams. .
Explain the basic elements of communication system with the necessary block diagram. . Explain the ground wave propagation and space wave propagation of electromagnetic waves through space. .
List out the advantages and limitations of frequency modulation. . What is meant by satellite communi cation? Give its applications.
IV. Numerical Problems . The given circuit has two ideal diodes connected as shown in figure below. Calculate the current flowing through the resistance R . [Ans: .
A] . Why are NOR and NAND gates called universal gates? . Define barrier potential.
. What is rectification? . List the applications of light emitting diode.
. Give the principle of solar cells. . What is an integrated circuit?
. What is modulation? . Define bandwidth of transmission system.
. What do you mean by skip distance? . Give applications of RADAR.
. What is mobile communication? . Explain centre frequency or resting frequency in frequency modulation.
. What does RADAR stand for? . Fiber optic communication is gaining popularity among the various transmission media -justify.
III. Long Answer Questions . Elucidate the formation of n-type extrinsic semiconductors. .
Explain the formation of depletion region and barrier potential in PN junction diode. . Draw the circuit diagram of a half wave rectifier and explain its working. .
Explain the construction and working of a full wave rectifier. . What is an LED? Give the principle of its operation with a diagram.
. Write a note on photodiode. - - - - - - - - Unit electronics and Communication . In the circuit shown in the figure, the BJT has a current gain (β)