State True or False against the given statements:

The charge of an electron is 1·6 x 10^-19 J.

Depletion layer is formed by positive charges.

Common base configuration has very high output impedance.

Fixed bias circuit is free from temperature effect.

The maximum efficiency of full wave rectification is 81·2%.

In B.J.T., maximum doping is done in collector.

U.J.T. does not have the ability to amplify.

Select the correct answer from the given four alternatives.

A semiconductor has a

constant temperature coefficient of resistance

negative temperature coefficient of resistance

positive temperature coefficient of resistance

None of these

A zener diode has

negative resistance

very high amplification

sharp breakdown voltage at reverse voltage

None of these

Peak inverse voltage of a full wave centre tap rectifier is

Vm

Vm/sqrt(2)

Vm/n

2Vm

Out of two different Q-points shown in a d.c. load line, the upper Q-point represents the

cut-off point

maximum voltage gain

minimum current gain

maximum current gain

The SCRcan be triggered by a pulse at the

Anode

Gate

Cathode

All of these

In CE configuration, an emitter resistor is used for

higher gain

a.c. signal bypass

stabilization

None of these

Synchronous speed of a 3-phase motor can be given by

Ns 120f/p

NS 120 p/f

Ns f/p x 120

None of these

Discuss the energy band theory with the energy band diagrams of a conductor, a semiconductor and an insulator.

What is doping? How are p-type and n-type semiconductors formed?

A bridge rectifier is connected to 230 V AC, 50 Hz source voltage and load resistance of 20 kn. Calculate:

Output d.c. voltage

Output d.c. current

Ripple voltage

Discuss the working principle of BJT. Derive an expression for transistor current gains.

Explain the working of SCR with its I characteristics.

What is UJT? Discuss its characteristics.

5. Draw logic circuit of half adder and full adder. Explain its working with Truth Table.

With the help of a block diagram, explain the monochrome T.V. transmitter circuit.

What is Transducer Explain the working of LVDT.

Explain the concept of thermocouple type pressure gauge.

Classify the various types of d.c. motors and explain the working of a d.c. series motor.

8. Write short notes on any two of the following:

Single Phase Induction Motor

Storage CRO

X-Y Recorder

DC Tachogenerator