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Semiconductors > 3rd year final > Flashcards

3rd year final Flashcards

1
Q

The process by which impurities are added to a semiconducting material to change its electric characteristics is called.

A

Doping

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2
Q

When voltage is applied to a diode, the action occuring in the ____ region either blocks current flow or passes current.

A

Depletion

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3
Q

Capacitive filter elements can be used for smoothing the output _____ across the load.

A

voltage

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4
Q

A diode will conduct normal current when the ___ is positive with respect to the_____.

A

Anode, cathode

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5
Q

The ____ converts AC to a pulsating DC voltage.

A

Rectifier

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6
Q

What determines the load polarity of a power supply the that converts AC to DC?

A

diode

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7
Q

P-Type semiconductors have been doped with a_____ of free electrons.

A

Deficiency

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8
Q

When testing a Zener diode with a Vom your readings indicate a low resistance in both directions, you could probably conclude the Zener diode is _____.

A

Shorted

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9
Q

The primary purpose of a Zener diode is to act as a ______.

A

Voltage regulator

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10
Q

List 4 ways that Diodes can be used in signal and power circuits.

A
  1. Detectors of Radio Waces
  2. Logic Functions
  3. Switching
  4. Signal mixers
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11
Q

Regardless of the way an SCR is shut down, the process is called _____.

A

Commutation

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12
Q

An SCR stays off until a point called ____ breakover voltage is reached.

A

Forward

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13
Q

A ____ device has the ability to produce a voltage in the presence of light.

A

Photovoltaic

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14
Q

The first automatic fire alarm detection device was a _____.

A

Fuseable link heat detector

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15
Q

A_____switch is not a supervisory switch.
a.Room temp b.Vane type flow C.Valve tamper
D.Water Level

A

B.Vane type flow

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16
Q

The most appropriate detection for an atrium is a ____.

A

Projected beam smoke detector

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17
Q

A short circuit on a fire alarm initiating device circuit causes a ____ signal.

A

Trouble

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18
Q

The minimum sound pressure level for an audible fire alarm notification appliance at the pillow in a sleeping area is _____ dBA.

A

75

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19
Q

A firestopping material that expands when heated is referred to as ______.

A

Intumescent

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20
Q

What is the maximum distance that visible notification appliances must be located from the end of a corridor?

A

15 ft

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21
Q

There are five primary functions of a fire alarm system. Name Four

A
  1. Early Detection
  2. Occupant notification
  3. Safely control functions
  4. Building systems management
22
Q

Non power-limited fire alarm systems have a maximum operating voltage of ____volts.

A

600

23
Q

Upon detection of a trouble condition, fire alarm system controls must initiate a trouble signal within ____ seconds.

A

200

24
Q

Name 3 types of supervising stations systems

A
  1. Central
  2. Remote
  3. Proprietary
25
Q

List the four emergency control functions that may be controlled by a fire alarm system.

A
  1. Elevator recall
  2. HVAC shutdown
  3. Door unlocking
  4. Stairway pressurization
26
Q

Name the three basic parts of fire protection

A
  1. Detection
  2. Containment
  3. Suppression
27
Q

A ___device has the ability to produce a voltage in the presence of light.

A

Photo voltaic

28
Q

Regardless of the way an SCR is shut down, the process is called_____.

A

Commutation

29
Q

An SCR stays off until a point called ____ breakover voltage is reached.

A

Forward

30
Q

When light strikes a transparent surface, it is divided into 2 beams….

A

reflective and refractive

31
Q

During testing, a forward biased P-N junction will indicate….

A

Low resistance

32
Q

A ____ is a device that receives a small signal and produces a larger signal.

A

Amplifier

33
Q

The principle operation of fiber optic cable

A

Total internal reflection

34
Q

List 5 steps for processes involved in a complete power supply system.

A

a. Convert to AC power
b. Rectify ac to pulsating DC
c. Filter DC
d. regulate output
e. divide output

35
Q

The main difference between LED and LCD is….

A

LEDS emit light, LCDs control light

36
Q

The primary function of an optocopuler is to provide electrical____ between inputs and outputs.

A

Isolation

37
Q

Which type of fiber optic cable offers the highest data transmission speed?

A

Single Mode

38
Q

Name 3 parts of fiber optic cable

A
  1. Core
  2. Cladding
  3. Buffer
39
Q

Name 2 advantages of photo operated devices

A

Quick switch time,

No contact bounce

40
Q

List 3 ways to prevent transistor thermal instability

A
  1. heat sink
  2. Feedback current
  3. Voltage divider
41
Q

4 advantages of fiber optic cable over conventional copper cable

A
  1. Lighter
  2. No interference
  3. Data security
  4. Faster and larger data capacity
42
Q

Why is lower impedance in a transformer a concern?

A

Higher current flows when a short circuit happens

43
Q

A buck boost is typically used to change voltage between ___ and ___ volts.

A

5 and 25

44
Q

Harmonics create problems by causing excess ____ in a transformer.

A

Heat

45
Q

If frequecy is increased in a parallel RC circuit, the current will ____.

A

Increase

46
Q

3 ways to guard a transformer

A

Elevation, barrier, partitions

47
Q

Two functions served by the liquid in a liquid-immersed transformer

A
  1. Keeps it cool (temperature)
  2. Insulated
  3. Dielectric
48
Q

Two limitations of auto transformers

A
  1. Low impedance

2. No isolation between windings

49
Q

List 4 ways to maintain a transformer (things to look for)

A

a. Loose nuts and bolts
b. Coil damage
c. Loose lamination
d. build up of dust

50
Q

List the four ways diodes can be used in power and signal circuits

A

a. Logic functions
b. As a switch
c. Signal mixers
d. Radio wave detectors.

51
Q

5 functions of a fire alarm system

A
  1. Early detection
  2. Occupant notification
  3. Building systems management
  4. Emergency control functions
  5. Notification of the police department.

Semiconductors (3 decks)

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