Series & Parallel Resonance

Ask

A high – Q quartz crystal exhibits series resonance at the frequency ωs and parallel resonance at the frequency ωp. Then

(a)ωs is very close to, but less than ωp

(b)ωs << ωp

(c)ωs is very close to, but greater than ωp

( d.) ωs >> ωp

Answer is ( )

Concept

Type Reasoning here

Rise Time of Amplifier

Ask

From a measurement of the rise time of the output pulse of an amplifier, whose input is a small amplitude square wave, one can estimate the following parameter of the amplifier

a. Gain-bandwidth product

b. Slew rate

c. Upper 3 dB frequency

d.Lower 3 dB frequency

Answer is ( )

Concept

Type Reasoning here

JFET - Upper Cutoff Frequency

Ask

In the JFET circuit shown, assume that R1|| R2 = 1 MΩ and the total stray capacitance at the output to be 20 pF.Determine the upper cutoff frequency of the amplifier.

(a)3.18MHz

(b)2.46MHz

(c)3.45MHz

(d) None of the above

Answer is ( )

Concept

Type Reasoning here

Resistance Value in Forward Biased & Reverse Biased Conditions

Ask

What does a reading of a large or small resistance in forward- and reverse-biased conditions indicate when checking a transistor using an ohmmeter?

(a) Faulty device

(b) Good device

(c) Bad ohmmeter

(d) None of the above

Answer is ( )

Concept

Type Reasoning here

Transistor Region when Fwd-Based C-B & C-E

Ask

In which region are both the collector-base and base-emitter junctions forward-biased?

(a) Active

(b) Cutoff

(c) Saturation

(d) All of the above

Answer is ( )

Concept

Type Reasoning

Active Region of Common - Emitter

Ask

For what kind of amplifications can the active region of the common-emitter configuration be used?

(a) Voltage

(b) Current

(c) Power

(d) All of the above

Answer is ( )

Concept

Type Reasoning here

Multivibrator

Ask

Consider the following two statements :

Statement 1:  Astable Multivibrator can be used for generating square wave.

Statement 2:  Bistable Multivibrator can be used for storing binary information.

a.      Only statement 1 is correct.

b.      Only statement 2 is correct.

c.      Both the statements 1 and 2 are correct.

d.      Both the statements 1 and 2 are incorrect.

Answer is ( )

Concept

Type Reasoning here

Oscillator association

Ask

Match the following:  a)Hartley             1) Low frequency oscillator

b)Wein-bridge     2) High frequency oscillator

      c)Crystal             3) stable frequency oscillator

                                                        4) Relaxation frequency oscillator

                                                     .  5) Negative resistance oscillator

a) (a)-2 ,( b )- 4 , (c)- 3

b) (a)-2 ,( b )- 1 , (c)- 3

c) (a)-1 ,( b )- 4 , (c)- 5

d) none of the above




Answer is ( )

Concept

Type Reasoning here

Darlington Transistor Z- Parameters

Ask

The Two Port Darlington impedance booster of figure uses identical transistors (hie = 1 KΩ, hfe = 100, hre = hoe = 0).

Calculate the Z – 11 & Z-22 parameters of the network. Use relevant approximations.

a)10.3 MΩ , 2 KΩ

b)10.3 MΩ , 1 KΩ

c)20.3 MΩ , 2 KΩ

d) none of the above

Answer is ( )

Concept

Type Reasoning here

Device to Check Working Condition of Transistor

Ask

Which of the following equipment can check the condition of a transistor?

(a) Current tracer

(b) Digital display meter (DDM)

(c) Ohmmeter (VOM)

(d) All of the above

Answer is ( )

Concept

Type Reasoning here

Transistor ON State

Ask

How much is the base-to-emitter voltage of a transistor in the "on" state?

(a) 0 V

(b) 0.7 V

(c) 0.7 mV

(d) Undefined

Answer is ( )

Concept

Type Reasoning here

PIN Diode

Ask

The number of doped regions in PIN diode is
(a) 1
(b) 2
(c) 3
(d) 1 or 2

Answer is ( )

Concept

Type Reasoning here

Ideal OpAmp

Ask

An ideal opamp is an ideal
(a) Voltage controlled current source
(b) Voltage controlled voltage source
(c) Current controlled current source
(d) Current controlled voltage source



Answer is ( )

Concept

Type Reasoning here

Electron Flow in Semiconductor Crystal

Ask

When a voltage is applied to a semiconductor crystal then the free electrons will flow...
(a) towards positive terminal
(b) towards negative terminal
(c) either towards positive terminal or negative terminal
(d) towards positive terminal for 1 μs and towards negative terminal for next 1 μs


Answer is ( )

Concept

Type Reasoning here

Extrinsic Semiconductors

Ask

At very high temperatures the extrinsic semiconductors become intrinsic because
(a) drive in diffusion of dopants and carriers
(b) band to band transition dominants over impurity ionization
(c) impurity ionization dominants over band to band transition
(d) band to band transition is balanced by impurity ionization





Answer is ( )

Concept

Type Reasoning here

Ideal Closed Loop Gain

Ask

For a stable operational amplifier-feedback network, the ideal closed loop gain can be calculated if which of the following conditions is true:
(a)A negligible differential voltage applied at input terminals, produces a significant output voltage
(b)The current required at either of the op-amp terminals is negligible
(c)both (a) and (b) are true
(d) only (a) is true



Answer is ( )

Concept

Type Reasoning here

Impurity for Si n-p-n Transistor

Ask

Impurity commonly used for realizing the base region of a silicon n-p-n transistor is
(a) Gallium
(b) Indium
(c) Boron
(d) Phosphorous


Answer is (  )

Concept

Type Reasoning here

Reverse Biased P-N Junction

Ask

Assertion (A): A p-n junction has high resistance in reverse direction.
Reason (R): When a reverse bias is applied to p-n junction, the width of depletion layer increases.
(a) Both A and R are true and R is correct explanation of A
(b) Both A and R are true but R is not a correct explanation of A
(c) A is true but R is false
(d) A is false but R is true


Answer is ( a)

Concept

Type Reasoning here

P-N-P Transistor

Ask

In p-n-p transistor the current Ie has two components viz. Iep due to injection of holes from p-region to n-region and Ien due to injection of electrons from n-region to p-region. Then
(a) Iep and Ien are almost equal
(b) Iep >> Ien
(c) Ien >> Iep
(d) either (a) or (c)


Answer is ( b)

Concept

Type Reasoning here

n-channel JFET

Ask

In an n channel JFET, the gate is
(a) n type
(b) p type
(c) either n or p
(d) partially n & partially p


Answer is ( b )

Concept

Type Reasoning here