### SOLID STATE DEVICES Multiple Choice Questions Part 5.

1 Who invented the feedback amplifier in 1928?
Henry Brattain
Mark Twain
Harold Black
Bell Labs

2 The arrow in semiconductor symbol
Always points towards the P region and away from the N region
Always points towards the N region and away from the P region
Is not a significant symbol
Always points toward the PN junction

3 If the input power of a half wave rectifier has a frequency of 400 Hertz, then the ripple frequency will be equal to .
800 Hertz
200 Hertz
100 Hertz
400 Hertz

4 If the input frequency of a full-wave rectifier is 400 Hertz, the ripple frequency will be
Twice as great as the input frequency
Equal to the input frequency divided by two
Equal to a quarter of its input frequency

5 What is also called as the conventional amplifier?
Common-collector circuit
Emitter follower circuit
Common base circuit
Common emitter circuit

6 Which of the following is true about the emitter follower circuits?
The output signal is 180º out of phase with the input signal
The output signal is in phase with the input signal
The input signal is always equal to the output signal
An emitter follower circuit is equivalent to a common emitter connection

7 The equation for JFET’s transconductance.
gm = bIc/bVGS
gm = IG/VG
gm = VGS/Ic
gm = Ic/VDS

8 another name for a light activated diode (LAD) is
IR emitter
LED
Photodiode
LCD

9 The semiconductor device that radiate light or utilize light are called
Active devices
Photoelectric devices
Optoelectronic devices
Passive devices

10 Structural category of a semiconductor diodes can be either
Electrolytic and point contact
Junction and point contact
Electrolytic and vacuum
Vacuum and gaseous

11 Zener diodes can be primarily classified as
Forward and reverse biased
Varactor and rectifying
Voltage regulation and voltage reference
Gaseous and hot-carrier

12 The principal characteristics of a tunnel diode.
A constant current under conditions of varying voltage
A negative resistance region
A very high PIV device
An internal capacitance that varies with the applied voltage

13 A special type of semiconductor diode which varies its internal capacitance as the voltage applied to its terminal varies.
Varactor diode
Point contact diode
Zener diode
Silicon controlled rectifier

14 The maximum forward current in a junction diode is limited by its
Peak inverse voltage
Maximum forward voltage
Leakage current
Junction temperature

15 What are the three terminals of a FET?
Gate, source and drain
Plate, cathode and grid
Gate source and battery
Input, output and ground

16 When a transistor is fully saturated,
The emitter current is at its minimum value
The transistor alpha is at its maximum value
The beta of the transistor is at minimal value
The collector current is at its maximum value

17 A FET without a channel and no current occurs with zero gate voltage is
Enhancement-mode FET
Depletion-mode FET
CMOS
Metal-oxide transistor

18 Which of the items below is a special precaution necessary in handling FET and
CMOS devices?
They have fragile leads that it might break off
The are light sensitive
The are susceptible to damage and static charges
They have microwelded semiconductor junctions that are susceptible to breakage

19 A datasheet gives these JFET values; IDSS = 20 mA and pinch-off voltage is 5
volts. What is the gate-source cut-off voltage?
15 volts
10 volts
-5 volts
5 volts

20 What is the dc resistance of the JFET in the ohmic region if the drain to source current at gate shorted is equal to 20 mA and the pinch off voltage is 5 \ volts?
300 fi
250 fi
1 kfi
100 fi

21 Suppose a JFET has IDSS = 7 mA and VGS(off) = -3 V. calculate the drain current for a gate-source voltage of -1V.
3.1 mA
⦁      0.455 A
4.45 mA
31.2 mA

22 What are often called square law devices?
Transistors
Diodes
SCRs
JFETs

23 Equivalent of transistor at saturation in JFETs is ?
Breakdown
Constant-current
Pinch-off
Ohmic

24 When a JFET is cut-off, the depletion layers are
Touching
Separated
Very far apart
Close together

25 The voltage that turns on an enhancement-mode device is the
Gate-source cut-off voltage
Pinch off voltage
Threshold voltage
Knee voltage

26 Depletion–mode MOSFET acts mostly as
A JFET
A voltage source
A resistor
Enhancement-mode MOSFET

27 JFET’s input impedance is
Approaches unity
Approaches zero
Approaches infinity
Is unpredictable

28 The current gain of an emitter follower circuit is
High
Low
Moderate
Very low

29 The drift transistor has a high frequency cut off
Due to the resistance of the base area
Since high collector voltage can be used
Due to its low inherent internal capacitance and low electron transmit time through the base
Due to the large area

30 The maximum operating frequency of a transistor should be percent of the frequency cut-off of the transistor to ensure best performance.
⦁      100
20
80
50

31 When transistor applications call for a temperature operating condition which exceeds 185ºF, which element is most suitable?
Gallium
Antimony
Silicon
Impossible to operate transistor above 185ºF

32 What is the most important factor of a power transistor?
Output resistance
Heat dissipation
Input voltage
Output parameter

33 When the electron transmit time through the base region is very short, this
Creates a higher potential barrier
Makes the transistor unable to amplify its signal
Provides higher cut-off frequency
Provides a zener effect

34 When the transistors are used in video amplifiers, its main limitation is
Low peak voltage
Poor frequency response
Low peak current
Poor filtering of signals

35 Impedance matching in circuit is important for transfer of energy.
Minimum
Enough
Maximum
Limited

36 An amplifier has an output power of 3 watts. Determine the power output level
with reference to 1 mW.
34.77 dBm
40 dBm
-30 dBm
-40 dBm

37 A unijunction transistor is a three terminal consisting of semiconductor layers.
One
Two
Three
Four

38 It is the process by which atoms are constantly losing and regaining free electrons.
Ionization
Covalent bond
Recombination
Parasitism

39 Termed as unwanted oscillation that may occur in most any type of circuits,
oscillator, amplifier, power supply, receiver and transmitters
White noise
Parasitic oscillations
Ripple
Pulsating dc signal

40 Which of the items below describes an RF amplifier which will amplify a weak signal voltage in relatively the same proportion as it will amplify a stronger signal voltage?
Class A amplifier
Linear amplifier
Non-linear amplifier
Inverting amplifier

41 Its maximum amount of reverse voltage which can be applied on a diode before breakdown point is reached.
Zener voltage
Peak inverse voltage
Breakdown voltage
Threshold voltage

42 It refers to any of the over 100 different substances which have never been separated into simpler substances by chemical means and which alone or in combination constitute all matter.
Elements
Atom
Holes
Electrons

43 It is also known as a solid state lamp which utilizes the fall of an electron from the conduction level to the valence level to develop an energy release in the form of heat or light.
LCD
LED
Photodiode
Photoconductive cell

44 Which of the items below is not true with a of a transistor?
It is the current gain of a common-base configuration
It is the ratio of the change in collector current to the change in emitter current
It is usually having a value of unity in some approximations
It is the ratio of the change in collector current to the change in base current.

45 Present atomic theories place the mass and positive charge of an atom in a central nucleus composed of protons and
Holes
Core
Neutrons
Magnetron

46 The as fundamental particle is considered as a bundle of radiant energy or light, the amount energy being related to the frequency.
Protons
LED
Photons
Comet

47 Electron emitted by the mechanical impact of an ion striking a surface is called
Primary electrons
Secondary electrons
Moderately doped electrons
Polarized charge

48 The break up of nuclei into nuclear fragments that are themselves nuclei is called
Fission
Isotope
Neutrino
Atom

49 What particles are of zero charge and zero mass?
Fusion
Neutrino
Fission
Isotopes

50 What is approximate mass of an electron at rest?
⦁       9.1096 x 10^-31 kg
⦁      1.6726 x 10^-27 kg
⦁     1.6762 x 10^-31 kg
⦁     1.7588 x 10^11 kg