Industrial Electronics Maintenance

Semiconductors in which intentionally impurities are added for making it conductive.

A UJT is operated with gate junction forward- biased while the JFET is normally operated with the emitter junction reverse-biased.

• True
• False

Frequency of oscillation of the device is equal to the reciprocal of the total period in _____________.

• the whole duration of operation
• one cycle
• one positive half cycle
• one negative half cycle

The datasheet of a certain UJT with a silicon diode gives an intrinsic standoff ratio of 0.5, determine the peak point emitter voltage if the supply is 15V.

• 6.8Volts

A diode conducts current under normal conditions when it is _________

• Reverse biased
• Forward biased
• Avalanched
• Saturated

Which of the following is not true about semiconductors?

• resistance increases as their temperature decreases
• possesses qualities that of a conductor and insulator
• conductance increases as their temperature increases
• have less than four valence electrons

What is the resistor value of an ideal diode in the region of conduction?

• 0 ohms
• 1K ohms
• 5K ohms
• Infinity

Majority Carrier in a P-type Semiconductor.

• Acceptor Ion
• Donor Ion
• Positive Charge
• Negative Charge

These are materials that have no current carrying capacity.

• Semiconductor
• Conductors
• Insulators
• Diodes

It is the maximum amount of voltage the diode can withstand in reverse bias mode on a continual basis.

• maximum repetitive reverse voltage
• maximum forward voltage
• maximum dc reverse voltage
• maximum total dissipation

The device which controls the flow of electrons is called _______ device. These devices are the main building blocks of electronic circuits.

• electronic

The silicon bilateral switch has the ability to provide positive and negative cycles.

• True
• False

Defined as a type of extrinsic semiconductor doped with a trivalent impurity element which has three electrons in its valence shell.

• P-type Semiconductor
• N-type Semiconductor
• Intrinsic Semiconductor
• Extrinsic Semiconductor

The motion of electrons through a _______ gives us electric current.

• conductor

Mobile phone chargers are used to charge phone batteries by plugging it to AC power outlets. What type of semiconductor application is employed in the process?

• image projection
• amplification
• rectification
• oscillation

A zener diode has ______ pn junction/s.

• One
• Two
• Three
• None

Outputs from the CMC are provided in the form of?

Describe the different advantages of electronics.

Electronics is the branch of physics and technology concerned with the design of circuits using _____and microchips, and with the behavior and movement of electrons in a semiconductor, conductor, vacuum, or gas.

• transistors

The number 1000 would appear just immediately after

• FFFF (hex)
• 1111 (binary)
• 7777 (octal)
• All of the above

A low power, low current device.

• Silicon Controlled Rectifier
• Silicon Controlled Switch
• Silicon Unilateral Switch
• All of the above

What is the ambient room temperature for electronic devices?

• 280 K
• 290 K
• 300 K
• 310 K

The ripple factor of a half wave rectifier is ______

• 1.414
• 1.21
• .707
• .303

Avalanche breakdown is a condition in which a diode __________.

• is subjected to a large reverse voltage
• is reverse-biased and there is a small leakage current
• has no current flowing at all
• is heated up by large amounts of current in the forward direction

Which of the following does not belong to the group.

• Zero Bias
• Forward Bias
• Reverse Bias
• Neutral Bias

Determine the supply voltage for a silicon PUT if it is determined that η = 0.5, Peak Voltage= 12.3 V. (use the correct unit)

• 23.2V

Which of the following electronic components was invented by Shockley, Bardeen and Brattain?

• transistor
• resistor
• capacitor
• vacuum tubes

Determine RB1 (in ohms) for a silicon PUT if it is determined that η = 0.5, Peak Voltage= 12.3 V and RB2= 1k ohms. (type in the value of the correct answer ONLY)

• 1k

Defined as a type of extrinsic semiconductor doped with a pentavalent impurity element which has five electrons in its valence shell.

• P-type Semiconductor
• N-type Semiconductor
• Intrinsic Semiconductor
• Extrinsic Semiconductor

Which of the following is not a three terminal device?

• Silicon Unilateral Switch
• Silicon Bilateral Switch
• Shockley Diode
• Unijunction Transistor

For an ideal UJT, the emitter firing potential is equivalent to the intrinsic stand-off ratio multiplied by the supply voltage.

• True
• False

These are materials that have excellent current carrying capacity or allow good flow of current through them.

• Capacitors
• Conductors
• Insulators
• Semiconductors

What happens when a p-n junction is forward biased?

• a depletion region is formed
• ions start to build up at the p-n junction
• current starts to flow
• electrons and holes disperse away from each other

Positive logic in a logic circuit is one in which

• Logic 0 and 1 are represented by 0 and positive voltage respectively
• Logic 0 and, -1 are represented by negative and positive voltages respectively
• Logic 0 voltage level is higher than logic 1 voltage level
• logic 0 voltage level is lower than logic 1 voltage level

An OR gate has 6 inputs. The number of input words in its truth table are

• 6
• 32
• 64
• 128

In a semiconductor, the conduction of current is due to _______

• Only Holes
• Only Free Electrons
• Holes and Free Electrons
• None of the above

In a forward bias condition, when the applied voltage is more than the potential barrier of this PN junction the resistance that is offered by the depletion region negligible.

• True
• False

In the energy band phenomenon, at absolute zero temperature, the valence band is ____________.

• Completely filled
• Completely empty
• Halfway filled
• Halfway empty

What type of impurities produce n-type semiconductor?

• acceptor atoms
• trivalent impurities
• extrinsic semiconductor
• donor atoms

What do you call for the gaps left behind by electrons as they are liberated from their respected orbits?

• anion
• holes
• depletion layer
• cation

A semiconductor doped with a pentavalent impurity element which has five electrons in its valence shell.

A career in electronics where he maintains controllers, assembly equipment, copying machines, robots, and other automated or computerized devices.

• computer engineer
• automotive mechanic
• automation mechanic
• computer technician

In a reverse bias condition, the depletion region offers more resistance to these majority carriers.

• True
• False

In the energy band phenomenon, at absolute zero temperature, the conduction band is ____________.

• Completely filled
• Completely empty
• Halfway filled
• Halfway empty

The current in a reverse biased PN junction ______

• increases
• decreases
• equal to 0
• none of the above

These are materials that are bad conductors of current and not allow the flow of current through them as they do not have current carrying capacity.

• Capacitors
• Conductors
• Insulators
• Semiconductors

The application of external voltage across the two terminals.

• Bias

The number of Boolean functions that can be generated by n variables is equal to

• 2n
• 22 n
• 2n-1
• — 2n

Subject code for Aircraft Maintenance Computer System?

• AMT11A-09
• AMT11A-04
• AMT04A-11
• AMT09A-11

In a forward bias condition, further increase in the external applied voltage will increase the size of the depletion region.

• True
• False

Indicate which of the following three binary additions are correct?1.1011 + 1010 = 10101II. 1010 + 1101 = 10111III. 1010 + 1101 = 11111

• I and II
• II and III
• III only

Among the logic families, the family which can be used at very high frequency greater than 100 MHz in a 4 bitsynchronous counter is

• TTLAS
• CMOS
• ECL
• TTLLS

DC power output of half wave rectifier is equal to ____________

• 2(Im)2π2frac{2left(I_mright)^2}{pi^2}π22(Im​)2​
• (Im)22π2RLfrac{left(I_mright)^2}{2pi^2}R_L2π2(Im​)2​RL​
• (Im)2π2RLfrac{left(I_mright)^2}{pi^2}R_Lπ2(Im​)2​RL​
• 4(Im)2π2RLfrac{4left(I_mright)^2}{pi^2}R_Lπ24(Im​)2​RL​

In a silicon bilateral switch, gate terminal can be used to turn off the device.

• True
• False

NAND. gates are preferred over others because these

• Have lower fabrication area
• Can be used to make any gate
• Consume least electronic power
• Provide maximum density in a chip

CMC stands for?

• Central Maintenance Computer
• Central Maintenance Center
• Center Maintenance Computer

If the arrow of crystal diode symbol is positive with respect to the bar, the the diode is in what condition?

• No Bias
• Forward Bias
• Reverse Bias
• None of the above

For a UJT, RB1 may vary from 5kΩ down to 50Ω for a corresponding change of IE from 50 mA to 0 mA.

• True
• False

UJT has a unique characteristics that when it is triggered, the emitter current increases regeneratively until it is limited by emitter power supply.

• True
• False

The structure of UJT is very much similar to an N-channel JFET.

• True
• False

Most of the digital computers do not have floating point hardware because

• floating point hardware is costly
• it is slower than software
• It is not possible to perform floating point addition by hardware
• Of no specific reason

A hexadecimal odometer displays F 52 F. The next reading will be

• F52E
• G52F
• F53F
• F53O

OMS stands for?

• Onboard Maintenance System

System that provide links to the applicable electronic maintenance documentation.

• CMS
• DLCS
• ACMS

What is formed when a dielectric is placed between two parallel conductors?

• capacitance
• resistance
• conductance
• electromotive force

Digital computers are more widely used as compared to analog computers, because they are

• Less expensive
• Always more accurate and faster
• Useful over wider ranges of problem types
• Easier to maintain

These are semiconductors in which intentionally impurities are added to make the element conductive.

Which of the following elements doesn't belong to the group?

• As
• P
• Sb
• Al

Potential barrier of a Silicon.

• 0.1 V
• 0.3 V
• 0.7 V
• .10 V

If a diode is forward biased,

• its state is automatically on
• its state is automatically off
• its state depends on the bias voltage
• its state depends on its diode type

Determine the dc load voltage in the given circuit. Assume the circuit to be ideal.

• 10.8V

A silicon diode displays a forward voltage of .25V at 10mA current at 300 Kelvin. Find the reverse saturation current. (in micro Ampere) *no need to include the unit. 3 decimal places only.

• 0.637

Choose 1 subsystem of Onboard Maintenance System

-The word electronics is derived from ______ mechanics, which means to study the behavior of an electron under different conditions of applied electric field.

• electron

Determine Vo1 and Vo2 in the given circuit.

• 0V

Given the circuit above, determine the value of Vo. Assume that GaAs has a potential barrier of 1.2V.

• 9.3V

Storage of 1 KB means the following number of bytes

• 1000
• 964
• 1024
• 1064

Pick out the CORRECT statement:

• In a positional number system, each symbol represents the same value irrespective of its position
• The highest symbol in a position number system as a value equal to the number of symbols in the system
• It is not always possible to find the exact binary
• Each hexadecimal digit can be represented as a sequence of three binary symbols.

The binary code of (21.125)10 is

• 10101.001
• 10100.001
• 10101.010
• 10100.111

Who among in 1959 from Texas Instruments developed the first integrated circuits?

• J.A. Fleming
• Jack Kilby
• Lee De Forest
• Shockly

What is the lightest subatomic particle?

• neutron
• nucleus
• proton
• electron

Why do we add impurities on semiconductor materials?

• to make the manufacturing easier
• to strengthen its structure
• to improve its electrical properties
• to cut the costs of production

It is the process by which an impurity is added to a semiconductor.

• Mixing
• Doping
• Adding
• Filling

The most commonly used semiconductor is _______

• GaAs
• Si
• Ge
• K

Which is the determining factor for triggering of SUS and SBS?

• Anode gate
• Cathode Gate
• Silicon Diode
• Zener Diode

Diode that is always connected in reverse bias condition.

• Zener

What type of electron emission is employed on vacuum tubes?

• field emission
• thermionic emission
• secondary emission
• photoelectric emission

A NAND gate is called a universal logic element because

• it is used by everybody
• Any logic function can be realized by NAND gates alone
• All the minization techniques are applicable for optimum NAND gate realization
• Many digital computers use NAND gates

Common rating of Silicon Unilateral Switch and Silicon Bilateral Switch

• 0.3 V
• 0.7 V
• 5 V
• 8 V

These type of semiconductors are in their purest form by nature of their existence.

• Intrinsic Semiconductors
• Extrinsic Semiconductors
• P-type Semiconductors
• N-type Semiconductors

One application of UJT is it can amplify signal similar to conventional BJTs and FETs.

• True
• False

BITE stands for?

• Built In Test Equipment
• Built In Text Equipment
• Build In Text Equipment

Give at least 5 various branches in electronics.

Equivalent Circuit of a Unijunction Transistor

• Diode, one fixed resistor, one variable transistor
• Diode, Two resistors (one fixed, one variable)
• Base, Emitter, Collector
• Anode, Cathode, Gate

Determine the current in the given circuit.

• 3.96mA

Which of the following does not belong to the group?

• Zero Biased
• Reverse Biased
• Forward Biased
• Avalanche Biased

In which of the following base systems is 123 not a valid number?

• Base 10
• Base 16
• Base8
• Base 3

It is the main processing unit for an on board maintenance system.

• CMC
• OMS
• BITE

(10101)2 is

• (37)10
• ( 69)10
• (41 )10
• — (5)10

An AND gate will function as OR if

• All the inputs to the gates are “1”
• All the inputs are ‘0’
• Either of the inputs is “1”
• All the inputs and outputs are complemented

Addition of pentavalent impurity to a semiconductor creates _____.

• Free Electrons
• Holes
• Valence Electrons
• Valence Ion

In PUT, the term programmable is applied because RBB, η, and VP as defined for the UJT can be controlled through the internal resistors RB1, RB2, and the supply voltage VBB.

• True
• False

The main advantage of UJT is that it offers negative resistance characteristics.

• True
• False

A reverse-biased silicon diode has about 0.7 V across it

• True
• False

Determine the current (I) in the given circuit.

• 0 ma

Why Si diodes are more preferred in the manufacture of semiconductor devices?

• it is more abundant
• it has lower peak inverse voltage
• it has higher electron mobility
• all of the above

One application of a half wave rectifier is __________

• it converts the DC signal to AC signal
• it converts AC signal to pulsating DC signal
• used as a switch
• it amplifies

In the energy band phenomenon, with the increase in temperature, the resistivity of the material _______ and the conductivity ___________.

• Increases, Increases
• Decreases, Increases
• Increases, Decreases
• Decreases, Decreases

You have an unknown type of diode in a circuit. You measure the voltage across it and find it to be 0.3 V. The diode might be?

• A silicon diode
• A germanium diode
• A forward biased silicon diode
• A forward biased germanium diode

According to Shockley's equation, how can we determine the thermal voltage?

• the product of Boltzmann's constant and absolute temperature divided by the magnitude of electronic charge
• the sum of Boltzmann's constant and absolute temperature divided by the magnitude of electronic charge
• the sum of Boltzmann's constant and absolute temperature multiplied by the magnitude of electronic charge
• the difference of Boltzmann's constant and absolute temperature divided by the magnitude of electronic charge

Being a learner in Electronics 10, which of the seven career in Electronics you will choose? Explain in 3 to 5 sentence paragraph.

It is installed in many systems throughout the aircraft including navigation systems, flight control systems, environmental control systems, and others.

• BITE
• CMC
• OMS

When a PN junction is connected to any external bias, it is considered in thermal equilibrium condition.

• True
• False

What is the octal equivalent of the binary number:10111101

• 675
• 275
• 572
• 573

Which of the following offers good temperature stability?

• SCR
• SUS
• SBS
• All of the above

NSS stands for?

• Network Server System

An electronic system used to facilitate the maintenance of modern aircraft.

• OMS
• CMS
• BITE

The fan put of a 7400 NAND gate is

• 2TTL
• 5TTL
• 8TTL
• 10TTL

The purpose of adding impurity in the semiconductor crystal is to increase the number of free electrons or holes to make it __________

• Conducive
• Stronger
• Increasing
• Conductive

UJT in terms of junction's location is not symmetrical.

• True
• False

The main function of this additional electrode is to prevent electrons from bouncing back to the plate and to lessen the occurrence of secondary emission.

• control grid
• suppressor grid
• screen grid
• anode

Assuming 8 bits for data, 1 bit for parity, I start bit and 2 stop bits, the number of characters that 1200 BPS communication line can transmit is

• 10 CPS
• 120 CPS
• 12CPS
• None of the above

Which in the career in electronics where he/she is responsible to installs, maintains, and repairs computer equipment and systems?

• automotive mechanic
• computer engineer
• automation mechanic
• computer technician

Calculate the power dissipation of a diode having ID = 40 mA.

• 0.028 W

Excess-3 code is known as

• Weighted code
• Cyclic redundancy code
• Self-complementing code
• Algebraic code

The information from BITE are sent to the?

• CMC
• OMS
• DLCS
• ACMS

The width of the depletion layer in a PN junction in forward bias condition _______________

• Decreases
• Increases
• Remains the same
• No depletion region

Diode vacuum tube was the first electronic component invented by _________

• J.A. Fleming

Which of the following is required in determining the charging period of a unijunction transistor?

• Resistor connected to supply, Capacitor, Supply Voltage, Valley and Peak Voltage Values
• Resistors connected to supply and emitter, Capacitor, Supply Voltage, Valley and Peak Voltage Values
• Internal Resistance, Resistor connected to emitter, Valley Voltage and Peak Voltage Values
• Supply Voltage and Intrinsic Stand-off Ratio

Interbase resistance of a UJT is the resistance between emitter and pn junction when the emitter current is zero.

• True
• False

In case of OR gate, no matter what the number of inputs, a

• 1 at any input causes the output to be at logic 1
• 1 at any input causes the output to be at logic 0
• 0 any input causes the output to be at logic 0
• 0 at any input causes the output to be at logic 1

Determine the peak load voltage of the circuit. Assume that the circuit is not ideal.

• 33.3 V

Consider the representation of six-bit numbers by two’s complement, one’s complement, or by sign and magnitude: In which representation is there overflow from the addition of the integers 011000 and 011000?

• Two’s complement only
• Sign and magnitude and one’s complement only
• Two’s complement and one’s complement only
• All three representations

How old am I? (type number only)

• 30

The state of an ideal diode in the region of non conduction is ________

• An open circuit
• A short circuit
• Unpredictable
• Undefined

These are materials that have excellent current carrying capacity.

• Semiconductor
• Conductors
• Insulators
• Diodes

These are materials that have a conductivity between a good conductor and an insulator.

• Semiconductor
• Conductors
• Insulators
• Diodes

What is formed when an n-type and a p-type semiconductor are fused together?

• p-n junction
• ion barrier
• covalent bond
• electron flow

According to this law, the sum of voltages on a closed loop is equal to zero.

• Ohm's Law
• Kirchhoff's Current Law
• Kirchhoff's Voltage Law
• Maxwell's Mesh Current Analysis

DC average current of a half wave rectifier output is ___________

• 2Imπfrac{2I_m}{pi}π2Im​​
• Imπfrac{I_m}{pi}πIm​​
• Im2πfrac{I_m}{2pi}2πIm​​
• 1.414 Imπfrac{1.414 I_m}{pi}π1.414 Im​​

In a PUT, the cathode can be biased to a desired voltage with an external voltage divider, so that when the anode voltage exceeds this “programmed” level, the PUT turns on.

• True
• False

Which of the following gate is a two-level logic gate

• OR gate
• NAND gate
• EXCLUSIVE OR gate
• NOT gate.

Positive Temperature Coefficient means

• resistance increase as temperature decreases
• conductance increases as temperature increases
• resistance decreases as temperature increases
• conductance decreases as temperature temperature increases

Once Programmable Unijunction Transistor is in the on state, the removal of gate voltage will turn the device off.

• True
• False

A half-wave rectifier is used to supply 50V d.c. to a resistive load of 800 Ω. The diode has a resistance of 25 Ω. Calculate a.c. voltage required.

• 161.99 V

The forward voltage drop across a germanium diode is _____.

• 0.3 V

A 5:1 transformer is connected to a half wave rectifier circuit with a 50k ohms load. Compute for the DC current if the input peak voltage is 220V.

• 280.11 microAmpere

A debouncing circuit is

• An astable MV
• A bistable MV
• A latch
• A monostable MV.

A career in electronics where he works in one or more areas of power-generating equipment, power-transmitting equipment, electric motors, machinery control, and lighting and wiring installation.

• electrical engineer
• electrician
• computer engineer
• computer technician

When a pure semiconductor is heated, what happens to its resistance?

• Goes down
• Goes up
• Remains the same
• Becomes zero

Examples of Semiconductor.

These are a special class of elements having a conductivity between that of a good conductor and that of an insulator.

• Capacitors
• Conductors
• Insulators
• Semiconductors

The efficiency of a half-wave rectifier is _______

• Low
• High
• Average
• Zero